chapter a - intro
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PURPOSE:PURPOSE:
By the end of this semester, you will:By the end of this semester, you will:
have identified and understand thehave identified and understand theelements in CAD and CAM inelements in CAD and CAM in
designing process.designing process.
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SYLLABUSSYLLABUSA.A. Introduction of CAD (T & P)Introduction of CAD (T & P)
B.B. Control System (T)Control System (T)
C.C. Part programming (T & P)Part programming (T & P)D.D. Interfacing (T)Interfacing (T)
E.E. CADCAM Integration (T)CADCAM Integration (T)
F.F. Concept of Manufacturing (T)Concept of Manufacturing (T)
NoteNote::
T T ±± Theory & P Theory & P ±± Practical (CADCAM SoftwarePractical (CADCAM Software ±± EdgeCAMEdgeCAM))
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ASSESSMENT SCHEME (100%)ASSESSMENT SCHEME (100%)
AssignmentAssignment -- 20 %20 %QuizQuiz -- 20 %20 %
Practical (drawing & project)Practical (drawing & project) -- 20 %20 %
TestTest (drawing & theory)(drawing & theory) -- 40 %40 %
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Chapter 1Chapter 1
A.A. INRODUCTION OF CADINRODUCTION OF CAD
Definition:Definition:
Computer Computer--aided design (CAD) can beaided design (CAD) can bedefined asdefined as any design activity that involvesany design activity that involves
the effective use of the computer to create,the effective use of the computer to create,
modify or document an engineering modify or document an engineering
design.design.
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Reason using CADReason using CAD
There areThere are several important reasonsseveral important reasons for for
using a CAD system to support theusing a CAD system to support the
engineering design function:engineering design function:
1.1. To increase the productivity of the designer.To increase the productivity of the designer.
2.2. To improve the quality of the design.To improve the quality of the design.
3.3. To improve design documentation.To improve design documentation.
4.4. To create a manufacturing data base.To create a manufacturing data base.
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Design ProcessDesign Process
DEFINITION:DEFINITION:
A decision making process using theseA decision making process using these
elementselements
Basic science, mathematics and engineeringBasic science, mathematics and engineering
science.science.
To enable available resource (e.g material,To enable available resource (e.g material,
people).people). To meet a desired, measurable goal (usuallyTo meet a desired, measurable goal (usually
resulting in a product or system).resulting in a product or system).
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Design ProcessDesign Process
The design processThe design processGenerally process of design is characterizedGenerally process of design is characterized
byby ShigleyShigley as an iterative process whichas an iterative process which
consists of the following six phases:consists of the following six phases:1.1. Recognition of needRecognition of need
2.2. Definition of the problemDefinition of the problem
3.3. SynthesisSynthesis
4.4. Analysis and optimizationAnalysis and optimization5.5. EvaluationEvaluation
6.6. PresentationPresentation
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Recognition of need
Definition of problem
Presentation
Synthesis
Analysis & Optimization
Evaluation
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Design ProcessDesign Process
1. Recognition of need1. Recognition of need
-- problem existsproblem exists -- corrective actioncorrective action cancan
be taken in the form of a design solution.be taken in the form of a design solution.-- identifying some defectidentifying some defect in a currentin a current
m/c by an engineer m/c by an engineer
-- perceiving of some new productperceiving of some new productopportunity by a salespersonopportunity by a salesperson
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Design ProcessDesign Process
2. Definition of the problem2. Definition of the problem
-- a thorougha thorough specificationspecification of the item toof the item to
be designed.be designed.-- it includes theit includes the physical characteristicsphysical characteristics,,
function, cost, qualityfunction, cost, quality andand operatingoperating
performance.performance.
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Design ProcessDesign Process
3. Synthesis AND3. Synthesis AND
4. Analysis & optimization4. Analysis & optimization
-- areare closely related & highly interactiveclosely related & highly interactive inin
design process.design process.-- developmentdevelopment of a certain product designof a certain product design
-- conceptualized by theconceptualized by the designer, analyzed,designer, analyzed,improved through this analysis procedure,improved through this analysis procedure,
redesigned, analyzed againredesigned, analyzed again & so on& so on (repeated).(repeated).-- until the design has been optimized within theuntil the design has been optimized within theconstraints imposed on the designer.constraints imposed on the designer.
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Design ProcessDesign Process
5. Evaluation5. Evaluation
-- measuring the designmeasuring the design against theagainst the
specifications established in the problemspecifications established in the problemdefinition phase.definition phase.
-- often requires theoften requires the fabrication & testingfabrication & testing
of a prototype model to assessof a prototype model to assess operatingoperating
performance, quality, reliabilityperformance, quality, reliability & etc.& etc.
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Design ProcessDesign Process
6. Presentation6. Presentation
-- concerned with the doc. of the design byconcerned with the doc. of the design by
means of means of drawings, materialdrawings, materialspecifications, assembly listsspecifications, assembly lists & etc.& etc.
-- design data basedesign data base is created.is created.
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ApplicationApplication
Application of computers in designApplication of computers in design
A CAD system can be beneficially be used in 4A CAD system can be beneficially be used in 4
phases of the design process:phases of the design process:1.1. Geometric modelingGeometric modeling (Synthesis)(Synthesis)
2.2. Engineering analysisEngineering analysis (Anly & Opt)(Anly & Opt)
3.3. Design review & evaluationDesign review & evaluation (Evaluation)(Evaluation)
4.4. Automated draftingAutomated drafting (Presentation)(Presentation)
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Recognition of need
Definition of problem
Presentation
Synthesis
Analysis & Optimization
Evaluation
Geometric modeling
Engineering analysis
Design reviewand evaluation
Automated drafting
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Design Process using CADDesign Process using CAD1.1. Geometric modelingGeometric modeling
-- develop adevelop a mathematical descriptionmathematical description (model (model--
contained in computer memory)contained in computer memory) of theof the
geometry of an object.geometry of an object.-- includesincludes creatingcreating new geometric models fromnew geometric models from
basic building blocks, moving the imagesbasic building blocks, moving the images
around the screen, zooming in on certainaround the screen, zooming in on certain
features of the imagefeatures of the image & etc.& etc.-- geometric models in CAD can also begeometric models in CAD can also be
clasisified :clasisified : wirewire--frame modelsframe models or or solid modelssolid models
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WIRE FRAME MODEL
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SOLID MODEL
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Design Process using CADDesign Process using CAD
2. Engineering Analysis2. Engineering Analysis
-- the form of the form of stressstress--strain calculations,strain calculations,
heat transfer analysisheat transfer analysis or or dynamicdynamicsimulation.simulation.
-- 2 examples2 examples of the software typicallyof the software typically
offered on CAD systems areoffered on CAD systems are massmass
propertiesproperties && FiniteFinite--Element AnalysisElement Analysis
(FEA)(FEA)..
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Design Process using CADDesign Process using CAD
Examples of Engineering AnalysisExamples of Engineering Analysis
Mass properties analysisMass properties analysis
Interface checkingInterface checking Tolerance analysisTolerance analysis
Finite element analysisFinite element analysis
Kinematic and dynamic analysisKinematic and dynamic analysis
DiscreteDiscrete--event simulationevent simulation
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Design Process using CADDesign Process using CAD
3. Design review & evaluation3. Design review & evaluation
-- some of the CAD features:some of the CAD features:
a)a) Automatic dimensioning routinesAutomatic dimensioning routinesb)b) Interference checking routinesInterference checking routines
c)c) Kinematics routinesKinematics routines
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Design Process using CADDesign Process using CAD
4. Automated drafting4. Automated drafting
-- to prepareto prepare highly accuratehighly accurate engineeringengineering
drawings quickly.drawings quickly.-- estimate that a CAD system increasesestimate that a CAD system increases
productivity in drafting function by aboutproductivity in drafting function by about
5 fold5 fold over over manual preparationmanual preparation of theof the
drawings.drawings.
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Design Process using CADDesign Process using CAD
A typical CAD systemA typical CAD system
Consists of the following components:Consists of the following components:
1.1. One or more design workstationsOne or more design workstations2.2. Processor Processor
3.3. Secondary storageSecondary storage
4.4. Plotter / other output devicesPlotter / other output devices..
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CAMCAM
CAMCAM ±± COMPUTER AIDEDCOMPUTER AIDED
MANUFACTURINGMANUFACTURING
DefinitionDefinition
the effective use of computer technology inthe effective use of computer technology in
manufacturing planning and control.manufacturing planning and control.
2 categories:2 categories:
Manufacturing planningManufacturing planningManufacturing controlManufacturing control
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CAMCAM
Manufacturing PlanningManufacturing Planning
CAPPCAPP
Computer Computer--assisted NC part programmingassisted NC part programming Computerized machinability data systemsComputerized machinability data systems
Development of work standardsDevelopment of work standards
Cost estimatingCost estimating
Production and inventory planningProduction and inventory planning
Computer Computer--aided line balancingaided line balancing
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CAMCAM
Manufacturing ControlManufacturing Control
Process monitoring and controlProcess monitoring and control
Quality controlQuality control Shop floor controlShop floor control
Inventory controlInventory control
JIT production systemsJIT production systems
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CAMCAM
Areas of usageAreas of usage
In mechanical engineeringIn mechanical engineering
In machiningIn machining In electronic design automation (printed circuitIn electronic design automation (printed circuit
board (PCB) and integrated circuit designboard (PCB) and integrated circuit design
data for manufacturing)data for manufacturing)
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CIMCIM
CIMCIM ±± COMPUTER INTEGRATEDCOMPUTER INTEGRATED
MANUFACTURINGMANUFACTURING
Definition:Definition:
is a method of manufacturing in which the entireis a method of manufacturing in which the entire
production process is controlled by computer.production process is controlled by computer.
Typically, it relies on closedTypically, it relies on closed--loop controlloop control
processes, based on realprocesses, based on real--time input fromtime input fromsensors. It is also known assensors. It is also known as flexible designflexible design
and manufacturingand manufacturing..
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CIMCIM
Three components distinguish CIM fromThree components distinguish CIM from
other manufacturing methodologies:other manufacturing methodologies:
means for data storage, retrieval,means for data storage, retrieval,
manipulation and presentation;manipulation and presentation;
mechanisms for sensing state and modifyingmechanisms for sensing state and modifying
processes;processes;
algorithms for uniting the data processingalgorithms for uniting the data processingcomponent with the sensor/modificationcomponent with the sensor/modification
component.component.
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CIMCIM
Areas of usageAreas of usage
In mechanical engineeringIn mechanical engineering
In electronic design automation (printed circuitIn electronic design automation (printed circuit
board (PCB) and integrated circuit designboard (PCB) and integrated circuit design
data for manufacturing)data for manufacturing)
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Factory
operation
Design
Mfg.
planningBusiness
functions
Mfg. control
Scope of CAD/CAM
Scope of CIM
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Factory
operation
Design
Mfg.
planningBusiness
functions
Mfg. control
CADGeometric modelingEngineering analysisDesign review and evaluation
Automated drafting
CAMCost estimationCAPPNC part programmingComputerized work stds.MRP, capacity planning
ComputerizedBusiness SystemsOrder entryAccountingPayrollCustomer billing
CAMProcess controlProcess monitoringShop floor control
Computer-aided inspection
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Mass properties AnalysisMass properties Analysis
Involves computation of such features of aInvolves computation of such features of a
solid object as its volume, surface area,solid object as its volume, surface area,
weight, and center of gravity.weight, and center of gravity.
Applicable in mechanical design.Applicable in mechanical design.
It required painstaking and timeIt required painstaking and time--
consuming calculation by the designer.consuming calculation by the designer.
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Interface checkingInterface checking
CAD software examines 2D geometricCAD software examines 2D geometric
models consisting of multiple componentsmodels consisting of multiple components
to identify interfaces between theto identify interfaces between the
components.components.
It is useful in analyzing mechanicalIt is useful in analyzing mechanical
assemblies, chemical plants and similar assemblies, chemical plants and similar
multicomponent designs.multicomponent designs.
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Tolerance analysisTolerance analysis
Software for analyzing the specified tolerance of Software for analyzing the specified tolerance of
a product¶s components is used for the followinga product¶s components is used for the following
functions:functions:
To assess how the tolerances may affect theTo assess how the tolerances may affect theproduct¶s function and performance,product¶s function and performance,
To determine how the tolerances may influence theTo determine how the tolerances may influence the
ease or difficulty of assembling the product, andease or difficulty of assembling the product, and
To assess how variations in component dimensionsTo assess how variations in component dimensionsmay effect the overall size of the assemblymay effect the overall size of the assembly
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Finite element analysisFinite element analysis
Use to aid in stressUse to aid in stress--strain, heat transfer strain, heat transfer
fluid flow, etc.fluid flow, etc.
FEA is a numerical analysis technique for FEA is a numerical analysis technique for determining approximate solutions todetermining approximate solutions to
physical problems describe by thephysical problems describe by the
differential equations that are very difficultdifferential equations that are very difficult
or impossible to solve.or impossible to solve.
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Kinematic and dynamic analysisKinematic and dynamic analysis
Kinematic analysis involves the study of Kinematic analysis involves the study of
the operation of mechanical linkages tothe operation of mechanical linkages to
analyze their motions.analyze their motions.
Dynamic analysis extends kinematicDynamic analysis extends kinematic
analysis by including the effect of theanalysis by including the effect of the
mass of each linkage member andmass of each linkage member and
resulting acceleration forces as well asresulting acceleration forces as well asany externally applied forces.any externally applied forces.
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DiscreteDiscrete--event simulationevent simulation
Used to model complex operationalUsed to model complex operational
systems such as a manufacturing cell or asystems such as a manufacturing cell or a
material handling system, as event occur material handling system, as event occur
at discrete moments in time and affect theat discrete moments in time and affect the
status and performance of the system.status and performance of the system.
ExampleExample
Part arriving for processingPart arriving for processing
Machine breakdownMachine breakdown
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ASSIGNMENTASSIGNMENT
DTP 5DTP 5
DKM 5DKM 5
DTP 3 (KSS)DTP 3 (KSS)
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DTP 5DTP 5
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DKM 5DKM 5
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DTP 3 (KSS)DTP 3 (KSS)
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A. Define as follows:A. Define as follows:1.1. Wire frame (3D)Wire frame (3D)
2.2. Surface Modeling(3D)Surface Modeling(3D)
3.3. Solid Modeling(3D)Solid Modeling(3D)
B. Explain basic concept of B. Explain basic concept of F inite Element F inite Element
Analysis ( F EA)Analysis ( F EA) in constructed modelin constructed modelanalysis.analysis.
C. Discuss the differences between 2C. Discuss the differences between 2--DD
graphic and 3graphic and 3--D graphic in CAD engineeringD graphic in CAD engineering
D. Brief shortly about CATIA and PRO ENGINEER.D. Brief shortly about CATIA and PRO ENGINEER.
Note: Include with your Note: Include with your REFERENCES ! REFERENCES !
Due date: 3rd August 2008.Due date: 3rd August 2008.
ASSIGNMENT # 1 (DEM 6)ASSIGNMENT # 1 (DEM 6)
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ASSIGNMENT # 1 (DTP5)ASSIGNMENT # 1 (DTP5)
A. Define as follows:A. Define as follows:
1.1. Wire frame (3D)Wire frame (3D)
2.2. Surface Modeling(3D)Surface Modeling(3D)
3.3. Solid Modeling(3D)Solid Modeling(3D)
B. Explain basic concept of B. Explain basic concept of F inite Element F inite Element
Analysis ( F EA)Analysis ( F EA) in constructed modelin constructed model
analysis.analysis.
Note: Include with your Note: Include with your REFERENCES ! REFERENCES !
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ASSIGNMENT # 1 (DKM5)ASSIGNMENT # 1 (DKM5)
A. Discuss the differences between 2A. Discuss the differences between 2--DD
graphic and 3graphic and 3--D graphic in CAD engineering.D graphic in CAD engineering.
B. Explain basic concept of B. Explain basic concept of F inite Element F inite Element
Analysis ( F EA)Analysis ( F EA) in constructed model analysis.in constructed model analysis.
Note: Include with your Note: Include with your REFERENCES ! REFERENCES !