DEFINITION OF ENGINEERING DESIGN Introduction

The economic future of India depends on our ability to design make and sell competitive products Excellent design and effective manufacture are the pre-requisites of a successive industry There is a general impression that the quality of Indian products can still be improved The fact that consumers have lost their confidence on Indian-made products cannot be denied This problem can be solved only by designing and manufacturing better products through improved methodology Keeping this in view the subject ldquoDesign and manufacturingrdquo purpose to present the methods and procedures of design and manufacture Although engineers are not the only people who design things the professional practice of engineering is largely concerned with design It is usually said that design is the essence of engineering The ability to design is both a science and an art The science can be learned through procedures developed by eminent scholars But the art can be learned only by doing design

Types of Products

A product is the tangible end result of a manufacturing process and is meant for satisfying human needs The product can be classified as follows -

1 Convenience goods

These are less expensive and are clustered around shops and restaurants These can be purchased at consumers convenienceEg Cigarette Candy Magazines etc

2 Shopping goods

These are expensive and people buy it less frequentlyEg Jewellary garments etc

3 Specialty goods

These are purchased taking extra painEg Rare objects like stamps

4 Industrial goods

These are items used in the production of other itemsEg Raw materials

Another way of classifying products is into1 Continuous Products and2 Discrete productsThe continuous products are those which are produced in a continuous

fashion For example plates sheets tubes and bars etc are produced in very long lengths and then these are cut into desired lengths On the other hand discrete products are produced one after another each in separate units On the basis of the output product the Industry is usually named as continuous industry and discrete industry

Requirements in a good product

Customer Satisfaction Profit

How to achieve customer satisfaction

The product should function properly It must have desired accuracy It must have desired reliability It must be easy to operate It must be serviceable It must make minimum space utilization It must withstand rough handling Pleasant appearances Reasonable price

How can it be profitable

It must be easy to manufacture The raw material must be cheap and easily available The manufacturing process has to the decided on the basis of quantity to be

produced It must use standard parts It must be easy to pack and distribute

Definition of Design

Designing is such a vast field that it is defined in several ways Various definitions of designing as pronounced by well-known designers are

ldquoDesign is that which defines solutions to problem which have previously been solved in a different wayrdquo

ldquo Design is the conscious human process of planning physical things that display a new form in response to some pre-determined needrdquo

ldquoDesign is an act of collecting all pertinent information for the production of goods and services to meet some human needrdquo

The design of any component includes two thingso Product design

o Process design

The product design involves the development of specification for a product that will be functionally sound good in appearance and will give satisfactory performance for an adequate life

The process design involves developing methods of manufacture of the products so that the component can be produced at a reasonably low cost

History of Design Process

o Design by Single Person

o Over-the-wall design

o Simultaneous Engineering

o Concurrent Engineering

o Integrated design and Manufacture

In olden times one person could design and manufacture an entire product Even for a large project such as the design of a ship or a bridge one person had sufficient knowledge of the Physics Materials and manufacturing processes to manage all aspects of the design and construction of the project This period is referred to as the period of design by single person in the history of design

By the middle of the 20th century products and manufacturing processes became so complex that one person could not handle all aspects of design and manufacturing This situation led to over-the-wall design process

In this method each functional departments were separated from others as shown by wall There was only one-way communications between Customer Marketing Engg Design and production department The customers lsquothrow their needs to marketing department The marketing department may throw the customer needs to the design department in many instances orally The Engg Design department may conceive a design and hands it over to the manufacturing sections The manufacturing department interprets that design and makes the product according to what they think suitable Unfortunately often what is manufactured by a company using over-the-wall process is not what the customers had in mind This is due to lack of interaction between the different departments Thus this

single direction over-the-wall approach is inefficient and costly and may result in poor quality products

By the early 1980s the concept of simultaneous engineering emerged This philosophy emphasized simultaneous development of the manufacturing process- the goal was the simultaneous development of the product and the manufacturing process This was accomplished by assigning manufacturing representatives to be members of design team so that they could interact with the design engineers throughout the designs processIn the 1980s the simultaneous design philosophy was broadened and called concurrent engineering A short definition of concurrent engineering is the simultaneous progression of all aspects at all stages of product development product specification design process and equipment etc In concurrent engineering the primary focus is on the integration of teams of people having a stake in the product design tools and techniques and information about the product and the processes used to develop and manufacture it Tools and techniques connect the teams with the information Although many of the tools are computer-based much design work is still done with pencil and paper In fact concurrent engineering is 80 company culture and 20 computer support

With the advent of computer technology drastic changes have taken place in the field of design and manufacturing The result was a completely integrated design and manufacturing system This system makes a good use of technologies such as CADCAM FMS etc The computer integrated manufacturing systems (CIMS) moves towards the lsquoFactory of the future CIMS is necessary for better quality efficiency and productivity

TYPES OF DESIGNS

The design can be classified in many ways On the basis of knowledge skill and creativity required in the designing process the designs are broadly classified into three types

Adaptive Design (W 95 97 98 lsquo00) Variant Design (S 97 99) Original Design

Adaptive Design

In most design situations the designers job is to make a slight modification of the existing design These are called adaptive designs This type of design needs no special knowledge or skill Eg converting mechanical watches into a new shape

Variant Design

This type of design demands considerable scientific training and design ability in order to modify the existing designs into a new idea by adopting a new material or a different method of manufacture In this case though the designer starts from the existing designs the final product may be entirely different from the original productEg converting mechanical watches into quartz watches Here a new technology is adopted

Original Design

Here the designer designs something that did not exist previously Thus it is also called new design or innovative design For making original designs a lot of research work knowledge and creativity are essential A company thinks of new design when there is a new technology available or when there is enough market push Since this type of design demands maximum creativity from the part of the designer these are also called creative designs

On the basis of the nature of design problem design may be classified as

o Selection design

o Configuration design

o Parametric design

o Original design

o Re-design

Selection Design

It involves choosing one or more items from a list of similar items We do this by using cataloguesEg -Selection of a bearing from a bearing catalogue-Selection of a fan for cooling equipment-Selecting a shaft Configuration Layout Packaging Design

In this type of problem all the components have been designed and the problem is how to assemble them into the completed product This type of design is similar to arranging furniture in a living room

Consider the packing of electronic components in a laptop computer A laptop computer has a keyboard power supply a main circuit board a hard disk drive a floppy disk drive and room for two extension boards Each component is of known design and has certain constraints on its position For example the extension slots must be adjacent to the main circuit board and the keyboard must be in front of the machine

Keyboard

Main Circuit board

Extension slots

Floppy drive Power supply

The different components are shown above The designers aim is to find how to fit all the components in a case Where do we put what One method for solving such problems is to ndash select a component randomly from the list and position it in the case so that all the constraints on that component are met

Lets take keyboard first It is placed in the front Then we select and place a second component This procedure is continued until we reach a conflict or all the components are in the case If a conflict arises we back up and try again Two potential configurations are shown above Parametric Design

Parametric design involves finding values for the features that characterize the object being studied

Consider a simple example ndashWe want to design a cylindrical storage tank that must hold 4 m 3 of liquidThe volume is given by

V = r 2 lThe tank is described by the parameters radius r and length l Given V = 4 m 3 = r 2 l

r 2 l = 1273We can see a number of values for the radius and length that will satisfy this

equation Each combination-values of r and l gives a possible solution for the design problem

Original Design

As described in an earlier section an original design in the development of an assembly or component that did not exist before

Redesign

The redesign is a modification of an existing product to meet new requirements It is same as adaptive design Most design problems solved in industry are for the redesign of an existing product Suppose a manufacturer of hydraulic cylinders makes a product that is 025m long If the customer needs a cylinder 03m long the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need

On the basis of the objective or strategy the designs are of following main types

o Production Design

o Functional Design

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

These are purchased taking extra painEg Rare objects like stamps

4 Industrial goods

These are items used in the production of other itemsEg Raw materials

Another way of classifying products is into1 Continuous Products and2 Discrete productsThe continuous products are those which are produced in a continuous

fashion For example plates sheets tubes and bars etc are produced in very long lengths and then these are cut into desired lengths On the other hand discrete products are produced one after another each in separate units On the basis of the output product the Industry is usually named as continuous industry and discrete industry

Requirements in a good product

Customer Satisfaction Profit

How to achieve customer satisfaction

The product should function properly It must have desired accuracy It must have desired reliability It must be easy to operate It must be serviceable It must make minimum space utilization It must withstand rough handling Pleasant appearances Reasonable price

How can it be profitable

It must be easy to manufacture The raw material must be cheap and easily available The manufacturing process has to the decided on the basis of quantity to be

produced It must use standard parts It must be easy to pack and distribute

Definition of Design

Designing is such a vast field that it is defined in several ways Various definitions of designing as pronounced by well-known designers are

ldquoDesign is that which defines solutions to problem which have previously been solved in a different wayrdquo

ldquo Design is the conscious human process of planning physical things that display a new form in response to some pre-determined needrdquo

ldquoDesign is an act of collecting all pertinent information for the production of goods and services to meet some human needrdquo

The design of any component includes two thingso Product design

o Process design

The product design involves the development of specification for a product that will be functionally sound good in appearance and will give satisfactory performance for an adequate life

The process design involves developing methods of manufacture of the products so that the component can be produced at a reasonably low cost

History of Design Process

o Design by Single Person

o Over-the-wall design

o Simultaneous Engineering

o Concurrent Engineering

o Integrated design and Manufacture

In olden times one person could design and manufacture an entire product Even for a large project such as the design of a ship or a bridge one person had sufficient knowledge of the Physics Materials and manufacturing processes to manage all aspects of the design and construction of the project This period is referred to as the period of design by single person in the history of design

By the middle of the 20th century products and manufacturing processes became so complex that one person could not handle all aspects of design and manufacturing This situation led to over-the-wall design process

In this method each functional departments were separated from others as shown by wall There was only one-way communications between Customer Marketing Engg Design and production department The customers lsquothrow their needs to marketing department The marketing department may throw the customer needs to the design department in many instances orally The Engg Design department may conceive a design and hands it over to the manufacturing sections The manufacturing department interprets that design and makes the product according to what they think suitable Unfortunately often what is manufactured by a company using over-the-wall process is not what the customers had in mind This is due to lack of interaction between the different departments Thus this

single direction over-the-wall approach is inefficient and costly and may result in poor quality products

By the early 1980s the concept of simultaneous engineering emerged This philosophy emphasized simultaneous development of the manufacturing process- the goal was the simultaneous development of the product and the manufacturing process This was accomplished by assigning manufacturing representatives to be members of design team so that they could interact with the design engineers throughout the designs processIn the 1980s the simultaneous design philosophy was broadened and called concurrent engineering A short definition of concurrent engineering is the simultaneous progression of all aspects at all stages of product development product specification design process and equipment etc In concurrent engineering the primary focus is on the integration of teams of people having a stake in the product design tools and techniques and information about the product and the processes used to develop and manufacture it Tools and techniques connect the teams with the information Although many of the tools are computer-based much design work is still done with pencil and paper In fact concurrent engineering is 80 company culture and 20 computer support

With the advent of computer technology drastic changes have taken place in the field of design and manufacturing The result was a completely integrated design and manufacturing system This system makes a good use of technologies such as CADCAM FMS etc The computer integrated manufacturing systems (CIMS) moves towards the lsquoFactory of the future CIMS is necessary for better quality efficiency and productivity

TYPES OF DESIGNS

The design can be classified in many ways On the basis of knowledge skill and creativity required in the designing process the designs are broadly classified into three types

Adaptive Design (W 95 97 98 lsquo00) Variant Design (S 97 99) Original Design

Adaptive Design

In most design situations the designers job is to make a slight modification of the existing design These are called adaptive designs This type of design needs no special knowledge or skill Eg converting mechanical watches into a new shape

Variant Design

This type of design demands considerable scientific training and design ability in order to modify the existing designs into a new idea by adopting a new material or a different method of manufacture In this case though the designer starts from the existing designs the final product may be entirely different from the original productEg converting mechanical watches into quartz watches Here a new technology is adopted

Original Design

Here the designer designs something that did not exist previously Thus it is also called new design or innovative design For making original designs a lot of research work knowledge and creativity are essential A company thinks of new design when there is a new technology available or when there is enough market push Since this type of design demands maximum creativity from the part of the designer these are also called creative designs

On the basis of the nature of design problem design may be classified as

o Selection design

o Configuration design

o Parametric design

o Original design

o Re-design

Selection Design

It involves choosing one or more items from a list of similar items We do this by using cataloguesEg -Selection of a bearing from a bearing catalogue-Selection of a fan for cooling equipment-Selecting a shaft Configuration Layout Packaging Design

In this type of problem all the components have been designed and the problem is how to assemble them into the completed product This type of design is similar to arranging furniture in a living room

Consider the packing of electronic components in a laptop computer A laptop computer has a keyboard power supply a main circuit board a hard disk drive a floppy disk drive and room for two extension boards Each component is of known design and has certain constraints on its position For example the extension slots must be adjacent to the main circuit board and the keyboard must be in front of the machine

Keyboard

Main Circuit board

Extension slots

Floppy drive Power supply

The different components are shown above The designers aim is to find how to fit all the components in a case Where do we put what One method for solving such problems is to ndash select a component randomly from the list and position it in the case so that all the constraints on that component are met

Lets take keyboard first It is placed in the front Then we select and place a second component This procedure is continued until we reach a conflict or all the components are in the case If a conflict arises we back up and try again Two potential configurations are shown above Parametric Design

Parametric design involves finding values for the features that characterize the object being studied

Consider a simple example ndashWe want to design a cylindrical storage tank that must hold 4 m 3 of liquidThe volume is given by

V = r 2 lThe tank is described by the parameters radius r and length l Given V = 4 m 3 = r 2 l

r 2 l = 1273We can see a number of values for the radius and length that will satisfy this

equation Each combination-values of r and l gives a possible solution for the design problem

Original Design

As described in an earlier section an original design in the development of an assembly or component that did not exist before

Redesign

The redesign is a modification of an existing product to meet new requirements It is same as adaptive design Most design problems solved in industry are for the redesign of an existing product Suppose a manufacturer of hydraulic cylinders makes a product that is 025m long If the customer needs a cylinder 03m long the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need

On the basis of the objective or strategy the designs are of following main types

o Production Design

o Functional Design

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

How can it be profitable

It must be easy to manufacture The raw material must be cheap and easily available The manufacturing process has to the decided on the basis of quantity to be

produced It must use standard parts It must be easy to pack and distribute

Definition of Design

Designing is such a vast field that it is defined in several ways Various definitions of designing as pronounced by well-known designers are

ldquoDesign is that which defines solutions to problem which have previously been solved in a different wayrdquo

ldquo Design is the conscious human process of planning physical things that display a new form in response to some pre-determined needrdquo

ldquoDesign is an act of collecting all pertinent information for the production of goods and services to meet some human needrdquo

The design of any component includes two thingso Product design

o Process design

The product design involves the development of specification for a product that will be functionally sound good in appearance and will give satisfactory performance for an adequate life

The process design involves developing methods of manufacture of the products so that the component can be produced at a reasonably low cost

History of Design Process

o Design by Single Person

o Over-the-wall design

o Simultaneous Engineering

o Concurrent Engineering

o Integrated design and Manufacture

In olden times one person could design and manufacture an entire product Even for a large project such as the design of a ship or a bridge one person had sufficient knowledge of the Physics Materials and manufacturing processes to manage all aspects of the design and construction of the project This period is referred to as the period of design by single person in the history of design

By the middle of the 20th century products and manufacturing processes became so complex that one person could not handle all aspects of design and manufacturing This situation led to over-the-wall design process

In this method each functional departments were separated from others as shown by wall There was only one-way communications between Customer Marketing Engg Design and production department The customers lsquothrow their needs to marketing department The marketing department may throw the customer needs to the design department in many instances orally The Engg Design department may conceive a design and hands it over to the manufacturing sections The manufacturing department interprets that design and makes the product according to what they think suitable Unfortunately often what is manufactured by a company using over-the-wall process is not what the customers had in mind This is due to lack of interaction between the different departments Thus this

single direction over-the-wall approach is inefficient and costly and may result in poor quality products

By the early 1980s the concept of simultaneous engineering emerged This philosophy emphasized simultaneous development of the manufacturing process- the goal was the simultaneous development of the product and the manufacturing process This was accomplished by assigning manufacturing representatives to be members of design team so that they could interact with the design engineers throughout the designs processIn the 1980s the simultaneous design philosophy was broadened and called concurrent engineering A short definition of concurrent engineering is the simultaneous progression of all aspects at all stages of product development product specification design process and equipment etc In concurrent engineering the primary focus is on the integration of teams of people having a stake in the product design tools and techniques and information about the product and the processes used to develop and manufacture it Tools and techniques connect the teams with the information Although many of the tools are computer-based much design work is still done with pencil and paper In fact concurrent engineering is 80 company culture and 20 computer support

With the advent of computer technology drastic changes have taken place in the field of design and manufacturing The result was a completely integrated design and manufacturing system This system makes a good use of technologies such as CADCAM FMS etc The computer integrated manufacturing systems (CIMS) moves towards the lsquoFactory of the future CIMS is necessary for better quality efficiency and productivity

TYPES OF DESIGNS

The design can be classified in many ways On the basis of knowledge skill and creativity required in the designing process the designs are broadly classified into three types

Adaptive Design (W 95 97 98 lsquo00) Variant Design (S 97 99) Original Design

Adaptive Design

In most design situations the designers job is to make a slight modification of the existing design These are called adaptive designs This type of design needs no special knowledge or skill Eg converting mechanical watches into a new shape

Variant Design

This type of design demands considerable scientific training and design ability in order to modify the existing designs into a new idea by adopting a new material or a different method of manufacture In this case though the designer starts from the existing designs the final product may be entirely different from the original productEg converting mechanical watches into quartz watches Here a new technology is adopted

Original Design

Here the designer designs something that did not exist previously Thus it is also called new design or innovative design For making original designs a lot of research work knowledge and creativity are essential A company thinks of new design when there is a new technology available or when there is enough market push Since this type of design demands maximum creativity from the part of the designer these are also called creative designs

On the basis of the nature of design problem design may be classified as

o Selection design

o Configuration design

o Parametric design

o Original design

o Re-design

Selection Design

It involves choosing one or more items from a list of similar items We do this by using cataloguesEg -Selection of a bearing from a bearing catalogue-Selection of a fan for cooling equipment-Selecting a shaft Configuration Layout Packaging Design

In this type of problem all the components have been designed and the problem is how to assemble them into the completed product This type of design is similar to arranging furniture in a living room

Consider the packing of electronic components in a laptop computer A laptop computer has a keyboard power supply a main circuit board a hard disk drive a floppy disk drive and room for two extension boards Each component is of known design and has certain constraints on its position For example the extension slots must be adjacent to the main circuit board and the keyboard must be in front of the machine

Keyboard

Main Circuit board

Extension slots

Floppy drive Power supply

The different components are shown above The designers aim is to find how to fit all the components in a case Where do we put what One method for solving such problems is to ndash select a component randomly from the list and position it in the case so that all the constraints on that component are met

Lets take keyboard first It is placed in the front Then we select and place a second component This procedure is continued until we reach a conflict or all the components are in the case If a conflict arises we back up and try again Two potential configurations are shown above Parametric Design

Parametric design involves finding values for the features that characterize the object being studied

Consider a simple example ndashWe want to design a cylindrical storage tank that must hold 4 m 3 of liquidThe volume is given by

V = r 2 lThe tank is described by the parameters radius r and length l Given V = 4 m 3 = r 2 l

r 2 l = 1273We can see a number of values for the radius and length that will satisfy this

equation Each combination-values of r and l gives a possible solution for the design problem

Original Design

As described in an earlier section an original design in the development of an assembly or component that did not exist before

Redesign

The redesign is a modification of an existing product to meet new requirements It is same as adaptive design Most design problems solved in industry are for the redesign of an existing product Suppose a manufacturer of hydraulic cylinders makes a product that is 025m long If the customer needs a cylinder 03m long the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need

On the basis of the objective or strategy the designs are of following main types

o Production Design

o Functional Design

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

o Design by Single Person

o Over-the-wall design

o Simultaneous Engineering

o Concurrent Engineering

o Integrated design and Manufacture

In olden times one person could design and manufacture an entire product Even for a large project such as the design of a ship or a bridge one person had sufficient knowledge of the Physics Materials and manufacturing processes to manage all aspects of the design and construction of the project This period is referred to as the period of design by single person in the history of design

By the middle of the 20th century products and manufacturing processes became so complex that one person could not handle all aspects of design and manufacturing This situation led to over-the-wall design process

In this method each functional departments were separated from others as shown by wall There was only one-way communications between Customer Marketing Engg Design and production department The customers lsquothrow their needs to marketing department The marketing department may throw the customer needs to the design department in many instances orally The Engg Design department may conceive a design and hands it over to the manufacturing sections The manufacturing department interprets that design and makes the product according to what they think suitable Unfortunately often what is manufactured by a company using over-the-wall process is not what the customers had in mind This is due to lack of interaction between the different departments Thus this

single direction over-the-wall approach is inefficient and costly and may result in poor quality products

By the early 1980s the concept of simultaneous engineering emerged This philosophy emphasized simultaneous development of the manufacturing process- the goal was the simultaneous development of the product and the manufacturing process This was accomplished by assigning manufacturing representatives to be members of design team so that they could interact with the design engineers throughout the designs processIn the 1980s the simultaneous design philosophy was broadened and called concurrent engineering A short definition of concurrent engineering is the simultaneous progression of all aspects at all stages of product development product specification design process and equipment etc In concurrent engineering the primary focus is on the integration of teams of people having a stake in the product design tools and techniques and information about the product and the processes used to develop and manufacture it Tools and techniques connect the teams with the information Although many of the tools are computer-based much design work is still done with pencil and paper In fact concurrent engineering is 80 company culture and 20 computer support

With the advent of computer technology drastic changes have taken place in the field of design and manufacturing The result was a completely integrated design and manufacturing system This system makes a good use of technologies such as CADCAM FMS etc The computer integrated manufacturing systems (CIMS) moves towards the lsquoFactory of the future CIMS is necessary for better quality efficiency and productivity

TYPES OF DESIGNS

The design can be classified in many ways On the basis of knowledge skill and creativity required in the designing process the designs are broadly classified into three types

Adaptive Design (W 95 97 98 lsquo00) Variant Design (S 97 99) Original Design

Adaptive Design

In most design situations the designers job is to make a slight modification of the existing design These are called adaptive designs This type of design needs no special knowledge or skill Eg converting mechanical watches into a new shape

Variant Design

This type of design demands considerable scientific training and design ability in order to modify the existing designs into a new idea by adopting a new material or a different method of manufacture In this case though the designer starts from the existing designs the final product may be entirely different from the original productEg converting mechanical watches into quartz watches Here a new technology is adopted

Original Design

Here the designer designs something that did not exist previously Thus it is also called new design or innovative design For making original designs a lot of research work knowledge and creativity are essential A company thinks of new design when there is a new technology available or when there is enough market push Since this type of design demands maximum creativity from the part of the designer these are also called creative designs

On the basis of the nature of design problem design may be classified as

o Selection design

o Configuration design

o Parametric design

o Original design

o Re-design

Selection Design

It involves choosing one or more items from a list of similar items We do this by using cataloguesEg -Selection of a bearing from a bearing catalogue-Selection of a fan for cooling equipment-Selecting a shaft Configuration Layout Packaging Design

In this type of problem all the components have been designed and the problem is how to assemble them into the completed product This type of design is similar to arranging furniture in a living room

Consider the packing of electronic components in a laptop computer A laptop computer has a keyboard power supply a main circuit board a hard disk drive a floppy disk drive and room for two extension boards Each component is of known design and has certain constraints on its position For example the extension slots must be adjacent to the main circuit board and the keyboard must be in front of the machine

Keyboard

Main Circuit board

Extension slots

Floppy drive Power supply

The different components are shown above The designers aim is to find how to fit all the components in a case Where do we put what One method for solving such problems is to ndash select a component randomly from the list and position it in the case so that all the constraints on that component are met

Lets take keyboard first It is placed in the front Then we select and place a second component This procedure is continued until we reach a conflict or all the components are in the case If a conflict arises we back up and try again Two potential configurations are shown above Parametric Design

Parametric design involves finding values for the features that characterize the object being studied

Consider a simple example ndashWe want to design a cylindrical storage tank that must hold 4 m 3 of liquidThe volume is given by

V = r 2 lThe tank is described by the parameters radius r and length l Given V = 4 m 3 = r 2 l

r 2 l = 1273We can see a number of values for the radius and length that will satisfy this

equation Each combination-values of r and l gives a possible solution for the design problem

Original Design

As described in an earlier section an original design in the development of an assembly or component that did not exist before

Redesign

The redesign is a modification of an existing product to meet new requirements It is same as adaptive design Most design problems solved in industry are for the redesign of an existing product Suppose a manufacturer of hydraulic cylinders makes a product that is 025m long If the customer needs a cylinder 03m long the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need

On the basis of the objective or strategy the designs are of following main types

o Production Design

o Functional Design

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

single direction over-the-wall approach is inefficient and costly and may result in poor quality products

By the early 1980s the concept of simultaneous engineering emerged This philosophy emphasized simultaneous development of the manufacturing process- the goal was the simultaneous development of the product and the manufacturing process This was accomplished by assigning manufacturing representatives to be members of design team so that they could interact with the design engineers throughout the designs processIn the 1980s the simultaneous design philosophy was broadened and called concurrent engineering A short definition of concurrent engineering is the simultaneous progression of all aspects at all stages of product development product specification design process and equipment etc In concurrent engineering the primary focus is on the integration of teams of people having a stake in the product design tools and techniques and information about the product and the processes used to develop and manufacture it Tools and techniques connect the teams with the information Although many of the tools are computer-based much design work is still done with pencil and paper In fact concurrent engineering is 80 company culture and 20 computer support

With the advent of computer technology drastic changes have taken place in the field of design and manufacturing The result was a completely integrated design and manufacturing system This system makes a good use of technologies such as CADCAM FMS etc The computer integrated manufacturing systems (CIMS) moves towards the lsquoFactory of the future CIMS is necessary for better quality efficiency and productivity

TYPES OF DESIGNS

The design can be classified in many ways On the basis of knowledge skill and creativity required in the designing process the designs are broadly classified into three types

Adaptive Design (W 95 97 98 lsquo00) Variant Design (S 97 99) Original Design

Adaptive Design

In most design situations the designers job is to make a slight modification of the existing design These are called adaptive designs This type of design needs no special knowledge or skill Eg converting mechanical watches into a new shape

Variant Design

This type of design demands considerable scientific training and design ability in order to modify the existing designs into a new idea by adopting a new material or a different method of manufacture In this case though the designer starts from the existing designs the final product may be entirely different from the original productEg converting mechanical watches into quartz watches Here a new technology is adopted

Original Design

Here the designer designs something that did not exist previously Thus it is also called new design or innovative design For making original designs a lot of research work knowledge and creativity are essential A company thinks of new design when there is a new technology available or when there is enough market push Since this type of design demands maximum creativity from the part of the designer these are also called creative designs

On the basis of the nature of design problem design may be classified as

o Selection design

o Configuration design

o Parametric design

o Original design

o Re-design

Selection Design

It involves choosing one or more items from a list of similar items We do this by using cataloguesEg -Selection of a bearing from a bearing catalogue-Selection of a fan for cooling equipment-Selecting a shaft Configuration Layout Packaging Design

In this type of problem all the components have been designed and the problem is how to assemble them into the completed product This type of design is similar to arranging furniture in a living room

Consider the packing of electronic components in a laptop computer A laptop computer has a keyboard power supply a main circuit board a hard disk drive a floppy disk drive and room for two extension boards Each component is of known design and has certain constraints on its position For example the extension slots must be adjacent to the main circuit board and the keyboard must be in front of the machine

Keyboard

Main Circuit board

Extension slots

Floppy drive Power supply

The different components are shown above The designers aim is to find how to fit all the components in a case Where do we put what One method for solving such problems is to ndash select a component randomly from the list and position it in the case so that all the constraints on that component are met

Lets take keyboard first It is placed in the front Then we select and place a second component This procedure is continued until we reach a conflict or all the components are in the case If a conflict arises we back up and try again Two potential configurations are shown above Parametric Design

Parametric design involves finding values for the features that characterize the object being studied

Consider a simple example ndashWe want to design a cylindrical storage tank that must hold 4 m 3 of liquidThe volume is given by

V = r 2 lThe tank is described by the parameters radius r and length l Given V = 4 m 3 = r 2 l

r 2 l = 1273We can see a number of values for the radius and length that will satisfy this

equation Each combination-values of r and l gives a possible solution for the design problem

Original Design

As described in an earlier section an original design in the development of an assembly or component that did not exist before

Redesign

The redesign is a modification of an existing product to meet new requirements It is same as adaptive design Most design problems solved in industry are for the redesign of an existing product Suppose a manufacturer of hydraulic cylinders makes a product that is 025m long If the customer needs a cylinder 03m long the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need

On the basis of the objective or strategy the designs are of following main types

o Production Design

o Functional Design

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

The design can be classified in many ways On the basis of knowledge skill and creativity required in the designing process the designs are broadly classified into three types

Adaptive Design (W 95 97 98 lsquo00) Variant Design (S 97 99) Original Design

Adaptive Design

In most design situations the designers job is to make a slight modification of the existing design These are called adaptive designs This type of design needs no special knowledge or skill Eg converting mechanical watches into a new shape

Variant Design

This type of design demands considerable scientific training and design ability in order to modify the existing designs into a new idea by adopting a new material or a different method of manufacture In this case though the designer starts from the existing designs the final product may be entirely different from the original productEg converting mechanical watches into quartz watches Here a new technology is adopted

Original Design

Here the designer designs something that did not exist previously Thus it is also called new design or innovative design For making original designs a lot of research work knowledge and creativity are essential A company thinks of new design when there is a new technology available or when there is enough market push Since this type of design demands maximum creativity from the part of the designer these are also called creative designs

On the basis of the nature of design problem design may be classified as

o Selection design

o Configuration design

o Parametric design

o Original design

o Re-design

Selection Design

It involves choosing one or more items from a list of similar items We do this by using cataloguesEg -Selection of a bearing from a bearing catalogue-Selection of a fan for cooling equipment-Selecting a shaft Configuration Layout Packaging Design

In this type of problem all the components have been designed and the problem is how to assemble them into the completed product This type of design is similar to arranging furniture in a living room

Consider the packing of electronic components in a laptop computer A laptop computer has a keyboard power supply a main circuit board a hard disk drive a floppy disk drive and room for two extension boards Each component is of known design and has certain constraints on its position For example the extension slots must be adjacent to the main circuit board and the keyboard must be in front of the machine

Keyboard

Main Circuit board

Extension slots

Floppy drive Power supply

The different components are shown above The designers aim is to find how to fit all the components in a case Where do we put what One method for solving such problems is to ndash select a component randomly from the list and position it in the case so that all the constraints on that component are met

Lets take keyboard first It is placed in the front Then we select and place a second component This procedure is continued until we reach a conflict or all the components are in the case If a conflict arises we back up and try again Two potential configurations are shown above Parametric Design

Parametric design involves finding values for the features that characterize the object being studied

Consider a simple example ndashWe want to design a cylindrical storage tank that must hold 4 m 3 of liquidThe volume is given by

V = r 2 lThe tank is described by the parameters radius r and length l Given V = 4 m 3 = r 2 l

r 2 l = 1273We can see a number of values for the radius and length that will satisfy this

equation Each combination-values of r and l gives a possible solution for the design problem

Original Design

As described in an earlier section an original design in the development of an assembly or component that did not exist before

Redesign

The redesign is a modification of an existing product to meet new requirements It is same as adaptive design Most design problems solved in industry are for the redesign of an existing product Suppose a manufacturer of hydraulic cylinders makes a product that is 025m long If the customer needs a cylinder 03m long the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need

On the basis of the objective or strategy the designs are of following main types

o Production Design

o Functional Design

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

o Selection design

o Configuration design

o Parametric design

o Original design

o Re-design

Selection Design

It involves choosing one or more items from a list of similar items We do this by using cataloguesEg -Selection of a bearing from a bearing catalogue-Selection of a fan for cooling equipment-Selecting a shaft Configuration Layout Packaging Design

In this type of problem all the components have been designed and the problem is how to assemble them into the completed product This type of design is similar to arranging furniture in a living room

Consider the packing of electronic components in a laptop computer A laptop computer has a keyboard power supply a main circuit board a hard disk drive a floppy disk drive and room for two extension boards Each component is of known design and has certain constraints on its position For example the extension slots must be adjacent to the main circuit board and the keyboard must be in front of the machine

Keyboard

Main Circuit board

Extension slots

Floppy drive Power supply

The different components are shown above The designers aim is to find how to fit all the components in a case Where do we put what One method for solving such problems is to ndash select a component randomly from the list and position it in the case so that all the constraints on that component are met

Lets take keyboard first It is placed in the front Then we select and place a second component This procedure is continued until we reach a conflict or all the components are in the case If a conflict arises we back up and try again Two potential configurations are shown above Parametric Design

Parametric design involves finding values for the features that characterize the object being studied

Consider a simple example ndashWe want to design a cylindrical storage tank that must hold 4 m 3 of liquidThe volume is given by

V = r 2 lThe tank is described by the parameters radius r and length l Given V = 4 m 3 = r 2 l

r 2 l = 1273We can see a number of values for the radius and length that will satisfy this

equation Each combination-values of r and l gives a possible solution for the design problem

Original Design

As described in an earlier section an original design in the development of an assembly or component that did not exist before

Redesign

The redesign is a modification of an existing product to meet new requirements It is same as adaptive design Most design problems solved in industry are for the redesign of an existing product Suppose a manufacturer of hydraulic cylinders makes a product that is 025m long If the customer needs a cylinder 03m long the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need

On the basis of the objective or strategy the designs are of following main types

o Production Design

o Functional Design

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Extension slots

Floppy drive Power supply

The different components are shown above The designers aim is to find how to fit all the components in a case Where do we put what One method for solving such problems is to ndash select a component randomly from the list and position it in the case so that all the constraints on that component are met

Lets take keyboard first It is placed in the front Then we select and place a second component This procedure is continued until we reach a conflict or all the components are in the case If a conflict arises we back up and try again Two potential configurations are shown above Parametric Design

Parametric design involves finding values for the features that characterize the object being studied

Consider a simple example ndashWe want to design a cylindrical storage tank that must hold 4 m 3 of liquidThe volume is given by

V = r 2 lThe tank is described by the parameters radius r and length l Given V = 4 m 3 = r 2 l

r 2 l = 1273We can see a number of values for the radius and length that will satisfy this

equation Each combination-values of r and l gives a possible solution for the design problem

Original Design

As described in an earlier section an original design in the development of an assembly or component that did not exist before

Redesign

The redesign is a modification of an existing product to meet new requirements It is same as adaptive design Most design problems solved in industry are for the redesign of an existing product Suppose a manufacturer of hydraulic cylinders makes a product that is 025m long If the customer needs a cylinder 03m long the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need

On the basis of the objective or strategy the designs are of following main types

o Production Design

o Functional Design

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Parametric design involves finding values for the features that characterize the object being studied

Consider a simple example ndashWe want to design a cylindrical storage tank that must hold 4 m 3 of liquidThe volume is given by

V = r 2 lThe tank is described by the parameters radius r and length l Given V = 4 m 3 = r 2 l

r 2 l = 1273We can see a number of values for the radius and length that will satisfy this

equation Each combination-values of r and l gives a possible solution for the design problem

Original Design

As described in an earlier section an original design in the development of an assembly or component that did not exist before

Redesign

The redesign is a modification of an existing product to meet new requirements It is same as adaptive design Most design problems solved in industry are for the redesign of an existing product Suppose a manufacturer of hydraulic cylinders makes a product that is 025m long If the customer needs a cylinder 03m long the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need

On the basis of the objective or strategy the designs are of following main types

o Production Design

o Functional Design

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

o Optimum Design

1 Production Design

In production design the designer designs something in such a way that the cost of producing the product is minimum That is the first responsibility of the designer is reduction of production cost Hence a production designer is concerned with the ease with which something can be produced and that at a minimum cost

2 Functional Design

In functional design the aim is at designing a part or member so as to meet the expected performance level

Functional design is a way of achieving given requirements- but the same may the unproducible or costly to produce A good designer then has to consider the production aspects also A product designed without keeping all these aspects into account wastes time money and efforts

3 Optimum Design

It is the best design for given objective function under the specified constraints

On the basis of the field area or the domain of design the following types are important

Mechanical Design Machine Design System Design Assemblysub-assembly design Computer aided design

A Mechanical Design

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

It means use of scientific principles technical information and imagination in the design of a structureor machine to perform prescribed functions with maximum economy and efficiency

B Machine Design

It is the process of achieving a plan for the construction of a machine

C System Design

System Design is an iterative decision making process to conceive and implement optimum systems to solve problems and needs of society

D Assemblysub-assembly design

In the design of Assemblysub-assembly the major criterion is the fulfillment of functional requirements The assembly has to be designed to meet broad technical parameters and purpose for which it was meant

The characteristic features are The total number of parts used in the design must be minimum Sub-assemblies should be capable of being built separately in order to give

maximum manufacturing flexibility Standard parts may be used Flexible parts should be avoided as they are easily damaged during handling

and assembly

E Computer aided design [CAD]

It is a design methodology in which the designs take the advantages of digital computer to draw concepts analyze and evaluate data etc Computers are largely used in a design office for simulation and prototype study In modern design computers have become an indispensable tool

Other types of designs are

a Probabilistic Design

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

b Industrial Design

A Probabilistic Design

It is a design approach in which design decisions are made using statistical tools Generally the external load acting on a body the properties of materials etc are liable to vary In probabilistic design the designer takes into account the variations of such parameters

B Industrial Design

It is the design made by considering aesthetes ergonomics and production aspects Questions

1 What are the characteristics features of system design assemblysub-assembly design and component design Explain briefly with the help of examples

2 Distinguish between functional design and industrial design 3 Discuss the meanings of conceptual design creative design adoptive

design and variant design 4 What are the three main types of design Give a comparative analysis5 Explain the difference between creative design adoptive design and

variant design 6 Explain the meaning of (i) Conceptual design (ii) Functional design and

(iii) production design Give suitable example of each 7 Explain layout design

DESIGN PROCESS AND ITS STRUCTURES Introduction

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Developing a manufacturable product is not an easy job This chapter presents some methods that help achieve quality products Rather than making a detailed study only an overview of designing process is attempted here

Features of design process

The following features can be observed in a design process Iteration Decision-making Conversion of resources Satisfaction of need

Design is completed in many phases In each phase repeated attempts are required to accomplish the aim A satisfactory conclusion can be reached on only after a number of trialsDecision-making is essential for a designer to select one out of several A designer often comes across several equally acceptable alternatives to meet some end In such conflicting situations designer has to make the best decision

In any design process there is conversion of resources such as time money talent materials and other natural resources

All designs are aimed at satisfying some human need Needs whether important or unimportant is the starting point of design

How a design is born

In a broad sense there are two methods by which a design comes into existence

Design by evolution (Traditional Design) Design by innovation (Modern Design)

1 Design by evolution

This implies the traditional method of design in which the objects and articles that we see around has taken its present form by gradual change of time If one looks at history it can be seen that most of the tools equipments implements

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

took a long time to acquire their present form Things changed gradually with the passage of time Each change was made to rectify some defects or difficulties faced by the users Bicycles calculators computers steam locomotives etc all went through a process of evolution in which designers tried one concept after another Even today this process is being used to some extent However this evolutionary process is very slow ie it took a very long period of time to occur even a slight modification The main reason for this slow evolutionary process of design was the absence of proper information and design data records

In modern design situations the evolutionary methods are not adequate because of the following reasons

The traditional designing did not consider the interdependence of products They were concerned about only one component product But in the modern world the existence of one product is dependent on another in some way or other

In the past production was on small scale Thus the penalty of a wrong design was tolerable But in the present time production is on large-scale basis As a result any penalty of a wrong design will cost great loss

Requirements of the customers of todays world changes so frequently Traditional design lags behind the advanced product amp process technologies available today

Traditional design methods cannot cope with competitive requirements of the modern world

Due to the above reasons modern design problem cannot be handled by traditional methods

2 Design by Innovation

Since the traditional design method failed to cope with modern design requirements nowadays almost all designs are made by innovation ie developments of a product by following scientific and purposeful effortThe innovative design is entirely different from the past practice of evolutionary design Here the designers task is greatly magnified He has to design and create something which did not exist yet Here he tries to solve the design problem in a

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

systematic and orderly manner This approach is similar to analytical problem solving However an innovative designer faces the following difficulties

He has to collect and evaluate information on a product which is non-existing yet

Necessity of analyzing complicated interaction of components He has to make predictions regarding its performance He has to ensure the technical and economical feasibility of the product

Notwithstanding the above difficulties there are eminent experts like Morris Asimow JE Shigly Dieter etc have attempted to systematize the design process This systematized steps in design process is called Morphology of Design The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method This approach of problem solving is also adopted in the Morphology of design

3 Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem

Establish or convince ourselves that there lsquois a problem Or we understand that a solution is needed

Plan how to solve this problem By analyzing the problem we decide what is actually required from the

problem-solver Or we decide the requirements Generate alternative solutions Evaluate the alternatives Present the acceptable solution

10 DESIGN PROCESS

The design process is illustrated by the following models namely Shigley Paul and Beitz Ohsuga and Earle

11 Shighely Model

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

In the design process there are six steps to be followed which are shown in fig 15

Recognition of need The problems in the existing products (or) Potential for new products in

market has to be identified

Definition of problem The problem in the existing product or specification of the new product is

specified as ldquoDesign Briefrdquo to the designers It includes the specification of physical and functional characteristics cost quality performance requirements etc

Fig 11 The general design procedure defined by Shigley SynthesisIn this stage the designer develops number of designs to meet the

requirement of design brief

Analysis amp Optimization Each design from the synthesis stages are analysed and optimum one is

selected

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

It should be noted that synthesis and analysis are highly iterative A certain component or subsystem of the overall system conceived by the designer in the synthesis stage is subjected to analysis

Based on the analysis improvements are made and redesigned The process is repeated until the design optimized within all the constraints imposed by designer

Evaluation In this stage optimized design from the previous stage is checked for all the

specification mentioned in the ldquoDesign Briefrdquo A prototype of the product is developed and experimentally checked for its

performance quality reliability and other aspects of product The discrepanciesproblems are faced it is recommend to redesign the

product which should be fed back to the designer in the synthesis stage

PresentationAfter the product design passing through the evaluation stage drawings

diagrams material specification assembly lists bill of materials etc which are required for product manufacturing are prepared and given to process planning department and production department

12 Earle model

The steps in the design process prepared by Earle are shown in fig12 Problem identification

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Fig 12 Steps of design process by Earle(1) Problem identification

The problem identification can be one of two general types(i) Identification of need(ii) Identification of design criteriaIdentification of need is the beginning point of the design process It may be

a defect or discrepancy in the existing product or need for a new product

Identification of design criteria is the part of the problem identification where the designer conducts an in-depth investigation of the specifications that must be met by a new design Types of problem identification are shown in fig 19

Types of problem identification

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Fig 13 Type of problem identification

The problem identification needs to gather data of several types Such as survey historical records personal observations experimental data physical measurements etc

The following steps should be used in problem identification

Fig 13 Steps followed in problem identification

(a) Problem statement write down the problem statement to begin the thinking process The statement should be complete and comprehensive but concise

(b) Problem requirements list the positive requirements that must be achieved through design

(c) Problem limitations list negative factors that confine the problem to be specified as limitations

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

(d) Sketches make sketches of physical characteristics of the problem Add notes and dimensions that would make these sketches more understandable(e) Gather data the gathered data should be graphed for easy interpretation

(u) Preliminary ideasPreliminary ideas are the generation of as many ideas as possible for

solution These ideas should be sufficiently broad to allow for unique solutions that could revolutionize present methods All ideas should be recorded in written form with sketches A systematic approach should be used to gather preliminary ideas for the design problem The following sequence of steps is suggested

Design need1 Defects2 Bad condition3Need for solution4 Market needDesign criteria1 Features2 Numbers3 Size-weight4 Price cost

Problem identification

(a) Conduct brain stroming session Brainstrom is a conference technique by which a group attempts to find a solution for a specific problem by amassing all the ideas spontaneously contributed by its members

(b) Prepare sketches and notes Sketching is most important medium for developing preliminary ideas Computer graphics can be used for modifying and developing a number of ideas

(c) Research existing designs Preliminary ideas can be obtained through research of similar products designs from technical magazines manufacturer1048758 s brochures patents and consultants

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

(d) Conduct survey Survey methods are used to gather opinions and reactions to a preliminary design or complete design This could be accomplished by interviews questionnaire etc

(iii) Design refinementSeveral of better preliminary ideas are selected for further refinement to

determine their true merits Rough sketches are converted to scale drawings that will permit space analysis critical measurements etc descriptive geometry can be applied for this purpose Computer graphics is a powerful tool that can be used to refine the preliminary idea

(iv) AnalysisA product must be analyzed to determine its acceptance by the market

before it is released for production It involves the evaluation of best designs to determine the comparative merits of each with respect to cost strength function and market-appealThe general areas of analysis are

(a) Functional analysis(b) Human engineering(c) Market and product analysis(d) Specification analysis(e) Strength analysis(f) Economic analysis(g) Model analysis

The physical specifications of a product must be analyzed to finalize the design Eg size ranges and shipping specifications The design must be analyzed for strength to support dead loads shock loads fatigue loads etc The cost analysis must be performed to determine the itemrsquos production cost and margin of profit that can be realized from it Engineering graphics and modeling of descriptive geometry are valuable tools for analysis

12 MORPHOLOGY OF DESIGN

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Evaluate

OutcomeDesignProcess

GeneralInformation

SpecificInformation

NO YES

The morphology of design refers to the study of the chronological structure of design projects It is defined by seven phases and their sub steps Out of the seven phases the first three phases belong to design and the remaining four phases belong to production distribution consumption and retirement

Morphology means lsquoa study of form or structure Morphology of design refers to the time based sequencing of design operations It is a methodology of design by which ideas about things are converted into physical objects The logical order of different activities or phases in a design project is called the morphology of design

Morphology of design

ndash Detailed description of the complete design process

The design Process

Phase I Conceptual Design

o It requires the creativity

o Single best concept feasibility study

o Coordination among many functions in the business organizations

bull Identification of customer needsbull Problem definition

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Problem Statement Benchmarking Quality Function Deployment (QFD) Product Design Specification (PDS)

bull Gathering information Internet Patents Trade Literature

bull Conceptualization Brainstorming Functional Decomposition Morphological Chart

bull Concept selection Pugh Concept Selection Decision Matrix

bull Refinement of the PDSbull Design review

A design project begins with a feasibility study The various steps followed are(1) To determine whether the need is original whether it is valid has current

existence or has strong evidence of latent existence(2) To explore the design problem generated by the need and to identify its

elements such as working parameters constraints and major design criteria(3) To conceive a number of feasible solutions to the problem(4) And sort out the potentially useful solution out of the feasible ones on the

basis of

(a) Technical suitability (b) Physical reliability and (c) Economic feasibility

Phase II Embodiment design or preliminary design

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

- Strength material selection size shape and spatial compatibility

bull Product architecture Dividing overall design system into sub system or

modules Arrangement of Physical Elements to carry out Function

bull Configuration design of parts and components Preliminary Selection of Parts and Materials Modeling and Sizing of Parts Parts are made up of features like holes ribs splines and

curves To determine what features will be present amphow those

features are arranged in spacebull Parametric design To establish the exact dimensions and tolerances

Robust Design Tolerances Final Dimensions Design for Manufacturability (DFM)

In this phase preliminary design of system starts with set of useful solution which were developed in the feasibility study The various steps involved in the phase are

(1) To establish which of the proposed alternatives is the best design concept Each of the alternative design is subjected to the test of analysis Until evidence suggests that either the particular solution is inferior to other or is superior to all Surviving solution is tentatively accepted for further examination

(2) Synthesis studies are initiated for establishing the range within which the major design parameters must be controlled

(3) Next the tolerances in the characteristics of major components and critical materials which require mutual compatibility are investigated and properly fit into the system

(4) Examining the influence of environmental internal and external constituents on the system

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Define Problem

Problem StatementBenchmarking

QFD PDS

Gathering information

InternetPatentsTrade

Literature

Concept GenerationBrainstorming

FunctionalDecomposition

Morphological Chart

Evaluation of concepts

Pugh Concept Selection

Decision Matrix

Product architecture

Arrangement of physical elements to

carry out function

Configuration design

Preliminary Selection matls amp

mfgModelingsizing

Parametric design

Robust designTolerances

Final dimenDFM

Detail Design

Detailed drawings and specifications

(5) Project studies are undertaken to study whether the design will meet customers need status of the product to be developed with that of products from competitors availability of critical raw materials effect of technological advancement rate of obsolescence or wear etc

(6) Testing the critical aspect of the design in order to validate the design concept and to provide necessary information for the subsequent phases

Phase III Detail Design

In this phase the engineering description of a tested and producible design is furnished Up to this point the design project is characterized by great flexibility Major changes in the concept could be accommodated with out of greater financial loss But in this stage searching on a large scale must come to an end and a final decision for a particular design can be made or the project must be abandoned as infeasible The various steps taken in this design phases are

(1) Developing an overall synthesis of the design project and preparing a major layout of the system

(2) Preparing specifications of various sub systems and components on the basis of master layout

(3) Deciding various dimensions of components

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

(4) Initiating the experiment design by constructing to check untried ideas Complete engineering description of a tested and producible product Form dimensions tolerances properties materials and manufacturing

process of each part Engineering drawings ampcomputer generated drawings-determine assembly

drg Before the information passed on to manufacturing

Phase IV Planning For Manufacture

ndash Process sheet establishedndash List of manufacturing operations that must be performed on the

componentbull It specifies the form and condition of material and tooling ampproduction

mcrsquosbull Estimation of production cost of the component

Designing specialized tools and fixtures Specify production plant to be used Planning the work schedules amp inventory control Planning the quality assurance system Establishing the standard time and labor cost for each operation Establish the system of information flow

Phase V Planning For Distribution

Effective distribution to the consumer of the system Marketing advertising and news media techniques Shipping Package Documentation Shelf Life Warehouses

After production of the products the products have to be distributed Designers are not directly involved in the distribution activities His job is finding the problems of distribution and getting solution for these problems

In this phase a plan on effective and flexible system of distribution of designed goods Some of the activities which are carried out in this phase are

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

(1) Design the packaging of the product Based on the outer shape of the product packaging system will be

developed such a way that the transportation cost will be minimum and safe

Individual and special packaging may be needed to secure protection from shock and weather

Special strapping and palletizing arrangement may be developed to facilitate handling

(2) Planning the ware housing system

Economically favorable locations for warehouse are selected and the warehousing facilities are designed

(3) Planning for promotional activity brochures Technical phamplets displays based on design features and

test data have to be developed

(4) Factors such as attractive display additional attachment features and final conditioning

There should be enough flexibility in design to allow(a) for special modifications to suit customers need(b) for adding available optional feature as required by the customer(c) for modular additions to the system to increase its capacity

Phase VI Planning For Use

Consumption is the third phase in the production-consumption cycle Its influence on design is very high compare to the other phase of design

In design for consumption the following factors must be considered

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

(1) Design for maintenance(2) Design for reliability(3) Design for safety(4) Design for convenience of use(5) Design for economic operation(6) Design for aesthetic features(7) Design for adequate duration of services(8) Product improvement based on the service data

User oriented design process Ease of maintenance reliability safety aesthetic appeal economy

of operation duration of service

Phase VII Planning For Retirement Of The Product

ndash Disposal of the product end of its useful lifendash Green design-recycling of materials remanufacture

Useful Life

o Deterioration

o Technical Obsolescence

o Fashion or Taste

o Environmental Issues

Industrial Ecology Green Design

o RFI

o Power Consumption

Detailed Morphology of Design

A design project goes through a number of time phases Morphology of design refers to the collection of these time phases The morphology of design as put forward by Morris Asimow can be elaborated as given below It consists of seven phases

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

1 Feasibility Study

This stage is also called conceptual design A design project always begins with a feasibility study The purpose and activities during feasibility study are

To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences rather than the outcome of ones fancy]

Search for a number of possible solutions Evaluate the solutions

ie is it physically realisableIs it economically worthwhileIs it within our financial capacity

2 Preliminary (Embodiment) Design

This is the stage art which the concept generated in the feasibility study is carefully developed The important activities done at this stage are

Model building amp testing Study the advantages and disadvantages of different solutions Check for performance quality strength aesthetics etc

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

3 Detail Design

Its purpose is to furnish the complete engineering description of the tested product The arrangement from dimensions tolerances and surface properties of all individual parts are determined Also the materials to be used and the manufacturing process to be adopted etc are decided Finally complete prototype is tested

4 Planning for manufacture

This phase includes all the production planning and control activities necessary for the manufacture of the product The main tasks at this phase are

Preparation of process sheet ie the document containing a sequential list of manufacturing processes

Specify the condition of row materials Specify tools amp machine requirements Estimation of production cost Specify the requirement in the plant Planning QC systems Planning for production control Planning for information flow system etc

5 Planning for Distribution

The economic success of a design depends on the skill exercised in marketing Hence this phase aims at planning an effective distribution system Different activities of this phase are

Designing the packing of the product Planning effective and economic warehousing systems Planning advertisement techniques Designing the product for effective distribution in the prevailing conditions

6 Planning for Consumptionuse

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

The purpose of this phase is to incorporate in the design all necessary user- oriented features The various steps are

Design for maintenance Design for reliability Design for convenience in use Design for aesthetic features Design for prolonged life Design for product improvement on the basis of service data

7 Planning for Retirement

This is the phase that takes into account when the product has reached the end of useful life A product may retire when

It does not function properly Another competitive design emerges Changes of taste or fashion

The various steps in this phase are Design for several levels of use Design to reduce the rate of obsolescence Examine service-terminated products to obtain useful information

METHODS OF INNOVATIVE DESIGN

As we know innovative design is an organized systematized and logical approach for solving a design problem There are two design methods for innovative design

1 Design by creative design route2 Engineering Design

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

1 Design by creative routs [Creative Design]

This is a design method that demands maximum lsquocreativity from the part of the designer Hence this method is also called creative design Here the designer finds solutions to problems by allowing his creativity aspects grow in a particular manner

A Creativity

Majority of designs belong to variant design where the designer simply modifies an existing system But the success of engineering design depends on the modes of thinking and acting distinctively different from others A creative designer is distinguished by his ability to synthesize new combinations of ideas and concepts into meaningful and useful forms Design is commonly thought of as a creative process involving the use of imagination and lateral thinking to create new and different products

B Qualities of a creative designer

The creative designer is generally a person of average intelligence a visualiser a hard worker and a constructive non-conformist with average knowledge about the problem at handGenerally a creative designer has the following qualities

Visualization abilityCreative designers have good ability to visualize to generate and

manipulate visual images in their heads

KnowledgeAll designers start their job with what they know During designing

they make minor modifications of what they already know ndashor creative designers create new ideas out of bits of old designs they had seen in the past Hence they must have knowledge of past designs

Ability to manipulate knowledge

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

The ability to use the same knowledge in a different way is also an important quality of a designer

Risk takingA person who does not take the risk of making mistakes cannot

become a good designer For example Edison tried hundreds of different light bulb designs before he found the carbon filament

Non-conformistThere are two types of non-conformists-constructive and obstructive

Constructive non-conformists are those who take a firm stand because they think they are right Obstructive non-conformists are those who take a stand just to have an opposing view The constructive non-conformists might generate a good idea But the obstructive non-conformists will only slow down the design process Creative designers are constructive non-conformists and they want to do things in their own way

TechniqueCreative designers have more than one approach to problem solving

They are prepared to try alternative techniques till they reach a satisfactory solution

MotivationThey always motivate others in the design team In such a favourable

environment creativity is further enhanced

Willingness to practiceCreativity comes with practice Creative designers are ready to practice for a long enough period

2 Roadblocks to Creativity

Fear of making a mistake Unwillingness to think and act in a way other than the accepted norm Desire to conform to standard solutions

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Unwillingness to try new approaches Fear of criticism Lack of knowledge Overconfidence due to past experience Unwillingness to reject old solutions Fear of authority Difficulty in visualization Inability to distinguish between cause and effect Inability to collect complete information Unwillingness to be different

3 Methods to enhance Creativity

Use of analogy Asking question from different view points Memories of past designs Competitive products Deliberate day-dreaming Reading science fictions etc

4 Intuition

Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas elaborated in subconscious mind Intuitive ideas lead to a large number of good and even excellent solutions

5 Creative Design Route

Creative design route is the procedure through which a creative design is born The success of this design lies with the creativity of the designer Creative design route can be practiced by following the sequences shown in figure

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

a Preparation

During preparation period the designer analyses the need and collect all the necessary information required at various stages

b Concentration

Concentration is the period when the designer digests all the aspects of the problem situation and tries various possible combinationsThe next step is the incubation period The designer relaxes away from the problem for some time

c Illumination

Illumination is the sudden insight and throwing up with a solution

d verification

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

The final step is the verification Now testing and inspection of the design is done and the details are completed For a designer using creative methods for design habitual or familiar methods must be avoided

ENGINEERING DESIGN (Other process)

Another procedure for obtaining innovative design is Engg Design Apart from creativity-approach this is a logical and intellectual attempt to solve design problems It largely depends on discoveries and laws of scienceThe different steps in Engg design process is given below

a Recognition of the need

Recognition of need

Definition of the problem

Gathering of Information

Conceptualization

Evaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Since all design projects are meant for satisfying some need any design work starts with Recognition of the need The need for a design is initiated by either a market requirement the development of a new technology or the desire to improve an existing product

b Define the Design problem

Once the need has identified the next step is to define the design problem This is the most critical step in the design process The definition of the problem expresses as specifically as possible what the design is intended to accomplish It should include objectives and goals definitions of any special technical terms the constraints on the design and the criteria that will be used to evaluate the designs

The success of a design project depends on the clarity in the definition of the problem Need Analysis is the technique used to define the problem

c Collecting information

The next step is collecting information In many phases of deign process a large quantity of information may be required The required information can be obtained from textbooks journals or other agencies

d Conceptualization

The conceptualization step involves finding several design ideas to meet the given need Inventiveness and creating is very important in this step

e Evaluation

The different ideas conceived are weighted and judged in the evaluation step The advantages and disadvantages of each idea against its performance cost aesthetics etc is valued

f communicating

After evaluation the best design is emerged This final design with every detail is furnished in last step-ie c ommunicating the design

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Common features between Creative Design amp Engg Design

The preparation phase in creative design and need analysis in Engg Design is more or less common Both steps deal with analyzing the need

In both design methods brainstorming and Synetics can be applied Reviewing is applicable in both design methods For both deigns the success depends on the clarity with which the need

statement is prepared Testing and inspection is applicable for both designs

Difference between Creative Designs amp Engg Designs

Intelligence is not a must for creative design-but the same is desirable in Engg Design

Creative design is based on use of analogy and synthesis of alternatives ndash but engineering design is based on proven laws and past experience

Creative design involves phases like incubation illumination ndash but no such philosophy is followed in engineering designs

Creative person is highly intuitive and independent in thinking and usually resists working in group ndash but engineering designers like teamwork

Customs habits and traditions are enemies of creativity ndash but the same are required in engineering design

TRIZ

Once the matrix has been used to find those inventive principles candidates to solve the engineering contradiction they can be applied to generate solutions for the problem at hand These inventive principles can also be used independently of the contradiction matrix as a source of ideas to solve conflicts The forty TRIZ design principles to solve engineering conflicts are Forty inventive principles

1 Principle of segmentation

Divide an object into independent parts that are easy to disassemble

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Increase the degree of segmentation as much as possibleExamples

Sectional furniture modular computer components folding wooden ruler food processor

Garden hoses can be joined together to form any length needed Drill shafts

2 Principle of removal

Remove the disturbing part or property of the object Remove the necessary part or property of the object To scare birds from buildings and airports reproduce the sound of a scare

bird using a tape recorder Hovercraft

3 Principle of local quality

Change the structure of the object or environment from homogeneous to non-homogeneous

Have deterrent parts of the object carry out different functions Place each part of the object under conditions most favorable for its

operationExamples

Fuselage skin of commercial airplanes Stapler A pencil and an eraser in one unit

4 Principle of asymmetry

Make an object asymmetrical Increase the object asymmetry

Examples

Eccentric weight on motor creates vibration

5 Principle of joining

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Merge homogeneous objects or those intended for contiguous (adjacent) operations

Combine in time homogeneous or contiguous operationsExamples

TVVCR Cassette tape heads The working element of a rotary excavator has special steam nozzles to

defrost and soften frozen ground in a single step

6 Principle of universality

Let one object perform several different functions Remove redundant objects

Examples

Sofa which converts from a sofa in the daytime to a bed at night Fingernail clipper

7 The nesting principle

Place one object inside another which in turn is placed in a third etc Let an object pass through a cavity into another

Examples

Telescoping antenna stacking chairs Mechanical pencil with lead stored inside

8 Principle of counterweight

Compensate for the weight of an object by joining it with another object that has a lifting force

Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Examples Boat with hydrofoils hot air balloon Rear wings in racing cars to increase the pressure from the car to the ground

9 Principle of preliminary counteraction

Perform a counter-action to the desired action before the desired action is performed

Examples Reinforced concrete column or oor Reinforced shaft

10 Principle of preliminary action

Perform the required action before it is needed Set up the object such that they can perform their action immediately when

required

Examples Cutter blades ready to be snapped o_ when old Correction tape

11 Principle of introducing protection in advance

Compensate for the low reliability of an object by introducing protections against accidents before the action is performed

Examples Fuses electric breakers Shaft couplers Shoplifting protection by means of magnetized plates in products

12 Principle of equipotentiality

Change the conditions such that the object does not need to be raised or lowered

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Examples Pit for change oil Loading dock airport gate

13 Principle of opposite solution

Implement the opposite action of what is specified Make a moving part fixed and the fixed part mobile Turn the object upside down

Examples Abrasively cleaning parts by vibrating the parts instead of the abrasive Lathe Mill

14 Principle of spheroidality

Switch from linear to curvilinear paths from flat to spherical surfaces etc Make use of rollers ball bearings spirals Switch from direct to rotation motion Use centrifugal force

Examples Computer mouse Screw lift

15 Principle of dynamism

Make the object or environment able to change to become optimalat any stage of work

Make the object consist of parts that can move relative to each other If the object is fixed make it movable

Examples A flashlight with flexible neck Bicycle drivetrain and derailer

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

16 Principle of partial or excessive action

If it is difficult to obtain 100 of a desired effect achieve somewhat more or less to greatly simplify the problem

Examples Raincoats snowboards

17 Principle of moving into a new dimension

Increase the degrees of freedom of the object Use a multi-layered assembly instead of a single layer Incline the object or turn it on its side Use the other side of an area

Examples A computer mouse where a 2D screen is transformed into a horizontal

mouse pad A composite wing where loads are in only one direction per layer

18 Use of mechanical vibrations

Make the object vibrate Increase the frequency of vibration Use resonance piezovibrations ultrasonic or electromagnetic vibrations

Examples Vibrating casting molds Quartz clocks

19 Principle of periodic action

Use periodic or pulsed actions change periodicity Use pauses between impulses to change the effect

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Examples Hammer drill Emergency flashing lights

20 Principle of uninterrupted useful effect

Keep all parts of the object constantly operating at full power Remove idle and intermediate motions

Examples Steam turbine mechanical watch

21 Principle of rushing through

Carry out a process or individual stages of a process at high speeds

Examples

Cutting thin wall plastic tubes at very high speeds so cutting action occurs before deformation

22 Principle of turning harm into good

Use harmful factor to obtain a positive effect Remove a harmful factor by combining it with other harmful factors Strengthen a harmful factor to the extent where it ceases to be harmful

Examples Medical defibrillator Use of high frequency current to heat the outer surface

of metals for heat treatment

23 The feedback principle

Introduce feedback If feedback already exists reverse it

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Examples Air conditioning systems Noise canceling devices

24 The go between principles

Use an intermediary object to transfer or transmit the action Merge the object temporarily with another object that can be easily taken

away

Examples Gear trains

25 The self-service principle

The object should service and repair itself Use waste products from the object to produce the desired actions

Examples

Nail resistant tires

26 The copying principle

Instead of unavailable complicated or fragile objects use a simplified cheap copy

Replace an object by its optical copy make use of scale effects If visible copies are used switch to infrared or ultraviolet copies

Examples Rapid prototyping Crash test dummies Measure shadows instead of actual objects

27 Cheap short life instead of expensive longevity

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Replace an expensive object that has long life with many cheap objects having shorter life

Examples Inkjet printer heads embedded in ink cartridges Cardboard box

28 Replacement of a mechanical pattern

Replace a mechanical pattern by an optical acoustical or odor pattern Use electrical magnetic or electromagnetic fields to interact with the object Switch from fixed to movable fields changing over time Go from unstructured to structured fields

Examples CD player Microwave oven Crane with electromagnetic plate

29 Use of pneumatic or hydraulic solutions

Replace solid parts or an object by gas or liquid

Examples Power steering Bubble envelopes

30 Using flexible membranes and fine membranes

Replace customary constructions with flexible membranes and thin film Isolate an object from outside environment with thin film or fine

membranes

Examples Dome tent High Altitude Balloon

31 Using porous materials Make the object porous or use porous elements

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

If the object is already porous all the pores in advance with some useful substance

Examples Running shoe soles Air filters

32 The principle of using color Change the color or translucency of an object or its surroundings Use colored additives to observe certain objects or processes If such additives are already used employ luminescence traces

Examples Transparent bandage Roadway signs

33 The principle of homogeneity

Interacting objects should be made of the same material or material with identical properties

Examples Shaft and bushing

34 The principle of discarding and regenerating parts Once a part has ful_lled its purpose and is no longer necessary it should

automatically be discarded or disappear Parts that become useful after a while should be automatically generated

Examples Multistage rockets Bullet castings

35 Changing the aggregate state of an object Change the aggregate state of an object concentration or density the degree

of flexibility or its temperature

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Examples Heat packs Light sticks

36 The use of phase changes Use phenomena occurring in phase changes like change of volume and

liberation or absorption of heatExamples

Fire extinguisher

37 Application of thermal expansion Use expansion or contraction of materials by heat use materials with different thermal expansion coefficients

Examples Thermometers Bimetallic plates

38 Using strong oxidation agents Replace air with enriched air or replace enriched air with oxygen Treat the air or oxygen with ionizing radiation Use ionized oxygen or ozone

Examples Metal forming ovens Torch cutting

39 Using an inert atmosphere Replace the normal environment with an inert one Carry out the process in a vacuum

Examples Aluminum cans for beverages Arc welding

40 Using composite materials

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Replace a homogeneous material with a composite one

Examples Steel belted tires Tennis racquets High performance aircraft wings

Divergence Transformation amp Convergence

The entire design process can be said to have composed of three distinct phases Viz Divergence Transformation and Convergence phases

The problem definition need analysis and conceptualization etc aims at generating as many ideas as possible to solve a given design problem Thus these activities belong to the Divergence phase

That activity wherein the concept is converted into physical object is termed as transformation phase The convergence is a narrowing process where the best optimal solution is tried for by eliminating unwanted ideas

Design Process Using Advanced Technology

Although Engineering is a major sector of the economy in a developing country It has not been benefited greatly from advances in computer technology Engineers still use computers only in peripheral tasks such as drafting and analyzing but not in making fundamental design decisions Current computer tools such as lsquocomputer-aided drafting are restricted to the end of the design process and play no fundamental role in aiding design It aids only in the final drafting of the specifications Computer-aided Design (CAD) means a class of tools for crating drawing or the physical description of the object CAD systems have been sophisticated and 2D and 3D models are available

The CAD allows the designer to conceptualize objects more easily The design process in CAD system consists of the following stages

o Geometric modeling

o Analysis and optimization

o Evaluation

o Documentation and drafting

DESIGN FOR ASSEMBLY

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Why Design for AssemblyDesign for Assembly is an exercise to facilitate ease of assembly when manufacturing a component with multiple parts Obviously the reduction in the total number of parts for an assembly has the added benefit of reducing the total cost of parts in the assembly Design for Assembly should ideally be considered at various stages during the selection of material shape and processes so that the overall manufacturability and assembly of the component are facilitatedAssembly Processes and GuidelinesThe assembly processes involve the proper placement and appropriate integration of more than one parts to manufacture a final component The assembly processes can be broadly classified into three classes Adhesives Fasteners and Welding These classes can be further divided into several sub-classes

UNIT II

Quality Function Deployment

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

bull QFD is a planning and problem-solving tool that is finding growing acceptance for translating customer requirements into the engineering characteristics of a product

bull Group decision-making activitybull Graphical representatin using a diagram called ldquoHouse of Qualityrdquo

1Customer Requirements

Affinity diagram

Used organize the ideas facts opinions

2Competitive assessment

Competitive product rank wrto two or three products scale 1-5

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

3Important ratings

Product of customer importance improvement ratio and sales point

Relative weight

Each value of importance weight divided by sum of all values of importance weight

Sum of relative weight is equal to unity

4 Engineering characteristics

Satisfying the customer requirements are listed in column

Characteristics that can be measure and given target value weight force velocity and etc

+ indicates higher value is better

- Lower value is better

5The correlation matrix

The degree of interdependence among the engineering characteristics in the ldquoroof of house

9 or a strong relationship

3 or O medium relationship

6Relationship matrix

ndash the correlation between the engineering characteristics and customer requirements

ndash Non linear scale 9310 weight disproposonality those ECs strongly effect customer requirements

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

7Absolute importance

ndash multiply the numerical value in each of the cells of the relationship matrix[6] by the importance rating [3] then sum of the numbers in the cells each column

8Relative importance

normalized scale 1 to 100 each value absolute importance divide by total and multiply by 100

9Technical competitive assessment bench mark scale1 to 5

10Technical Difficulty Ease with which each of the ease ECs can be achived

1- low probability success

5- high probability of success

11Target value satisfy the requirements

ndash By knowing important ECs technical competition feel for the technical difficulty team to said target value for each ECs

From customer requirement to production planning

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Product Design Specification (PDS)

The basic control and reference documents for the design and manufacture of the product

The PDS is a documents which contains all of the facts related to the outcome of the product development

Elements

performance

speed

capacity

power

accuracy

bull In-use purpose amp marketndash Product titlendash Function the product is to performndash Special features of the productndash What is the intended marketndash Relationship of the product to the other company productsndash Target company selling price and estimated retail price

bull Functional requirementsndash Functional performance flow of energy information

materials operational steps accuracy efficiencybull Physical requirements

ndash Size weightshapesurface finishndash Service requirementndash Factory floor transportation humidity dirt

bull Life ndashcycle issues human factorsndash Useful life aestheticsndash Reliability man-mc interface

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

ndash Robustness user trainingndash Maintainabilityndash Testabilityndash Repairabilityndash Installabilityndash Retirement from service and recyclabilityndash Cost of operation

bull Corporative constraintsndash Time to marketndash Manufacturing requirementndash Suppliersndash Financial performancendash Corporate ethics

bull Social political legal requirementsndash Safety and environmental regulationsndash Standardsndash Product liabilityndash Patents and intellectual property

ndash Complete possible outset of designndash Quantitative

ERGONOMIC NEEDS

Planning the workflow to eliminate unnecessary lifting lowering and carrying of materials

Organizing work so that physical demands and work pace increase gradually

Minimizing distances materials are lifted lowered and carried

Reduce the frequency of lifting lowering and carrying and the amount of time spent in these tasks by rotating workers through tasks

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Clear spaces to improve access to materials being handled which allows workers to get closer and reduces reaching bending and twisting

PROCESS OF IDENTIFYING CUSTOMER REQUIREMENTS

bull Define the Scopendash Mission Statement

bull Gather Raw Datandash Interviewsndash Focus Groupsndash Observation

bull Interpret Raw Datandash Need Statements

bull Organize the Needsndash Hierarchy

bull Establish Importancendash Surveysndash Quantified Needs

bull Reflect on the Processndash Continuous Improvement

Example Screwdriver Project

Product Description

bull A hand-held power-assisted device for installing threaded fastenersKey Business Goals

bull Product introduced in 4th Q of 2000bull 50 gross marginbull 10 share of cordless screwdriver market by 2004

Primary Market

bull Do-it-yourself consumerSecondary Markets

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

bull Casual consumerbull Light-duty professional

Assumptions

bull Hand-heldbull Power assistedbull Nickel-metal-hydride rechargeable battery technology

Stakeholders

bull Userbull Retailerbull Sales forcebull Service centerbull Productionbull Legal department

The process

1 Gather raw data from customers2 Interpret raw data in terms of customer needs3 Organize needs into a hierarchy (primary secondary etc)4 Establish relative importance of each need5 Reflect on the results and the process

2 Gather raw data from customers1 Interviews2 Focus groups3 Observing product in use

3 Interpret raw data in terms of customer needs1 Express need as ldquowhatrdquo not ldquohowrdquo2 Express the need as specifically as the raw data3 Use positive not negative phrasing4 Express the need as an attribute to the product5 Avoid the words must and should

3 Organize needs into a hierarchy(one method)

bull Print each need on separate cardpost-it

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

bull Eliminate redundant statementsbull Group cards according to similar needs metbull Choose a label for each groupbull Create supergroups (2 to 5 groups) where possiblebull Review edit the organized need statements

4 Establish relative importance of each needbull Develop a weighting system for customer needs

ndash Rely on consensus of the team based on their experience with customers

Or

ndash Use further customer surveys5 Reflect on the results and the process

bull Are results consistent with results of teamrsquos interaction with the customers

bull Have all important types of customers in target market been interacted with

bull What do we know that we didnrsquot know when we started Any surprises

bull How can we improve the processPROCEDURE TO SOLVE ETHICAL CONFLICTS

1 DETERMINE whether there is an ethical issue orand dilemma Is there a conflict of values or rights or professional responsibilities (For example there may be an issue of self-determination of an adolescent versus the well-being of the family)

2 IDENTIFY the key values and principles involved What meanings and limitations are typically attached to these competing values (For example rarely is confidential information held in absolute secrecy however typically decisions about access by third parties to sensitive content should be contracted with clients)

3 RANK the values or ethical principles which - in your professional judgement - are most relevant to the issue or dilemmaWhat reasons can you provide for prioritizing one competing valueprinciple over another (For example

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

your clients right to choose a beneficial course of action could bring hardship or harm to others who would be affected)

4 DEVELOP an action plan that is consistent with the ethical priorities that have been determined as central to the dilemmaHave you conferred with clients and colleagues as appropriate about the potential risks and consequences of alternative courses of action Can you support or justify your action plan with the valuesprinciples on which the plan is based (For example have you conferred with all the necessary persons regarding the ethical dimensions of planning for a battered wifes quest to secure secret shelter and the implications for her teen-aged children)

5 IMPLEMENT your plan utilizing the most appropriate practice skills and competencies How will you make use of core social work skills such as sensitive communication skillful negotiation and cultural competence (For example skillful colleague or supervisory communication and negotiation may enable an impaired colleague to see herhis impact on clients and to take appropriate action)

6 REFLECT on the outcome of this ethical decision making process How would you evaluate the consequences of this process for those involved Client(s) professional(s) and agency (ies) (Increasingly professionals have begun to seek support further professional training and consultation through the development of Ethics review Committees or Ethics Consultation processes)

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Instructional objectives

The primary objective of this lecture module is to outline how to identify the need and define the problem so as to begin with the activities and steps involved in design for manufacturing processSteps involved in Engineering Design processFigure 111 schematically outlines the typical steps involved in an engineering design process

Fig Discrete steps involved in engineering design process It also mentions the important techniques used in each stepsConceptual design

It is a process in which we initiate the design and come up with a number of design concepts and then narrow down to the single best concept This involved the

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

following steps

1 Identification of customer needs The mail objective of this is to completely understand the customersrsquo needs and to communicate them to the design team

2 Problem definition The mail goal of this activity is to create a statement that describes what all needs to be accomplished to meet the needs of the customersrsquo requirements

3 Gathering Information In this step we collect all the information that can be helpful for developing and translating the customersrsquo needs into engineering design

4 Conceptualization In this step broad sets of concepts are generated that can potentially satisfy the problem statement

5 Concept selection The main objective of this step is to evaluate the various design concepts modifying and evolving into a single preferred concept

Embodiment design

It is a process where the structured development of the design concepts takes place It is in this phase that decisions are made on strength material selection size shape and spatial compatibility Embodiment design is concerned with three major tasks ndash product architecture configuration design and parametric design

1 Product architecture It is concerned with dividing the overall design system into small subsystems and modules It is in this step we decide how the physical components of the design are to be arranged in order to combine them to carry out the functional duties of the design

2 Configuration design In this process we determine what all features are required in the various parts components and how these features are to be arranged in space relative to each other

Parametric design It starts with information from the configuration design process and aims to establish the exact dimensions and tolerances of the product Also final decisions on the material and manufacturing processes are done if it has not been fixed in the previous process One of the important aspects of parametric designs is to examine if the design is robust or not

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

Detail design

It is in this phase the design is brought to a state where it has the complete engineering description of a tested and a producible product Any missing information about the arrangement form material manufacturing process dimensions tolerances etc of each part is added and detailed engineering drawing suitable for manufacturing are prepared

Need identification amp Problem Definition

Out of all the steps in the engineering design process the definition of the problem is by far the most important step A complete and thorough understanding the problem is prerequisite in achieving the targeted solution For example the ultimate test of a product is how well it sells However it is first essential to understand and provide what a customer wants in the product which can only be achieved by defining the problem precisely at the first place

a Prior activities

In majority of the situations a significant amount of development work precedes the tight definition of a design problem These a-priori development works can generally be referred to planning The primary purpose of the planning stages is to collect all the necessary information and to decide for example whether manufacturing a new product is feasible or what would be the best time to market a new or modified product or whether a specific company has the adequate resource to manufacture a new product Usually the initial design projects can be categorized as follows

Variation of existing productThis includes minor changes in few parameters of an existing the product eg change in the power of a motor or change in the design of a typical clamping bracket and so onImprovement in an existing productThis involves major redesign of an existing product primarily to improve performance and quality update features (may be due to competitions) reduce cost in manufacturing and so onDevelopment of a new product for a low-volume production run

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

This is primarily referred to new parts or products that would possibly be manufactured in smaller number of units (eg lt 10000) In many cases a large manufacturing unit may wish to buy standard available components available from smaller manufacturing units rather than actually making the same to avoid additional costsDevelopment of a new product for mass productionThese include products or parts which need to be produced in large volumes eg in the category of automobiles home appliance etc Such design projects provide the design engineer the flexibility in selecting appropriate material and manufacturing process through careful planningOne-of-a-kind designSuch projects can vary from a simple quick design requiring minimum of analysis like designing of a welding fixture to hold parts to large exclusive projects such as building of a 200-MW steam turbine

Product life cycle

Every product goes through a cycle from birth followed by an initial growth stage a relatively stable matured period and finally into a declining stage that eventually ends in the death of the product as shown schematically in Figure

1 Introduction stage In this stage the product is new and the customer acceptance is low and hence the sales are low

2 Growth stage Knowledge of the product and its capabilities reaches to a growing number of customers

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle

3 Maturity stage The product is widely acceptable and sales are now stable and it grows with the same rate as the economy as a whole grows

4 Decline stage At some point of time the product enters the decline stage Its sales start decreasing because of a new and a better product has entered the market to fulfill the same customer requirements

Figure Schematic outline of a product life cycle