Product Design & CAD

7/28/2019 Product Design & CAD

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Dr Chong

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Manufacturin su ort s stemsManufacturin su ort s stems

Procedures & systems used by a firm to manage production

& solve the technical and logistic problems (products design,

processes planning, materials ordering, work-in-process

control, products delivering to customer)

Many of these functions can be automated using computer

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systems computer-aided design (CAD) , computer-

integrated manufacturing (CAM)

Any design activity that involves the effective use of the

computer to create, modify, analyze, or document an

Terminology ExplanationCAD(Computeraideddesign) Usesthecomputertosupportthedesign

engineeringfunction

CAM(Computeraidedmanufacturing) Usesthecomputertosupport

manufacturingengineeringactivities

CIM(Computer

integrated manufacturing) Includes all

of

CAD

/CAM

Embracesthebusinessfunctionsofamanufacturingfirm

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1 Product Design and CAD

2 CAD System Hardware

3 CAM, CAD/CAM, and CIM

4 Quality Function Deployment

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The general process of

design is characterized

as an iterative process

consisting ofsix phases:

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1. Recognition of need - someone

recognizes the need that can besatisfied by a new design

2. Problem definition - s ecification of

the item

3. Synthesis - creation and

conceptualization

4. Analysis and optimization - the

concept is analyzed and redesigned

. -

original specification

6. Presentation - documenting thedesign (e.g., drawings)

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To increase the productivity of the designer;

To expand the available geometric forms in design -

wider range of mathematically defined shapes

possible;

-

engineering analysis possible, consideration of

more alternatives

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To improve design documentation - better drawings

an w manua ra ng

To create a manufacturing database - creation of

the design documentation also creates

manufacturing data

To promote design standardization - use of design

rules to limit the number of hole sizes, fasteners,etc.

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3. Geometric modeling

CAD system develops a

mathematical description of thegeometry of an object, called ageometric model

.

Mass properties, interferencechecking for assemblies, finiteelement modeling, kinematicanalysis for mechanisms

5. Design evaluation and review

Automatic dimensioning, errorchecking, animation

6. Automated drafting

Preparation of engineering drawingsquickly

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Wire-frame model

Solid model

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The hardware for a typical CAD system consists of the followingcomponents:

. ne or more es gn wor s a ons

2. Digital computer

3. Plotters, printers, and other output devices

4. Storage devices

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The interface between the computer and the user in the CADsystem

1. Communicate with the CPU

2. Continuously generate a graphical image

3. Provide digital descriptions of the image

4. Translate user commands into operating functions

5. Facilitate interaction between the user and the

system

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1. Host and terminal

Mainframe serves as host for graphics terminals

e or g na con gura on n e s an s w en

CAD technology was first developing

2. Engineering workstation

Stand-alone computer system dedicated to one user

Often networked for sharing data and plotters

3. CAD system based on a personal computer

PC with high-performance CPU and high resolutiongraphics display monitor

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Original CAD system configuration in 1970s and 1980s Host computer is a mainframe or large mini computer

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An en ineerin workstation is a stand-alone com uter

system dedicated to one user and capable of executinggraphics software and other programs requiring high-speed

computational power

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This is a personal computer with a high-performance CPUand high resolution graphics display screen

-

share files, output devices, and for other purposes

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The effective use of computer technology in manufacturing

planning and control

os c ose y assoc a e w unc ons n

manufacturing engineering, such as process

planning and NC part programming

CAM applications can be divided into two broad

categories:

. anu ac ur ng p ann ng2. Manufacturing control

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Computer-aided process planning (CAPP) Computer-assisted NC part programming

Computerized machinability data systems

Computerized work standards

Cost estimating

Production and inventory planning

Computer-aided assembly line balancing

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Process monitoring and control

Quality control

op oor con ro

Inventory control

Just-in-time production systems

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Concerned with the engineering functions in both designand manufacturing

activities by means of computer systems

Goal is to not only automate certain phases of design and

certain phases of manufacturing, but to also automate the

transition from design to manufacturing

In the ideal CAD/CAM system, the product design

spec ca on res ng n e a a ase wou e

automatically converted into the process plan for making

the product

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Includes all of the engineering functions of CAD/CAM

Also includes the firm's business functions that are related

Ideal CIM system applies computer and communications

technology to all of the operational functions and information

processing functions in manufacturing

From order receipt,

Through design and production,

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A systematic procedure for defining customer desires andrequirements and interpreting them in terms of product

A series of interconnected matrices are established between

customer requirements and the technical features of a

proposed new product

The matrices are a progression of phases in which customer

requirements are first translated into product features, then into

manufacturin re uirements and finall into ualit rocedures,

for controlling the manufacturing operations

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Shown as a series of matrices that relate customer

requirements to successive technical requirements in atypical progression

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1. Identify customer requirements

2. Identify product features needed to meet customer

3. Determine technical correlations among product features

4. Develop relationship matrix between customer

requirements and product features

5. Comparative evaluation of input customer requirements

6. Comparative evaluation of output technical requirements

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Documents

Product Design & CAD