1. PRESENTATION ON COMPUTER
AIDED DESIGN
INDUSTRIAL ENGINEERING AND
MANAGEMENT

2. GROUP MEMBERS:
 MUHAMMAD HASNAIN SIDDIQI
(D-13-IN-07)
 MUHAMMAD AHSAN
(D-13-IN-10)
 AJMAL QURESHI
(D-13-IN-28)
IN THE NAME OF ALLAH THE MOST
MERCIFUL AND BENEFICIAL

3. TABLE OF CONTENTS
Engineering Drawing
Engineering Drawings: Common Features
Computer Aided Design.
History of CAD.
Future of CAD.
Rapid Prototype
o HISTORY
o THE BASIC PROCESS
o RP-TECHNOLOGIES
o GENERAL ADVANTAGES OF RP

4. ENGINEERING DRAWING
An engineering drawing, a type of technical
drawing , is used to fully and clearly define
requirements for engineered items.
More than just the drawing of pictures, it is also
a language- a graphical language that
communicates ideas and information from one
mind to another. Most especially, it communicates
all needed information from the engineer
who designed a part to the workers who
will make it.

5. Engineering Drawings: Common
FeaturesDrawings convey the following critical information:
 Geometry – the shape of the object; represented as views; how
the object will look when it is viewed from various angles, such
as front, top, side, etc.
 Dimensions – the size of the object is captured in accepted
units.
 Tolerance– the allowable variations for each dimension.
 Material – represents what the item is made of.
 Finish – specifies the surface quality of the item, functional or
cosmetic. For example, a mass-marketed product usually
requires a much higher surface quality than, say, a component
that goes inside industrial machinery.

6. Why we need engineering drawing?
Purpose of Engineering Drawings
To appreciate the need for technical drawings, one must
understand the design process. The design process is an
orderly, systematic procedure used in accomplishing a
needed design. Any product that is to be manufactured,
fabricated, assembled, constructed, built, or subjected to
any other types of conversion process must first be
designed. For example, a house must be designed before
it can be built.

8. Computer-aided design (CAD) is the
use of computer systems to assist in the
creation, modification, analysis, or
optimization of a design. CAD software is
used to increase the productivity of the
designer, improve the quality of design,
improve communications through
documentation, and to create a database
for manufacturing. CAD output is often in
the form of electronic files for print,
machining, or other manufacturing
operations.
Example: 3D CAD model
Example: 2D CAD drawing

9. H
I
S
T
O
R
Y
O
F
C
A
D
The work of two people in particular—Patrick Hanratty and
Ivan Sutherland—who are largely credited with setting the
stage for what we know today as CAD.
 Hanratty is widely credited as “the Father of CADD/CAM.” In 1957,
while working at GE, he developed PRONTO (Program for Numerical
Tooling Operations).
 Sutherland presented his Ph.D. thesis at MIT titled “Sketchpad, A
Man-Machine Graphical Communication System.” Among its features,
the first graphical user interface, using a light pen to manipulate
objects displayed on a CRT.

10.  The 1960s number of companies were founded to
commercialize their fledgling CAD programs,
including SDRC, Evans & Sutherland, Applicon,
Computer vision, and M&S Computing.
 By the 1970s, research had moved from 2D to 3D.
Major milestones included the work of Ken
Versprille, whose invention of NURBS for his Ph.D.
thesis formed the basis of modern 3D curve and
surface modeling, and the development by Alan
Grayer, Charles Lang, and Ian Braid of the PADL
(Part and Assembly Description Language) solid
modeler.
 With the emergence of UNIX workstations in the
early ’80s, commercial CAD systems like CATIA and
others began showing up in aerospace,
automotive, and other industries. The following
year, a group of programmers formed Autodesk,
and in 1983 released AutoCAD, the first significant
CAD program for the IBM PC.
H
I
S
TO
R
Y
O
F
C
AD

11. CAD Today, CAD Tomorrow
The modern CAD era has been marked by improvements in modeling,
incorporation of analysis, and management of the products we create, from
conception and engineering to manufacturing, sales, and maintenance (what has
become known as PLM, product lifecycle management).
“Engineers and designers
are being asked to create
more, faster, and with
higher quality,”says Bill McClure, vice president of
product development at Siemens PLM.
With all of this pressure on engineers and designers, what do you see as the
next big evolution in CAD?

13. RAPID PROTOTYPING
The term rapid prototyping (RP) refers to a class of technologies that can
automatically construct physical models from Computer-Aided Design (CAD)
data. Prototyping or model making is one of the important steps to finalize
a product design. It helps in conceptualization of a design. Before the start
of full production a prototype is usually fabricated and tested.
• The main advantage of the system is that almost any shape can be
produced. Time and money savings vary from 50 –90 %compared to
conventional systems.
• Rapid prototyping techniques are often referred to solid free-form
fabrication, computer automated manufacturing or layered
manufacturing.
• The computer model is sliced into thin layers and the part is fabricated
by adding layers on to of each other.

14. HISTORY
 Manual prototyping by a skilled craftsman has been an age-
old practice for many centuries.
 Second phase of prototyping started around mid-1970s, when
a soft prototype modeled by 3D curves and surfaces could be
stressed in virtual environment, simulated and tested with
exact material and other properties.
 Third and the latest trend of prototyping, i.e., Rapid
Prototyping (RP) by layer-by-layer material deposition, started
during early 1980s with the enormous growth in Computer
Aided Design and Manufacturing (CAD/CAM) technologies.

15. THE BASIC PROCESS
CREATING THE 3D CAD MODEL OF THE
DESIGN
CONVERTING THE CAD MODEL INTO
STL FORMAT
SLICING THE STL FILE INTO THIN
LAYERS
CONSTRUCTING THE MODEL ONE
LAYER ATOP ANOTHER
CLEANING AND FINISHING THE
MODEL

16. CAD MODEL CREATION:
• First the object to be build is modeled:
• •using a CAD software package
• •or by using a laser scanner or a Coordinate Measuring Machine
(CMM).
Coordinate Measuring Machine laser scanner

17. CONVERSION TO STL FORMAT
• The standard data interface between CAD
software and the machine is the STL-
format (Stereo lithography).
• An STL-file approximates the shape of a
part using triangular facets. Small facets
produce a high quality surface. Since the
.stl format is universal, this process is
identical for all of the RP build techniques.

18. SLICE THE STL FILE:
http://www.youtube.com/watch?v=80aXU5q2
Kgg.

19. LAYER BY LAYER CONSTRUCTION
The Fourth step is the actual construction of the
part. Using one of several techniques. RP machines
build the model layer by layer. The material´s initial
states are:
 LIQUID
 SOLID or
 POWDER

20. CLEAN AND FINISH
Re-movement of the part from the machine
•Detaching any supports
•After cure(some photo sensitive materials)
•Cleaning and surface treatment
•Possible painting etc.

21. RP-TECHNOLOGIES
1. Stereo lithography
(SLA)
Stereo lithography is the
most widely used RP-
technology. It can produce
highly Accurate and
detailed polymer parts.
SLA was the first RP-
process, introduced in
1988 by 3D Systems Inc.
Abbreviation: SLA
Material type: Liquid(Photopolymer
Materials: Thermoplastics(Elastomers)
Min layer thickness: 0,02mm
Surface finish: Smooth
Build speed: Average
Applications:
Form/fit testing, Functional
testing, Very detailed parts,
Presentation models, Snap fits..

22. FUSED DEPOSITION MODELING
FDM was developed by Stratasys. In this process, a plastic or
wax material is extruded through a nozzle that traces the
part´s cross sectional geometry layer by layer.
Abbreviation: FDM
Material type: Solid(Filaments)
Materials: ABS, Polycarbonate, Polyphenylsulfonite;
Elastomers
Min layer thickness: 0,15mm
Surface finish: Rough
Build speed: Slow
Applications: Form/fit testing, Functional testing, Small
detailed parts, Presentation models…

23. 3D PRINTING
Three Dimensional Printing (3DP)
technology was developed at the
MIT and licensed to several
corporations. Material options are
somewhat limited but are
inexpensive relative to other
additive processes. 3D printing is
quite fast, typically 2 –4
layers/minute. However, the
accuracy, surface finish, and part
strength are not as good as some
other additive processes. At the
end the part is infiltrated with a
sealant to improve strength and
surface finish.
Abbreviation: 3D PRINTING
Material type Powder
Materials:
Ferrous metals
Bronze; Elastomers
Min layer thickness: 0,05mm
Surface finish: Rough
Build speed: Very Fast
Applications:
Concept models, Limited
functional testing,
Architectural& landscape
models, Consumer goods&
packaging

24. GENERAL ADVANTAGES OF RP
 Almost any shape or geometric feature can be produced.
 Reduction in time and cost (could range 50 –90%. Wohler)
 Errors and flaws can be detected at an early stage.
 RP/RM can be used in different industries and fields of life
(medicine, art and architecture, marketing..)
 Discussions with the customer can start at an early stage.
 Assemblies can be made directly in one go.
 Material waste is reduced.
 No tooling is necessary.
 The designers and the machinery can be in separate places.

25. SPECIAL THANKS
SIR AURANGZEB JUNEJO.
THANK YOU FOR YOUR
ATTENTION
PRESENTATION PREPARED BY:
MUHAMMAD HASNAIN SIDDIQI