CHAPTER A - INTRO

8/7/2019 CHAPTER A - INTRO

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J4123J4123--RPTKRPTK

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.




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))




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 %



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.



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.



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).




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



Recognition of need

Definition of problem

Presentation

Synthesis

Analysis & Optimization

Evaluation




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




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.




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.




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.




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.



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)



Recognition of need

Definition of problem

Presentation

Synthesis

Analysis & Optimization

Evaluation

Geometric modeling

Engineering analysis

Design reviewand evaluation

Automated drafting



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



WIRE FRAME MODEL



SOLID MODEL



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)..




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




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




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.




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..



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



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



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



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)



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..



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.





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)



Factory

operation

Design

Mfg.

planningBusiness

functions

Mfg. control

Scope of CAD/CAM

Scope of CIM



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





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.



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.



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



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.



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.



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



ASSIGNMENTASSIGNMENT

DTP 5DTP 5

DKM 5DKM 5

DTP 3 (KSS)DTP 3 (KSS)



DTP 5DTP 5



DKM 5DKM 5



DTP 3 (KSS)DTP 3 (KSS)



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)




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)


Analysis ( F EA)Analysis ( F EA) in constructed modelin constructed model

analysis.analysis.





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.


Analysis ( F EA)Analysis ( F EA) in constructed model analysis.in constructed model analysis.


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CHAPTER A - INTRO

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