intro cad 1
TRANSCRIPT
-
8/2/2019 Intro Cad 1
1/56
1
CAD/CAMComputer Aided Design and
Computer Aided Manufacturing
Introduction to CAD/CAM
-
8/2/2019 Intro Cad 1
2/56
2
CAD/CAM
CAD/CAM = Computer Aided Design and
Computer Aided Manufacturing. It is the
technology concerned with the use ofcomputers to perform design and
manufacturing functions.
-
8/2/2019 Intro Cad 1
3/56
Introduction
In general, a Computer Aided Design (CAD)
package has three components:
a) Design,
b) Analysis and
c) Visualization, as shown in the sketch. A
brief description of these components
follows.
3
-
8/2/2019 Intro Cad 1
4/56
a) Design: Design refers to geometric
modeling, i.e., 2-D and 3-D modeling,
including, drafting, part creation, creation ofdrawings with various views of the part,
assemblies of the parts, etc.
b) Analysis: Analysis refers to finite elementanalysis, optimization, and other number
crunching engineering analyses
4
-
8/2/2019 Intro Cad 1
5/56
c) Visualization:
Visualization refers to
computer graphics,
which includes:
rendering a model,
creation of pie charts,contour plots, shading
a model, sizing,
animation, etc. 5
-
8/2/2019 Intro Cad 1
6/56
6
Each of these three areas has been
extensively developed in the last 30 years.
Several books are written on each of thesesubjects and courses are available through
the academic institutions and the industry.
-
8/2/2019 Intro Cad 1
7/56
Most commercial CAD packages (software)
consist of only a single component: design
or analysis or visualization. However, a few
of the vendors have developed an integrated
package that includes not only these three
areas, but also includes the manufacturing
software (CAM).
7
-
8/2/2019 Intro Cad 1
8/56
Due to the large storage requirement,
integrated packages use either an UNIX
workstation or a mainframe platform, andnot the popular PC platform.
With the improvement in PC computing
speed, its only a matter of time before wesee an integrated package running on pc.
8
-
8/2/2019 Intro Cad 1
9/56
Computer Aided Manufacturing
(CAM) CAM is the next stage of CAD. A part
created in CAD can be downloaded and
manufactured, without a human handtouching the part.
The process is called CAM, and involves
CAD, Networking, and NC programming,as shown below.
9
-
8/2/2019 Intro Cad 1
10/56
10
-
8/2/2019 Intro Cad 1
11/56
Throughout the history of our industrial
society, many inventions have been
patented and whole new technologies haveevolved . Perhaps the single development
that has impacted manufacturing more
quickly and significantly than any previoustechnology is the digital computer .
11
-
8/2/2019 Intro Cad 1
12/56
Computer-aided design(CAD) is defined as
the application of computers and graphics
software to aid or enhance the productdesign from conceptualization to
documentation .
12
-
8/2/2019 Intro Cad 1
13/56
CAD. is most commonly associated with the
use of an interactive computer graphics
system , referred to as a CAD system .Computer-aided design systems are
powerful tools and in the mechanical design
and geometric modeling of products andcomponents .
13
-
8/2/2019 Intro Cad 1
14/56
14
CAD can be defined as the use of computer
systems to perform certain functions in the
design process.
CAM is the use of computer systems to
plan, manage and control the operations of
manufacturing plant through either direct or
indirect computer interface with the plants
production resources.
-
8/2/2019 Intro Cad 1
15/56
15
From CAM definition, the application of
CAM falls into two broad categories:1. Computer monitoring and control .
Computer ProcessProcessdata
Control signals
Computer ProcessProcess data
-
8/2/2019 Intro Cad 1
16/56
16
2. Manufacturing support application .
Control signalsComputer Mfg
operations
Process data
-
8/2/2019 Intro Cad 1
17/56
17
The Product Cycle and
CAD/CAMIn order to establish the scope and definition
ofCAD/CAM in an engineering environment
and identify existing and future related tools,a study of a typical product cycle is
necessary. The following Figure shows a
flowchart of such a cycle.
i l d if l
-
8/2/2019 Intro Cad 1
18/56
18
The Manufacturing Process
The Design Process
SynthesisAnalysis The CAD Process
The CAM Process
Design
needs
Design
definitions,
specifications,
and requirements
Collecting
relevant design
information and
feasibility study
Design
conceptualization
Design
modeling and
simulation
Design
analysis
Design
optimization
Design
evaluation
Design
documentation and
communication
Process
planning
Ordermaterials
Design and
procurement of
new tools
Production
planning
NC, CNC, DNC
programming
ProductionQuality
control
Packaging
Marketing
Shipping
Typical Product Life Cycle
-
8/2/2019 Intro Cad 1
19/56
19
The product begins with a need which is identified
based on customers' and markets' demands.
The product goes through two main processes from
the idea conceptualization to the finished product:
1. The design process.
2. The manufacturing process.
The main sub-processes that constitute the design process
are:1. Synthesis.
2. Analysis.
-
8/2/2019 Intro Cad 1
20/56
20
Implementation of a Typical CAD Process on
a CAD/CAM systemDelineation of
geometric model
Definition
translator
Geometric model
Design and
Analysis algorithms
Drafting and
detailing
Documentation
To CAM Process
Interface
algorithms
Design changes
-
8/2/2019 Intro Cad 1
21/56
21
CAD Tools Required to Support the Design Process
Design phase Required CAD tools
Design conceptualization Geometric modeling techniques;Graphics aids; manipulations; and
visualization
Design modeling and simulation Same as above; animation; assemblies;
special modeling packages.
Design analysis Analysis packages; customized
programs and packages.
Design optimization Customized applications; structural
optimization.
Design evaluation Dimensioning; tolerances; BOM; NC.
Design communication and
documentation
Drafting and detailing
-
8/2/2019 Intro Cad 1
22/56
22
Implementation of a Typical CAM Process on
a CAD/CAM systemGeometric model
Interfacealgorithms
Process planning
Inspection
Assembly
Packaging
To shipping and marketing
NC programs
-
8/2/2019 Intro Cad 1
23/56
23
Manufacturing phase Required CAM tools
Process planning CAPP techniques; cost
analysis; material and
tooling specification.
Part programming NC programming
Inspection CAQ; and Inspection
software
Assembly Robotics simulation and
programming
CAM Tools Required to Support the Design Process
-
8/2/2019 Intro Cad 1
24/56
24
Definitions of CAD Tools Based on Their
Constituents
Computer
graphics
concepts
Design toolsGeometric
modeling
CAD
tools
-
8/2/2019 Intro Cad 1
25/56
25
Definition of CAD Tools Based on Their Implementation
in a Design Environment
Design tools + Computer
Hardware
(control unit; display
terminals;I/O devices
Software (graphics;modeling; applications
programs
= CAD tools
-
8/2/2019 Intro Cad 1
26/56
26
Definitions of CAM Tools Based on Their
Constituents
Networking
concepts
Mfg toolsCAD
CAM
tools
-
8/2/2019 Intro Cad 1
27/56
27
Definition of CAM Tools Based on Their Implementation
in a Manufacturing Environment
Mfg tools + Computer
Hardware
(control unit; display
terminals;
I/O devices
Software (CAD; NC;
MRP; CAPP)= CAM tools
Networking
-
8/2/2019 Intro Cad 1
28/56
28
Definitions of CAD/CAM Tools Based on
Their Constituents
Mfg tools
Networking
Design tools
Geometric
modeling
Computer
graphics
concepts
CAD/CAM
tools
-
8/2/2019 Intro Cad 1
29/56
29
Definition of CAD/CAM Tools Based on Their
Implementation in an Engineering Environment
Design and
Mfg tools
Hardware
Software = CAD/CAM tools
Networking
+ Computer
ypical Utilization of CAD/CAM Systems in an Industrial Environme
-
8/2/2019 Intro Cad 1
30/56
30
Geometric modeling
of conceptual design
Is design evaluation
Possible with available
Standard software?
Design testing
And evaluation
Is final design
Applicable?
Drafting
Documentation
Process planning
Are there
manufacturing
discrepancies in CAD
databases?
NC
programming
Machining
Inspection
Assembly
Develop customized
programs and
packages
No
Yes
Yes
Yes
Geometric modeling and graphics package
Design
package
Programming
package
No
No
CAPP package
NC
package
Inspection
And Robotics
package
ypical Utilization of CAD/CAM Systems in an Industrial Environme
-
8/2/2019 Intro Cad 1
31/56
31
Automation and CAD/CAM
Automation can be defined as the
technology concerned with the application
of complex mechanical, electronic, andcomputer-based systems in the operation
and control ofmanufacturing systems.
TT pes of Man fact ring S stems
-
8/2/2019 Intro Cad 1
32/56
32
TTypes of Manufacturing Systems
1. Continuous-flow processes. Continuous dedicated production of
large amount of bulk product. Continuous manufacturing is
represented by chemicals, plastics, petroleum, and food industries.
2. Mass production of discrete products. Dedicated production of
large quantities of one product (with perhaps limited model
variations). Examples include automobiles, appliances and engine
blocks.3. Batch production. Production of medium lot sizes of the same
product. The lot may be produced once or repeated periodically.
Examples: books, clothing and certain industrial machinery.
4. Job-shop production. Production of low quantities, often one of akind, of specialized products. The products are often customized
and technologically complex. Examples: prototypes, aircraft,
machine tools and other equipment.
-
8/2/2019 Intro Cad 1
33/56
33
Productionquantity
Continuous-
flow
production Mass
production
Batchproduction
Job shop
production
Product variety
-
8/2/2019 Intro Cad 1
34/56
34
Category Automation achievements
Continuous-flow process Flow process from beginning to end
Sensors technology available to measureimportant process variables
Use of sophisticated control and optimization
strategies
Fully computer automated lines
Mass production of discrete products Automated transfer machines
Dial indexing machines
Partially and fully automated assembly lines
Industrial robots for spot welding, part handling,
machine loading, spray painting, etc.
Automated material handling systems
Computer production monitoring
Batch production Numerical control (NC), direct numerical
control (DNC), computer numerical control(CNC).
Adaptive control machining
Robots for arc welding, parts handling, etc.
CIM systems.
Job shop production Numerical control, computer numerical control
-
8/2/2019 Intro Cad 1
35/56
35
Most of the automated production systems implemented today
make use of computers. CAD/CAM in addition to its particular
emphasis on the use of computer technology, is also
distinguished by the fact that it includes not only the
manufacturing operations but also the design and planning
functions that precede manufacturing.
To emphasize the differences in scope between automation and
CAD/CAM, consider the following mathematical model:
Computer Technology in Automation
-
8/2/2019 Intro Cad 1
36/56
36
321 TBTBQTTTlc
BQ
T
Q
TT
Tlc
321cyclelifeitsduring
productofuniteachonspenttimeaverageThe
.productdifferenteachforonceedaccomplisharethatactivities
othertheallforandproductthedesigningforrequiredtimeThe3 T
.productionofbatcheachforupsettingandplanningwithassociatedtimeThe2 T
cycle.lifeproductt thethroughouproducedbatchesofnumberTheB
product.ofunitoneproducetorequiredtimeThe1 T
batch.eachinproducedunitsofnumberTheQ
cyclelifeproducttheduringtimetotalclTT
-
8/2/2019 Intro Cad 1
37/56
37
Automation technology is concerned with reducing
the with emphasis on the unit production
time
CAD/CAM concerned with reducing all three
terms, but is perhaps focused on terms.The emphasis in CAD/CAM includes the design
and planning function of the product life cycle.
1T
32 &TT
The most important term in mass production
and batch production
become very important in job shopmanufacturing.
1T
32 &TT
21
&TT
-
8/2/2019 Intro Cad 1
38/56
38
Advantages of CAD/CAM
systems Greater flexibility.
Reduced lead times.
Reduced inventories. Increased Productivity.
Improved customerservice.
Improved quality. Improved communications
with suppliers.
Better product design.
Greater manufacturingcontrol.
Supported integration.
Reduced costs.
Increased utilization.
Reduction of machinetools.
Less floor space.
-
8/2/2019 Intro Cad 1
39/56
Computer-aided manufacturing(CAM) is
defined as the effective use computer
technology in manufacturing planning andcontrol .
CAM is most closely associated with
functions in manufacturing engineering ,such as process and production planning ,
machining , scheduling, management,
39
-
8/2/2019 Intro Cad 1
40/56
quality control, and numerical control (NC)
part programming.
Computer-aided design and computer-aidedmanufacturing are often combined
CAD/CAM systems
40
-
8/2/2019 Intro Cad 1
41/56
This combination allows the transfer of
information from the design into the stage
of planning for the manufacturing of aproduct, without the need to reenter the data
on part geometry manually.
The database developed during CAD isstored; then it is processed further, by
41
-
8/2/2019 Intro Cad 1
42/56
CAM, into the necessary data and
instructions for operating and controlling
production machinery, material- handlingequipment, and automated testing and
inspection for product quality
42
-
8/2/2019 Intro Cad 1
43/56
Rationale for CAD/CAM
The rationale for CAD/CAM is similar to
that used to justify any technology-based
improvement in manufacturing. It grows ourof a need to continually improve
productivity, quality and competitiveness.
43
-
8/2/2019 Intro Cad 1
44/56
There are also other reasons why a company
might make conversion from manual processes
to CAD/CAM: Increased productivity and Better quality
Better communication
Common database with manufacturing
Reduced prototype construction casts
Faster response to customers44
-
8/2/2019 Intro Cad 1
45/56
Applications of CAD/CAM
The emergence of CAD/CAM has had a
major impact on manufacturing, by
standardizing product development and byreducing design effort, tryout, and prototype
work; it has made possible significantly
reduced costs and improved productivity.
45
-
8/2/2019 Intro Cad 1
46/56
Some typical applications of CAD/CAM are
as follows:
Programming for NC, CNC, and industrialrobots;
Design of dies and molds for casting, in
which, for example, shrinkage
46
-
8/2/2019 Intro Cad 1
47/56
CAD Platform In general, we can run CAD software on three
different CAD platforms: Mainframe,
Workstation, and PC. When the CAD
programs first became available, they couldonly be run on a mainframe computer.
However, as the PCs have become faster and
cheaper, almost all the CAD vendors haveintroduced a version of their CAD software
that will effectively run on a Pentium or
higher computer.47
-
8/2/2019 Intro Cad 1
48/56
48
-
8/2/2019 Intro Cad 1
49/56
CAD Evaluation Criteria In the current CAD market, ProE and
AutoCAD are arguably the most dominating
CAD software. AutoCAD is basically a 2-D
program, with some capability to create 3-Dmodels, where as, ProE is a truly 3-D CAD
package.
Following is a brief description of thegeneral criteria for evaluating a CAD
package.49
-
8/2/2019 Intro Cad 1
50/56
Hardware: Most desirable features in a good
hardware are:
Open architecture
High speed, large storage
Compact size
Inexpensive components
Inexpensive upgrading
50
-
8/2/2019 Intro Cad 1
51/56
Software: In general, the most comprehensive
software are written to satisfy almost all the
modeling needs of a modeler, consequently,the software tend to be very complex and hard
to learn.
To create a simple model, we go throughseveral unnecessary steps, and lack the
intuitiveness of a simple, straightforward
program. 51
-
8/2/2019 Intro Cad 1
52/56
There are several other factors that we
should consider when evaluating software.
Following is a brief description of thesefactors.
Operating System: Unix or Windows/NT.
PCs in general use Microsoft Windows,where as, operating system for Workstations
is Unix.52
-
8/2/2019 Intro Cad 1
53/56
User Interface: Most popular CAD software
have menu driven commands, which is
preferable to the old system of non-menudriven, where user interface was completely
by responding to software commands.
Documentation and Support: Learning asoftware can be very difficult if the software
lacks good documentation.
53
-
8/2/2019 Intro Cad 1
54/56
Maintenance: Cost of the hardware and
software upgrades can significantly impact
the small and medium size companiesdecision to choose one software over the
others.
Modeling Capabilities: In, general, a CADsoftware can be classified as either a 2-D or
a 3-D program.54
-
8/2/2019 Intro Cad 1
55/56
Ease of Modeling: As a rule-of-thumb, a
general, all-purpose type CAD software is
much more complex and difficult to learnthan a special purpose CAD package.
Interface with other CAD Packages and
Data Transferability: A CAD package isused to create models that will be used for
analysis, manufacturing, or some other
applications. 55
-
8/2/2019 Intro Cad 1
56/56
Design Documentation: Besides creating a
model, the software should be capable of
creating drawings, assemblies,dimensioning, various views (isometric,
orthogonal, etc.), labels and attributes, etc.
56