CAD/CAM - College of Engineering & Engineering Technology

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14 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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CAD/CAM (CIM)

Computer Aided Design/Computer Aided Manufacturing

(Computer Integrated Manufacturing)

Meung J. Kim, Ph.D, Professor

Mechanical Engineering

Northern Illinois University

DeKalb, IL 60115


2013

Objectives


Introduction to CAD/CAM


Current Development Activities


References for Details

Contents

Part I. Introduction

Part II. CAD

Part III. CAM

Part IV. CAD/CAM Integration

Part V. Current Development

Part I: INTRODUCTION

What is CAD/CAM (or CIM) Technology?


CAD: makes representation of
products and perform analysis of the
design
(about 70% of project)


CAM: prepare manufacturing
processes and drive machine tools
(about 30% of project)


CIM: CAM/CAM + Other Activities
Such As Operations Management and
Master Storage and Handling.

History of CAD/CAM/CIM

Operational Flow of CIM

The classification of the manufacturing system of a company should identify the
activities in the three major
process segments
(ie, design, manufacturing
control and planning, and production) in CIM wheel.

Business
segment

Process
segment

Infrastructure &
resources

Manufacturing System Classification

Design Considerations

Design

Functionality

Economics


Part must function correctly and last
reasonable duration of time


Functional considerations involve
weight, strength, thermal properties,
kinematics, and dynamics, etc.


Performance evaluation against design
specifications


This is determined by a part’s


geometry


material properties


environment


Part must be designed as closely as
possible to the design specifications


The economic factors include


materials


processing costs


marketing details

Part II: CAD

CAD Technologies

Evolution

1950s:

SAGE System
(Analyze Radar Image with Light
-
pen)

1962:

SketchPad at MIT
(Interactive Graphics with SketchPad)

1960s:

Digital Equipment Corporation, Control Data, IBM, Univac, Applicon,

Calma, ComputerVision, Intergraph
(Calma Graphics System, ComputerVision,

CADD System, IBM CADAM, CATIA, Intergraph Graphics System)

1970s:

Recognized as Indispensible Tools to Improve Productivities especially

in ME, EE, and CE

1980s
-

1990s: Widely Spread Due To Lower Price and availability of PC

1990s
-

:

Network Based such as Internet, LAN, and WAN

2000s
-

: Cloud Computing

CAD Structure



Input Device



Output Device



CPU



Memory



Storage Device



Communication Device

Haptic I/O

Data Glove

CAD Technological Issues


from Hardware Perspective

Graphics Terminal Performance

(Display Technology)

Computer Performance

Utilization of Existing
Leading
-
Edge Technologies
like Artificial Intelligence


(Pattern Recognition, Planning, Voice
Recognition, Robot Control, Fault Diagnosis,
and Expert Systems)

Electronic Image
-
> Visual Image

(CRT, LCD, LED with vector/raster painting)

Storage of Display Image Format

(Point
-
, Vector
-
, Relationship
-
Oriented Storage)

Production of Display Image from
Design

Execution
of Mathematical Functions Needed
to Translate Stored Images into Display and to
Manipulate Vector Representation Designs in
Storage. Some Efforts are:



Math
-
Coprocessor in PCs



Pre
-
Fetch Methods to reduce I
-
time in Intel 8086
-
Family of Processors



RISC (Reduced Instruction Set Computer) to
reduce I
-
time



Parallel Processors



Super Computers

CAD Technological Issues


from Software Perspective

Geometric Modeling

Parametric and
Variational Design

Integrated Data Base
Management and Optimization



Multi
-
View 2D Modeler



3D Wire Frame Modeler



3D Surface Modeler



Solid Modeler
-
>
CAM



Stress Analysis



CFD



Kinematics Analysis for Moving Parts



Simple Analysis like Area/Volume, Mass Calculations



Artificial Intelligence (AI) which works with facts and rules
from which they can make deductions: Pattern Recognition,
Planning, Voice Recognition, Robot Control, Fault Diagnosis,
and Expert Systems.

* Virtual Reality (VR) Technology



Scaling



Rotation



Translation



Reflection



Visualization



Editing



Dimensioning and Labeling



Shading



Real
-
Time Animation

Rendering

Analysis:
Help Engineers to
Determine Feasibility of Design: FEM
and other computational methods



CAD Drawing



Engineering Analysis



Modeling



NC



Robots



Process Planning



Management



IGES



…..

Feature
-
Based Design

CAD Data Exchangeability


Since the
IGES
was first developed under the guidance of National Bureau of Standards (NBS) [87]
in 1979, CAD/CAM data exchange had leaped beyond IGES. This brought about an effort from the
international community to introduce a single international standard for graphics data exchange. As
a result the Standard for the Exchange of Product Data Models (
STEP
, officially the ISO standard
10303) was introduced. The STEP is a series of International Standards with the goal of defining
data across the full engineering and manufacturing life cycle to produce a single international
standard for product data exchange. There are currently several standards like U.S.’ IGES, France’s
SET
, and Germany’s
VDA
-
FS
.


The

International

Organization

for

Standardization

(ISO)

[
88
]

is

a

worldwide

federation

of

national

standards

bodies

from

some

100

countries,

one

from

each

country

and

established

in

1947
.

In

USA

an

organization

called

The

National

Institute

of

Standards

and

Technology

(NIST),

formerly

the

National

Bureau

of

Standards,

was

established

by

Congress

in

1901

to

support

industry,

commerce,

scientific

institutions,

and

all

branches

of

Government
.

For

nearly

100

years

the

NIST/NBS

laboratories

have

worked

with

industry

and

government

to

advance

measurement

science

and

develop

standards
.



There is another collaborative effort under the project
INDEX
(Intelligent Data Extraction) at
Manchester Visualization Center of University of Manchester [63]. This is also concerned with
exchangeability of CAD/CAM data among different systems that provides a flexible software tool
set.

Geometric Modeling:
Object Geometry


Principles of Orthographic Projection

Modeling Methodology


Boundary Representation (B
-
rep)


Constructive Solid Geometry
(CSG)


Sweep Representation


Analytic Solid Modeling
(ASM)


Pure Primitive Instancing (PPI)


Cell Decomposition


Spatial Enumeration


Octree Encoding

Modeling Techniques


Extrude


Revolve


Sweep


Blend

Analyses


Structural Analyses


Heat Transfer Analyses


Fluid Analyses


Coupled
-
Field Analyses





Linear and Nonlinear
Analyses

Choosing a Solid Modeler for

CAD/CAM Integration



Flexibility
(must be able to handle all kinds of objects)



Robustness
(should produce a consistent and proper solid)



Simplicity
(must be simple and user friendly)



Performance
(speed is important that should be improved with software methodology and


hardware)



Economy
(solid modeler is expensive, but will pay for itself as time goes on with


CAD/CAM)

Part III: CAM

The figure above shows some geometries to consider for tool
-
path generation.
There are various approaches to determine the tool path. For example, the
surface normal and tangent vectors
at each point.

Tool Path Geometry

Milling Machines

CAM Technologies

History



1909: Automation by Ford Automobile Company
(Mass Production)




1923: Automatic Transfer Machines
at Morris Engine Factory, England



1952:
Numerical Controls (NC)

for tool positioning thru computer commands



1959: Control Digital Computer

at Texaco refinery, Texas



1960:
Robot

Implementation

-

Unimate based on NC principles



1965: Production
-
Line Computer Control

(IBM developed plcc for circuit boards)



1970:
Direct Numerical Control
(DNC)
--
> Multiple
-
Machine Computer Control


(Japanese National Railways: several machine tools under simultaneous control of a computer)



1970
-
1972:
Computer Numerical Control
(CNC)
: each machine tool has its own memory (PC)



1975
-
1980:
Distributed Numerical Control
(DNC)
: a main computer downloads NC programs to

applicable machine. This is the key concept to CAM advances.



1980s: Cellular Manufacturing
: A reduction of combinations in job shop control is achieved by identifying

families of parts that can be produced on a subset of equipment in the job shop. This determination of


families and equipment is most often done by group technology. Then the cell control computer download

NC programs and effect material handling between machines, frequently thru robot transfers.



-

: Flexible Manufacturing Systems
: The idea of using a set of machines to produce a relatively

wide variety of products, with automatic movement of products through any sequence of machines, including

testing, is the heart of the flexible manufacturing systems.


2000s:
3D Printing

Manufacturing Cell

Computers in Manufacturing

Manufacturing

Control


Computer Control

(late 1950s)

Numerical Controls (NC)

Numerical control (NC) is a concept of machine control that consists of several steps such
as development of manufacturing plan for a part, programming numerical control
instructions, process the program to locate the tool path, and post
-
process for a specific
machine tool. NC activities consist of NC machines like CNC and DNC and processor
language like APT in addition to the human operator.

Robots in Manufacturing

Industrial robots have been used in the manufacturing
more than two decades. It is no doubt that robots will
play a crucial role in the future manufacturing.
Though, there are still quite challenging technologies
to overcome in this field of technology such as:



vision system



position sensing



hand tactile sensing



dexterous linkage



control methodology.

Sensing/Measuring/Quality Controls

Sensing and measuring are also essential part of
manufacturing such as quality controls and had been
integrated into CAD/CAM.

CAM Technological Issues


from Software Perspective

Concurrent Engineering

Manufacturing Planning
and Control

Robotics



Axiomatic Design



DFM



Design Science



DFA



Taguchi Method



MPDR, Group Technology



FMEA



Production Control



Cellular Manufacturing



JIT Manufacturing

Measurement and Verification



Hierarchical Code



Attribute Code



Process Planning (CAPP)



Manual Approach



Variant Approach



Generative Approach

Group Technology

Computer Control and PLC



Sensing



Measuring



Quality Control



Timing



Priority Interrupts



Real
-
Time, Multi
-
Tasking Operating Systems



Numerical Control (NC)



NC/CNC/DNC Machines



NC Programming


APT,ADAPT,EXAPT,etc.

Artificial
Intelligence

Artificial Intelligence
(Expert Systems)

Probably the most prominent artificial intelligence is the
expert system
, which
mimic the human intelligence through a stored knowledge
-
based data.

Expert system uses the AI technology to formulate facts and rules in a given
field, based on specialists’ knowledge of that field, make that information
available to designers.

As much as the concept of expert systems are so attractive, it is far more
expensive

to develop, store, and access a major subset of the entire body of
knowledge on a given topic than provide a limited subset in a traditional form.
This is one of the major reasons that expert systems are still not fully adopted in
CAD/CAM. Another reason is that expert systems are more difficult to test
because there is no limit to the number of different requests which might make
to users.


Despite of the difficulty in building and validating expert systems and the
resources required to support their use, their
high value
in CAD/CAM
applications will drive their further development to support design and use in the
future. Some of the current tasks performed by humans will then be replaced by
expert systems such as design optimization and process planning. Any major
CAD/CAM vendors who are not actively developing such products would risk
their place in the future market.

Part IV: CAD/CAM Integration

Concurrent Engineering

CE is an approach to design
and manufacturing activities,
which tries to complete the
design
in parallel to
process
planning, field
-
support,
quality control, and other
manufacturing
-
related
activities. Its mission is to
design and optimize the
product under the constraints
such as functionality,
producibility, and cost.




Axiomatic design



Design for manufacturing (DFM)



Design science



Design for assembly (DFA)



Taguchi method for robust design



Manufacturing planning and control



Computer Aided Process Planning (CAPP)



Computer
-
aided DFM
(design for manufacturing)



Group technology (GT)



Failure
-
mode and effects analysis



Value engineering

Group Technology (GT)

An essential aspect of CAD/CAM integration is the integration of
information

used in design and manufacturing in all departments of an
organization. The group technology provides a means to integrate this
information about parts that is easy to implement in computers and
analyze. There are several classification (or coding) methods like
hierarchical code, attribute code, and hybrid code.

Manufacturing Planning and Control

There are several approaches
to achieve the efficient
process planning such as:



manual approach



variant approach



generative approach.


Manufacturing planning and control
activities involve demand forecasts,
master production schedule (or
aggregate planning), material
requirement planning (MRP), capacity
planning, shop
-
floor control, and quality
control (QC). A widely available
commercial software is MAPICS from
IBM.

Computer Aided Process Planning (CAPP)

Process planning consists of a set of instructions that describes how to
manufacture a part or build an assembly according to the given
manufacturing specifications. Since this is the link between CAD and
CAM, it is one of the key elements in CAD/CAM integration and is
drawing more attentions of CAD/CAM developers in today’s competitive
market. Computer
-
aided process planning (
CAPP
) is now part of ongoing
current efforts in integration of CAD and CAM.

Cellular/Just
-
In
-
Time Manufacturing

Cellular manufacturing is
the organized manufacturing
activity such that a family of
parts or assembly can be
efficiently fabricated in a
cell (i.e., a group of people
and manufacturing
machines).

As the competition in manufacturing
market has increased, many firms
have realized the
cellular
manufacturing

and
just
-
in
-
time (JIT)
manufacturing

can provide
significant advantages such as
reduced through
-
put, reduced work
-
in
-
progress inventory, reduced
materials handling, and improved
quality.

As it says JIT
manufacturing is to deliver
the right number of parts to
the right shop
-
floor
operation at the right time.

CAD/CAD System Integration


CAD system integration involves the
transfer of designs among different
systems. Integration with CAM is
probably more difficult than
CAD
-
CAD integration
.
Larger vendors normally
offers CAM packages as well, so it is possible to pass a
design data into machine tool control languages like
APT. There were also products which could produce
APT or other languages from IGES
*

(Initial Graphics
Exchange Specification) designs.

CAD systems are the starting point for
production of goods and there was
considerable motivation to provide a
means for information derived from the
design process to migrate to the
remainder of manufacturing operation.
This included integration of CAD
systems themselves, integration with
computer
-
aided manufacturing
systems, and integration with
manufacturing information systems.

* IGES (Initial Graphics Exchange Standard) was developed under the guidance of the National Bureau of Standards in 1979
in order to provide a tool for graphics data exchange in neutral format. In addition, several other standards were also
proposed such as PDES (Product Data Exchange Specification), EDIF (Electronic Design Interface Format), GKS
(Graphics Kernel System), and CORE. The most widely supported is IGES and currently many companies like Boeing
Company, Sandia National Laboratories, and General Motors use IGES in production. Octal, Inc. provides an interesting
alternative to IGES which is the direct conversion approach over “neutral format” schemes and is recognized as the leader
in CAD database interchange. Octal provides many direct converters among different CAD systems, for example, Anvil
4000 to/from CADAM and CATIA to/from Intergraph IGDS.

Part V: CURRENT DEVELOPMENT

CAD

Graphics, Visualization, Geometric Modeling

Modeling



Virtual reality



Computational geometry



Grammatical design and geometric representation



NURBS (Non
-
Uniform Rational B
-
Spline)


Rendering



Virtual reality



Computational geometry



Grammatical design and geometric representation



NURBS (Non
-
Uniform Rational B
-
Spline)


User Interfaces



Virtual reality Modeling Language (VRML)

High Performance Architectures

Theory of Design

Hierarchical Sequential Interactive Synthesis

Layout
-
Driven Logic Synthesis

Feature
-
Based Design

Design Methodologies and Technologies

Integration of Distributed Computer
-
Controlled Operations via Data Transfer in Network

Distributed Simulation via Network

Web
-
Based Electronic Design

Analog CAD



Field
-
Programmable Gate Arrays (FPGA) Synthesis



Multi
-
Chip Modules (MCM)



Integrated Circuit (IC) including VLIC



Near
-
Optimal Approximation Algorithms

Hardware
-
Software Co
-
Simulation and Co
-
Design

Virtual Environments for Design

Virtual Environments for Ergonomic Design

Knowledge
-
Based Systems (or expert systems) with Concurrent Engineering


Development of Means for Design Coordination or Integrated Design: CE

Optimization

Management and Practice of Applications Development

Case
-
Based Reasoning

Data Management Tools

Digital Archive Development Based on Pattern Recognition and Typified Protocols

Information Retrieval and Manipulation

Development of Part Library

Improvement of Product Information Management

Verification Interacting with Synthesis

Intelligent Design Support for Artificial Intelligence and Advanced Computing Techniques

CAE

Development of Computational Methods

Stereo Modeling

Scalable Computing for Large, Complex, and Advanced Processing with Shared
Computational Resources

Mesh Generation in support of Numerical Methods

Application of Iterative Design Principles in Development of
Processes and Products

CAM

Machines and Machining Technologies

Nondeterministic Abstract Machines

Solid Manufacturing

Feature
-
Based Machining

High Strength Composite Manufacturing Techniques

Automated Milling, Welding, Coating, Painting, etc.

Industrial Lasers

Mobile Robots

Computer
-
Aided Production Engineering (CAPE)

Process and Manufacturing Planning

Intelligent Product Manuals

Enterprise Information Management

Product Data Management

Automated Layout of Three
-
Dimensional Products

Optimization:
Development of Manufacturing Software in Manufacturing

Sensing and Inspection

Machine Vision

Remote Sensing and Diagnostic Imaging

Automated Visual Inspection

Telerobotics

Product Quality Improvement

Nondestructive Testing Techniques

Virtual Reality (VR)

Virtual Manufacturing

Virtual Assembly

Virtual Environments for Telerobotics

Calibration in Virtual Environments

Integrated Manufacturing

Integrated Product Development

Rapid Prototyping (RP)

Baseline Development Areas



Product representation through feature
-
based
modeling



Knowledge
-
based applications supporting the
entire life cycle



Engineering environment built around object
-
oriented, distributed computing systems



Direct manufacturing incorporating present
practices and freeform fabrication

Reverse Engineering


Rapid Response Prototyping (RRP)


Rapid Response Testbed

Present framework

Present Applications



Development and verification of advanced
RRM application



Vendor product integration and interaction
capability



Integrated use and management of core
information models and application software



Concurrent information sharing



Part family specialization



Early validation of RRM requirements

Integrated Manufacturing (cont’d)

Rapid Prototyping (RP)

Present framework

Present Applications



Reference architecture



Environment



Knowledge
-
based application



Digital prototyping (or computational
prototyping)



Computerized milling, forming, and spraying



Stereolithography

R
e
f
e
r
e
n
c
e
s


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System,” in
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J. W. Boyse and M. Pickett, Eds., Plenum
Press, New York,
1985.

2. Baumgart, B. G.: “Winged
-
Edge Polyhedron Representation,” STAN
-
CS
-
320, Computer Science Department,
Stanford University, Palo Alto, Calif., May 1974.

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The Mathematical Basis of the UNISURE CAD System,
Butterworths, London, 1986.

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IEEE
Computer Graphics and Applications,
March 1982, pp. 27

40.

5.
Braid, I. C., R. C. Hillyard, and I. A. Stroud: “Stepwise Construction of Polyhedra in Geometric Modeling,” CAD
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A Study in Hole Design,”
Computer and
Industrial Engineering,
vol. 6, no. 2, pp. 91

102, 1982.

7. Farm, G.:
Curves and Surfaces for Computer
-
Aided Geometric Design,
2d ed., Academic Press. San Diego, 1989.

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in
Advances in Computer
-
Aided Manufacture,
D. McPherson, Ed., Elsevier Scientific Publishers, New York, 1977,
pp. 137

151.

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Software for Discrete Manufacturing,
1. P.
Crestin and J. F. McWaters, Eds., Elsevier Science Publishers, North
-
Holland, 1986.

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1.
Chang, “FRAPP: Automated Feature Recognition and Process Planning from Solid
Model Data,”
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1988, pp. 529

536.

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Database,”
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August 1988, pp.278

287.

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CAD/CAM Techniques.
Reston Press, Reston, Va., 1986.

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Solid Modeling by Computers: Theory and Applications,
1. W. Boyse and M. Pickett, Eds., Plenum Press, New York, 1985.

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An Introduction to Solid Modeling,
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San Francisco, Calif.

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-
Based Object Decomposition for Finite
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-
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-
135.

Conclusions


Design/Manufacturing/Verification


Time/Cost


Robot and Sensors in Product with AI


Data Exchangeability in All Steps


Integration over Network (LAN, InterNet)


Directions of Government Agencies

Directions of Government Agencies
(Conclusions)


Focus on high
-
risk, high
-
payoff technologies with broad
application


Address problems of sufficient size and scope to have a
substantial effect


Achieve meaningful and measurable goals and ensure the
development of technology that can be implemented and
used


Build on the strengths of particular government agencies in
assigning responsibilities


** It clearly shows how the manufacturers should direct their efforts
to stand ahead of others by prioritizing their
focuses

with
effects

in
mind

and achieving
measurable

goals in
cooperation

with closely
related government agencies.

Already Identified Goals of Government
Agencies (Conclusions)


Agile manufacturing and flexible manufacturing


Rapid prototyping (virtual and physical) and direct
fabrication


Intelligent controls and sensors


Especially advanced sensors, intelligent controls and innovative actuators
are emphasized which will be vital elements in future manufacturing
equipment and production systems.