process introduction. types of processes. process strategy in the industry. factors affecting...

Process

Introduction.

Types of Processes.

Process Strategy in the industry.

Factors affecting Process Design.

Tools

Process Introduction Classification of Processes Process strategies at the Industry Factors that affect (or are affected by) the Process

Selection. Tools

SPC, SMED… Documents Work Measurement and Standards Job Place Design Line Balancing Measuring Process Performance Queueing Theory

Introduction The information generated during the product design phase specifies

how the product must be, but not how to organize the production process to make it (equipment, labor skills required, etc.).

Process Design specifies how the activities that Operations must carry out should be developed: Guiding the election and selection of technologies. Clarifying the quantity and type of resources to be acquired, when to be

acquire and their availability. Process design and redesign is intimately related to Product Design:

Concurrent or Simultaneous Engineering.

Process Selection and System Design

Forecasting

Product andService Design

TechnologicalChange

CapacityPlanning

ProcessSelection

Facilities andEquipment

Layout

WorkDesign


Selection. Tools


The process-focused Project ShopCharacteristics1. “Unique” products with certain complexity (boats, aircrafts, trains, motorways…)2. The production process is managed like a project3. Makes a one-of-a-kind product (volume = 1)4. Uses general purpose equipment5. Has informal relationships with many vendors6. Very little vertical integration7. Flexible layout often with factors of production moving to job

The Job ShopA process structure suited for low volume production of a great variety of non-standard

products (highly customized products).Custom or workshop: Low specialized operations carried out by the same worker or group

of workers that follow up the whole process for the order.Batch: More specialized operations carried out by different workers or group of

workers (need for more specialization and standardization).

Characteristics1. Makes many products in small volume 2. Uses general purpose equipment, grouped by the same function in Work Centres3. Has informal relationships with vendors4. Very little vertical integration5. Departmentalized layout with chaotic flow

The Large Batch (Cell, Flow Shop or Hybrid Shop)A process structure that produces a variety of standard products at relatively low volumes. This variety of standard products has a similar sequence of operations:

The equipment is laid out in line, instead of grouped by the same function.After completing one batch, equipment adjustments for the next one are made and the next batch produced.

Characteristics1.Makes several families of products in moderate volume 2.Uses general purpose equipment often customized3.Little vertical integration4.Similar product follows the same path, produced in batches to reduce the impact of setup time.5.Hybrid layout with flow lines

A process structure designed to make discrete parts. Parts are moved through a set of specially designed workstations at a controlled rate.

Characteristics

1.Makes few products in large volume 2.Uses specialized high-volume equipment 3.Has formal relationships with vendors4.May use vertical integration5.Product-based layout with linear flow

Assembly Line

Continuous FlowAn often automated structure that converts raw

materials into finished products in one continuous process. Same operations are made in the same equipment to make

the same product, reducing waiting time. Objectives:

Improvement of material flow and operations. Workers specialization:

Increasing speed and added value.

Types of Processes Flexibility and Costs

By Projects Job Shop Flow Shop Assembly Line Continuous

FlexibilityFixed CostVariable Cost

Unit Cost

+

- +

-


Selection. Tools


Process Strategy in the industry Manufacturing Process Life Cycle

Processes go through different phases as products do.

Interdependency between Product and Process Life Cycles: Process Life Cycle: Affects manufacturing costs,

quality and production volumes, which affects sales volumes.

Product Life Cycle: Influences the type of manufacturing process that can be economically and financially justified.

Process Strategy in the industry Product-Process Matrix

IV.Continuous

Flow

III.Assembly

Line

II.Batch

I.Job

Shop

LowVolume,One of a

Kind

MultipleProducts,

LowVolume

FewMajor

Products,HigherVolume

HighVolume,

HighStandard-

ization

CommercialPrinter

French Restaurant

HeavyEquipment

AutomobileAssembly

Burger KingSugar

Refinery

Flexibility (High)Unit Cost (High)

Flexibility (Low)Unit Cost (Low)

These are the major stages of product and process life cycles

These are the major stages of product and process life cycles

Process Strategy in the industry The Product-Process matrix and the Competitive Advantage

The Product-Process matrix helps companies define where their competencies are, concentrating their attention in a limited group of decisions and process alternatives, as well as a limited group of Marketing options.

When the company considers at the same time products and processes, it can increase its probability of success.

Place in the matrix and Competitive priorities Organization of the Operations and the Product-Process

matrix

Process Strategy in the industry The Product-Process matrix and the Competitive Advantage Place in the matrix and Competitive priorities

Operations Management priorities change as the Product-Process combinations change. I.e.- Flexibility vs. Standardization

Each company has to take into account its traditional focus when positioning in the matrix: Market oriented: Flexibility and Quality. Manufacturing oriented: Costs and Process Leadership.

Organization of the Operations and the Product-Process matrix

Process Strategy in the industry The Product-Process matrix and the Competitive Advantage Place in the matrix and Competitive priorities Organization of the Operations and the Product-Process matrix

Paying attention to the process that makes the company more competitive, the company will be able to manage the development of the operations involved per line of products.

The knowledge about how the different positions in the matrix affect manufacturing will lead the company to suggest changes in Operations Management.

Companies that compete with several products in different markets will probably have their products in different stages of the life cycle: Companies should separate and organize their processes in different

areas focalized in the different life cycles.


Selection. Tools


Process Selection and System Design

Forecasting

Product andService Design

TechnologicalChange

CapacityPlanning

ProcessSelection

Facilities andEquipment

Layout

WorkDesign

Factors affecting Process Design Capital Investment Flexibility Vertical Integration / Outsourcing Nature of Demand Quality of the product or service Customer participation The Learning effect Financial Planning and Evaluation

Factors affecting Process Design Capital Investment

Combination of equipment and human resources at the manufacturing process.

The new manufacturing technologies provide a wide variety of available options: As the mechanical and/or automated operations

increase, more capital is required. Most of the available options require a high capital

investment, which create a high risk in case our sales volumes (and therefore our production volumes) are lower than the expected.

Factors affecting Process Design Flexibility

A production process is more flexible when their equipment and human resources are able to manage a wider variety of products, outputs, responsibilities and functions, at a reasonable cost and time frame.

Capital vs. FlexibilityFlexibility

Capital

Traditional technologies

New technologies

Factors affecting Process Design Flexibility

Flexibility affects the type of human resources required and their job stability: More training is required. Job stability is more variable for companies working by

projects or job shop type of process. Flexibility is one of the best ways to get a reliable

customer service and reduces bottle necks.

Factors affecting Process Design Vertical Integration/Outsourcing

The degree of vertical integration is related to the number of processes at the supply chain that are carried out by the own company.

The vertical integration can generate savings when the company has the necessary skills to carry out some processes at a lower cost and better quality.

If the resources acquired are basic, the company may loose competitiveness with non-vertical integration.

Outsourcing is interesting when a resource consumption is low, and its efficient management has a certain economy of scale.

Outsourcing is used as well when the technology to be used is so complex that being competitive requires a big effort not balanced with the benefits obtained.

Factors affecting Process Design Nature of the demand

Manufacturing processes have to have the necessary capacity to support the demand of products and services that the company is going to offer.

Seasonality, tendency and other characteristics of the demand are going to affect the capacity required over the time. Some processes are able to expand and contract more easily than others. The final selection of processes will be affected by the estimated demand.

Price: If it’s high, consumers will tend to buy less and vice versa. To fix the price, the company has to take into account factors like

advertising costs, sales force, financial conditions, services provided to the customer, specific designs, inventory and delivery policy, quality, etc., at the same time than the costs related to manufacturing.

It should be coordination between product price and process selection, due to the competitive advantages provided by the different types of processes

Factors affecting Process Design Quality of the product or service

Quality is a competitive advantage in the current business environment. The level of quality to be offered will affect directly the selection of the

production process. The level required is directly related to the level of automation of the

process, since the automatic equipment manufactures products with a high and consistent uniformity.

Customer participation Services that require higher contact with the customer generally

need less capital investment and have more flexibility. Customer presence normally affects the process efficiency in a

negative way, which increases cost.

Factors affecting Process Design The Learning effect

The working hours required per unit of product represent a decreasing function of the number of cumulative production units.

This reduction of working hours (and therefore cost) are based on the gain of experience in design of products and services, automation and capital investment, as well as changes in methods and experience of the working force.

Companies competing in price try to have high manufacturing volumes to take advantage of the learning effect, and therefore have a lower cost.

Production volumeW

orki

ng

hour

s pe

r un

it

Factors affecting Process Design Financial Planning and Evaluation

Operation managers are continuously looking for new and different ways of producing that: Increase productivity. Follow the Operations Strategy. Provide sufficient profit to justify the capital investment

required. Each type of process has different capital

requirements, thus limiting the company’s possibilities of process selection in case of limited financial resources.


Selection. Tools


Tools and Concepts

Simplify/Mechanize/Automate/Integrate SMED CAD/CAM Statistical Process Control Bottlenecks

How much is the profit?A company manufactures 2 products P & Q. Sale price of P is 90 € and Q price is 100 €/unit. Weekly Demand is 100 units for P and 50 units for Q.Both products require the same PC component, the raw material of which worths 20 €/unit. To transform PC 15 minutes of a given resource B are required and 5 minutes of a given resource C.Product P also requires Component 1 (C1) that should be transformed from a raw material that cost 20 €/unit, and it requires 15 minutes of a given resource A and 10 minutes of C.To assembly PC with C1 a new component C3 is required with a cost of 5 €/unit and 5 minutes of the D resource.Product Q follows a very similar process. To manufacture C2 raw material with a cost of 20 €/unit is needed, and it is processed using 20 minutes of A and 15 minutes of B. Then resource D assembles PC with C2 during 5 minutes.Each week has 5 days of 4 hours. Total cost are 3600 €/week.


Selection. Tools


Work Measurement and Standards

The Purpose of Work Measurement is to set time standards for a job. Such standards are necessary for 4 reasons: To schedule work and allocate capacity. To provide an objective basis for motivating the workforce. To bid for new contracts and to evaluate performance on existing ones. To provide benchmarks for improvement.

Methods Time Study (stop watch) Work Sampling (observing a sample) Predetermined times Elementary standard data Reference points.

Reference Book (B.W. Niebel, Motion and Time Study)

Time Study A time study is generally made with a stopwatch, either on the spot

or by analyzing a videotape for the job. The job or task to be studied is separated into measurable parts

and then timed individually. Some general rules

Define each work element to be short in duration but long enough to be timed and the time can be written

Separate activities related with machine from the rest. Define any delays or acyclic activities. After a number of repetitions, collection times are averaged.

Normal Time = Observed Performance Time x Performance Rating Standard Time = NT x (1 + Allowances)

Work Sampling Three primary applications

Determine the activity-time percentage for personnel or equipment.

Performance measurement to develop a performance index for workers.

Evaluate time standards to obtain the standard time for a task. Five Steps

Identify the specific activities that are the main purpose for the study.

Estimate the proportion of time of activity of interest of the total time.

State the desired accuracy in the study results. Determine the specific times when each observation is to be

made. At two or three intervals during the study period recompute the

required sample size by using the data collected thus far.

Get Put

Move with Weight (5 UMT)

Grasp (6 UMT)

Bend Down (29 UMT)

Stand up (32 UMT)

Apply Presure (14 UMT)

Eye Movement (7 UMT)

Step (18 UMT)

Coger funda GDF 25Coger "tinta" GDF 25

Poner "tinta en funda" PDN 19Coger y Poner GEN+PEN 5+8

Aplicar Presión 14Coger caperuzón GDF 25

Reajustar tras coger 6Poner caperuzón PDN 19

Aplicar Presión 14Dejar bolígrafo PEF 14

6.3 seconds

N X F

PE 5 9 14

PD 19 22 28

N X F

GE 8 13 16

GD 17 20 25

Predetermined Motion Times (MTM, MODAPTS, )


Selection. Tools


Documents Flowchart.A flowchart is a graphical

representation of a process, depicting inputs, outputs and units of activity. It represents the entire process at a high or detailed (depending on your use) level of observation, allowing analysis and optimization of workflow.It can serve as an instruction manual.

Assembly Drawing: An exploded drawing containing a set of number parts combined to make a complet product.

Value Stream Map: Value stream mapping is a paper and pencil tool that helps you to see and understand the flow of material and information as a product or service makes its way through the value stream.

Operation

Begin or end

Informationinput

Informationoutput

Shampoo directions1. Lather2. Rinse3. Repeat

Process Documentation using Flowcharts

Basic flowchart symbols

Example: Any problems with the following set of directions?

Questionyes/no?

Shampoo?

Begin shampoo

Rinse hair with warm water

Lather shampoointo hair

Select bottle

Wet hair withwarm water

Informationon bottle

No

Yes

Hairclean?

NoEnd shampoo

Yes

Process Flow Diagram (PFD)A process flow diagram is a mapping of the specific processes that raw materials,parts, and subassemblies follow as they move through a plant.

Builds on the concept of flowcharting.Activity

A more constrained version of the operation symbol used in flowcharting1. Requires a resource2. Resource has a capacity constrain3. Adds value

Flow1. Arrow indicates the flow of jobs2. Multiple flow units (types of jobs) possible

Buffer

Buffer or inventory location1. Normally does not have a capacity2. Multiple units possible

TreesRM

Debark StemsWIP

Scan SawAcceptable

LumberFG

Grind ChipsFG

Acceptable

Flow Diagrams

Single Object Process Chart

Assembly Process Chart Assembly charts

Disassembly charts

Action Decision Flow Diagram

Multi Activity Charts


Selection. Tools


Job Design (I) Job design is the function of specifying the work activities of an

indidividual or a group in an organizational setting. The objective is to develop job structures that meet the

requirements of the organization and its technology and that satisfy the job holder’s personal and individual requirements.

Trends of Job Design Decisions Quality control as part of the workers job Cross training workers to perform multiskilled jobs Employee involvement and team approaches to designing and

organizing work “Informating” ordinary workers through internet, email… Extensive use of temporary workers Automation of heavy manual work Organizational commitment to providing meaningful and rewarding

jobs for all employees.

Job Design (II) The improvement of the job methods leads to a higher level of specialization.

A workplace with a high level of specialization covers a narrow set of tasks, high repetitive levels, and, hopefully, high efficiency and quality.

Specialization produce benefits as quicker training and faster working rates. This way of working has also some disadvantages as worker demoralization,

reduces flexibility and increases the work of upper levels of management.

To avoid those disadvantages: Wider jobs

Job enlargement (horizontally expanded) Job enrichment (vertically expanded)

Job Rotation Socio-Technical Systems

Task variety Skill variety Feedback Task identity Task autonomy


Selection. Tools


Line Balancing Introduction Line Balancing

Mathematical Programming Model Heuristic Methods Yamazumi

Duration of the Tasks Longer than Cycle Time Other Considerations.Other Considerations. Mixed Model Assembly LineMixed Model Assembly Line

Introduction The design of the line, constraints the alternatives when

scheduling the activity of the line.

A decision on the productive system (in the long term):

Defines the allocation of facilities.

Constrains the sequence (lines with mixed models).

Constrains the production volumes (lines multi-model).

Assembly line

Manufacturing

Made and bought inventory of components and subassemblies

Conveyor moving at constant speed

WorkStation 1

WorkStation 2

WorkStation m

Final product

inventory

1 2 3 4 NIn Out

1 2 3 4 NIn Out

1 2 3 4 NIn Out

single model line

batch model line

mixed model line

Production Organization

Use of the Assembly line Advantages

Performance increase due to the learning effect. Reduces the difficulty of the task. Increases the team work, avoiding isolations. Constant rate of work. Ongoing quality control.

Disadvantages Alienation. Less flexibility.

Line Balancing. Definition.

Line Balancing consists of assigning operations to the workstations of such form that the sum of their durations in each station is as similar as possible.

With this procedure bottlenecks should be avoided, unproductive time will be reduced and the productivity of the line will increase.

This implies that: Each operation will be assigned to an one only

and only one workstation. Relations and bounds between operations will be

respected. Times of the stations will not exceed their cycle

time.

Objectives. Capacity

Minimization of total idle time (maximization of the use of the line).

Minimization of product flow-time. Balance the levels of capacity used at the workstations.

Cost Minimization of the machinery costs, tools or idle equipment. Minimization of the costs of materials or reworks. Minimization of the costs by adjustment and change.

Organizational-social Job Enrichment Modifications at the Line balancing

General definitions.(I) Operation: Smaller unit of work than cannot be divided without creating an

unnecessary interference. Workstation: Segment of the line where a set of operations is executed.

Characterized by its surface, machinery or type of assigned work. Line Balancing: Process to assign operations to workstations. It intends to assign

personal or equipment of efficient way to obtain the performance maximum. Cycle time: Amount of time between two consecutive products.

Balance Efficiency: It indeed represents the percentage of invested total time in making products.

Station Pitch: The distance of a product and the one that follows to him in the conveyor belt.

ProductionForecast

Time Avalaible Time Cycle

Stations Nº x Cycle Time Operations Total Time Efficiency

General Definitions. (II) Bounds between operations.

Precedence Relations. Imposed generally by technological constraints. “Operation 'í' cannot be made if before the 'h' has not

taken place” In the case of linear configurations, this implicates

that 'h' will have to be in the same station that 'i' or in a previous one, but never in a following one.

General Definitions. (III) Positive ZoningPositive Zoning.

It is compulsory to locate an operation in the same station that another one.

Operations that need the same tool Operations that need the same ability on the part of the

worker Operations that need the same physical training conditions

Negative Zoning or incompatibility.Negative Zoning or incompatibility. It is demanded that an operation is not in

the same station that another one. Position of the unit in the line (Operations to be made at the

right side

are not compatible with those to be made at the left)

Exigency of a high specialized workers

Processes of painted sandpapering and of surfaces

Allocation of varied activities to avoid monotony.

Limit Zone.Limit Zone. It is demanded that certain operations are

assigned to stations previous or next to one given

Fixed zone of material arrival.

Zone of preparation or control.

General Definitions. (IV)

jiij tTO m1,...,=j;

Line Speed

Productivity

Operation Time in a station

Minimum number of workstations

LV=L/C

CP

1

C

tN

n

ii

ws

1

1 minute

TOTO 1 minute

C C

General Definitions. (IV) Idle time of a station

Total idle time of a station or delay

Station saturation

Efficiency

Delay

n

ii

m

jj tCmTOCD

11

)(

...

0.9 minutes

1 minute1 minute

m1,...,=j;ij TOCDI

m1,...,=j;C

TOS ij

100(%) 1

Cm

tE

n

ii

(%)100(%) ER


Mathematical Programming Model Heuristic Methods


Resolution Procedures for problem SALBP 1.

Exact methods Mathematical Programming Models Exact algorithms of directed exploration and dynamic

programming.

Heuristic methods Constructive. Based on rules and strategies

Heuristic of a single one happened. Simple Composed Heuristic with backward movement

Approaches from exact algorithms Others

Model of PLM of problem SALBP1.

Variables of allocation xij: Binary variables that they indicate if operation i is assigned to station j.

Variables of existence yj: Binary variables that they indicate if station j exists. This existence comes imposed when not being able to assign but operations to anyone of the stations already defined.

mmax

jjyzMIN

1

sujeto a:

mmax

jjix

1, 1 i=1…n [1]

n

ijjii yCxt

1, j=1…mmax [2]

mmax

j

mmax

jjpji xjxj

1 1,, i precede a p [3]

ij yy 1 j=1…mmax-1 [4]

jix ji ,1,0,

jy j 1,0

Heuristic procedures Although nonexact, some heuristic

procedures provide solutions that can be considered acceptable.

The known procedures of constructive type more are the bound ones to the duration of the task or the number of consequent.

One of them chooses to assign to the open station the task with greater duration than still it fits in the station.

The alternative procedure chooses to assign to the open station the task with greater number of consequent.

Yamazumi

1

2 3

45 6

7

8

9

10

11

12

CYCLE TI

Me

Objectives. Capacity

Minimization of total the idle time (maximization of the use of the line).

Minimization of products flow-time in the line. Balance the levels of capacity use at the workstations.

Cost Minimization of the machinery costs, tools or idle equipment. Minimization of the costs of materials or reworks. Minimization of the costs by adjustment and change.

Organizational-social Job Enrichment Modifications in the Line balancing


Mathematical Programming Model Heuristic Methods Yamazumi


Operation Time Preceding Task Operation Time Preceding Task1 0,175 - 16 0,200 -2 0,139 - 17 0,084 -3 0,078 1 18 0,116 13;154 0,349 - 19 0,199 185 0,007 - 20 0,079 196 0,050 - 21 0,103 197 0,211 4 22 0,098 98 0,158 - 23 0,116 199 0,230 8 24 0,210 2310 0,080 9 25 0,140 2411 0,075 - 26 0,210 2512 0,395 9 27 0,177 2613 0,219 12 28 0,234 2714 0,188 - 29 0,090 -15 0,122 12

A real Example

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78

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1510

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Yamazumi Graphics Example

1

2

3

4

56

78

17

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2122 23

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28 29

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9

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Yamazumi Graphics Example


Selection. Tools


Measuring Process Performance Productivity: Ratio of Output to Input Effiency: Ratio of Actual output to some standard. Utilization: Ratio of the time that a resource is actually activated

relative to the time that it is available for use. Cycle time (takt time): Average time between the completion of

succesive units. Run Time: time required to produce a batch of parts Setup Time: is the time required to prepare a machine to make a

particular item. Operation Time: sum of setup and run time. Throughput time: time that unit spents actually being transformed

or waiting. Throughput rate: output rate that the process is expected to

produce over a period of time. Process velocity: Total throughput divided by Value Added Time Value Added Time: Time that useful work is actually done


Selection. Tools


Queueing Theory Little’s Law: The size of a queue is proportional to the input

rate and the average throughput time.

L= WLq = Wq

1 qWW

process introduction. types of processes. process strategy in the industry. factors affecting...

Documents

process design

production process

process structure

process strategy

job slide

product design phase

tools slide

customized products