1. ERT 249 Computer Aided Design (CAD) For Biosystem Engineering
Prepared By:
Samera binti Samsuddin Sah
Phone: /

2. CREATE curve, surfaces and geometric models
Learning Outcomes
APPLY geometric construction techniques to create engineering drawings using CAD.
CREATE completes 2-D and 3-D drawings pertaining to geometric transformations, projections and multiple views.
CREATE curve, surfaces and geometric models
DESIGN and INVESTIGATE the behavior of parts and assemblies under load.

3. Assessment and Grading
EXAMINATION (40%)
TEST 1 = 20%
TEST2 = 20%
COURSEWORK (60%)
QUIZZES/ASSIGNMENTS = 20%
MINI PROJECT = 25%
PROJECT = 15%

4. History 1963 : Modeled in 3D by T.E Johnson.
1962: SKETCHPAD system developed by Ivan Sutherland, MIT (2D graphic).
For the first time, designer can interact with the computer graphically, before computer used for numerical analysis
1963 : Modeled in 3D by T.E Johnson.
Early apllication - car and aerospace companies
1970s : CAD spread widely in other sectors; film, animation, typographic etc

5. Computer aided drawing and drafting
Evolution of CAD
Computer graphics
Computer aided drawing and drafting
Computer aided design

6. Introduction Computer Aided Design (CAD) Engineering Drawing
Definition
Design Process
Contribution CAD to Design
History
Design Format
Software
Advantage
Capability
Limitation
Basic information include in drawing

7. Engineering Drawing
An engineering drawing, a type of technical drawing, is created within the technical drawing discipline, and used to fully and clearly define requirements for engineered items.
The main purpose of engineering drawings is to communicate to other engineers, machinists, etc.
A formal and precise way of information about the shape, size, features and precision of physical objects.
Drawing is the universal language of engineering.
Giving all of the information needed to make the product and being accurate in that information is the main goal. 

8. Computer Aided Design (CAD)
Also known as Computer-aided drafting and design (CADD)
Describe the use of computer program to create design and engineering applications.
The computer process of making engineering drawings and technical documents more closely related to drafting.

9. Tools in design process
Computer Aided Design
CAD
Tools in design process
The integration of computer software and geometric model to serve the design process

10. 5. Final concept selection
Design Process
1. Problem definition
Design starts with problems
2. Design specification
eg. Ergonomic (one person handling), load etc
3. Literature work
Search internally and externally (patent, field study etc)
4. Concept development
Development of the concept
5. Final concept selection
Select the final concept to develop
6. Detail design
Detailing the design, Design for Assembly (DFA) can be applied here
7. Prototyping
Physical model or virtual object
8. Documentation
Engineering drawing and design report

11. Contribution of CAD in design
Conceptualization
Geometric modeling, manipulation and visualization
Analysis
Analysis package, Finite Element Analysis (FEA), optimization, customized program
Prototyping
Modeling, assemblies, animation
Communication
Engineering drawing, documentation

12. Design Formats 3-D Solid Models 2-D Drawings Two-dimensional
Having length and width/height dimensions
View of object appear in flat form
Often dimensioned and contain notes and text describe features and details of the part, map or plan.
Identical to drawing created to manual drafting technique.
3-D Solid Models
Describe both the interior and exterior of a part
Constructed differently depending on the software
Some software allow you to produce basic solid model using tools including solid primitive.

13. 3D Geometric Primitives
Point;
Line Segment;
Polygon;
Polyhedron;
Curved Surface;
Solid Object, etc.

14. CAD Software Product Autodesk, Inc AutoCAD Autodesk Civil 3-D
Autodesk Architectural Desktop
Autodesk Professional Inventor
SolidWorks Corporation
SolidWorks 3-D Design Software
Graphisoft
ArchiCAD Design/Building Series

15. AutoCAD Interface

16. Advantages of CAD
Better work rather than traditional drafting methods that use rulers, squares, and compasses. For example, designs can be altered without erasing and redrawing.
CAD systems also offer “zoom” features whereby a designer can magnify certain elements of a model to facilitate inspection.
Computer models are typically three dimensional and can be rotated on any axis, enabling the designer to gain a fuller sense of the object.
CAD systems also lend themselves to modeling cutaway drawings, in which the internal shape of a part is revealed. 1. 2. 3. 4.

17. Advantages of CAD Design Drafting stage stage Increased accuracy
Increased drawing speed
Easy to revise
Availability of drawing libraries
Design
stage
Built-in several analysis tools
Better presentation (Easy to visualize) Pan, rotate, animate, shade, texture

18. CAD Capability 1. Draw 2. Modify 3. Dimension 4. Object snap
5. Layer concept

19. Limitation of CAD (within scope of drawing creation)
Good engineering drawings must have the following characteristics
3. Parts or product information is completely given
1. Information is clearly presented
2. Information can be used in manufacturing of part

20. Limitation of CAD (within scope of drawing creation)
To create a good engineering drawings YOU MUST do the following tasks yourself.
Apply a proper line weight and style
Select a necessary view
Decide the appropriate place of dimensions
Select an appropriate section techniques (if necessary)

21. Limitation of CAD (within scope of drawing interpretation)
No CADD software can create a pictorial view from an orthographic multiview.
Because they are frequently used technical document.
Therefore, YOU MUST prepare yourself for interpreting (or visualizing) them when you become ENGINEER.

22. Basic Information Included in a Drawing
Projected Views:
Show as many sides as needed for completeness.
Cross Sections:
A view that is good for showing interior features.
Table:
Lower right corner, with material information, part name, designer etc
Dimension:
These are the most important and most complicated part of the drawing. There is more to it than just the numerical values!

23. Projected Views

24. A Table Example

25. There are also Radial, Diameter and Angular Dimensions.
Dimensions tell how far it is from one point on an object to another point. 
The most basic type is called a Linear Dimension because it gives the straight-line distance from one point to another. 
There are also Radial, Diameter and Angular Dimensions.
Dimensions have four basic components:
Dimension Text
Dimension Line and Arrows
Extension Lines
Gap

27. A Dimensioning Example

28. More basic information
Standard Code
Lines
Scaling

29. Standard Code มอก. Country Code Full name Thailand USA ANSI
สำนักงานมาตรฐานผลิตภัณฑ์อุตสาหกรรม
Thailand
ANSI
American National Standard Institute
USA
JIS
Japanese Industrial Standard
Japan BS
British Standard UK AS
Australian Standard
Australia
Deutsches Institut für Normung
DIN
Germany
ISO
International Standards Organization

30. Basic Line Types Name according to application Types of Lines
Appearance
Continuous thick line
Visible line
Continuous thin line
Dimension line
Extension line
Leader line
Dash thick line
Hidden line
Chain thin line
Center line

31. Meaning of Lines
Visible lines represent features that can be seen in the
current view
Hidden lines represent features that can not be seen in the current view
Center line represents symmetry, path of motion, centers of circles, axis of axisymmetrical parts
Dimension and Extension lines indicate the sizes and location of features on a drawing

32. Example : Line conventions in engineering drawing

33. Line Convention Precedence of coincide lines. Hidden line drawing.
Center line drawing.

34. Precedence of Line Order of importance Visible line Hidden line Center

35. Hidden Line Practice
Hidden line should join a visible line, except it extended from the visible line.
Leave
space
Correct
Join
No !

36. Hidden Line Practice
Hidden line should join a visible line, except it extended from the visible line.
Leave
space
Leave
space
Correct
No !

37. Hidden Line Practice
Hidden line should intersect to form L and T corners. L T
Correct
No !

38. Hidden Line Practice
Hidden arcs should start on a center line.

39. Centre Line Practice
In circular view, short dash should cross at the intersections of center line.
For small hole, center line is presented as thin continuous line.
Center line should not extend between views.
Leave space
Leave space

40. Centre Line Practice
Leave the gap when centerline forms a continuation with a visible or hidden line
Center line should always start and end with
long dash.
Leave space
Leave space
Leave space
Leave space

41. Scaling
Scaling is used to depict objects on paper that are either larger or smaller than the paper.
If the object is larger than the paper, then the views of the object are scaled Down
If the object is smaller than the paper, then the views of the object are scaled Up
If the object fits on the paper, then the views are depicted at Full scale  (1:1)

42. Drawing Sheet Trimmed paper of a size A0 ~ A4.
Standard sheet size (JIS)
A x 297
A x 420
A x 594
A x 841
A x 1189 A1 A0
(Dimensions in millimeters)

43. Orientation of drawing sheet
1. Type X (A0~A4)
2. Type Y (A4 only) c d d c
Drawing
space
Border
lines
Drawing space
Title block
Title block c
Sheet size c (mm) d (mm) A A A A A

44. The end…