1. ERT 243/3 Computer Aided Design For Biosystem Engineering (CAD) Prepared By: Siti Kamariah Md Sa’at Email: sitikamariah@unimap.edu.my Phone:012-7549710

2.  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

3. Assessment and Grading  PROJECT/ASSIGNMENT- 40%  TEST 1- 10%  TEST 2- 10%  FINAL TEST- 40%

4.  Engineering drawing  Computer Aided Design (CAD)  Definition  Design Process  Contribution CAD to Design  History  Design Format  Software  Advantage  Capability  Limitation  Basic information include in drawing

5.  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. What is engineering drawing?

6.  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. A picture is worth a thousand words

7.  Giving all of the information needed to make the product and being accurate in that information is the main goal.  Engineers are very picky about their drawings and must pay attention to detail.

8.  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. Computer software Geometric Modelling CAD Tools in design process The integration of computer software and geometric model to serve the design process

10.  Problem definition: design starts with problems  Design specification: eg. Ergonomic (one person handling), load etc  Literature work: search internally and externally (patent, field study etc)  Concept development: Development of the concept  Final concept selection: Select the final concept to develop  Detail design: Detailing the design, DFA can be applied here  Prototyping: Physical model or virtual object  Documentation: Engineering drawing and design report

11.  Conceptualization  Geometric modeling, manipulation and visualization  Analysis  Analysis package, FEA, optimization, customized program  Prototyping  Modeling, assemblies, animation  Communication  Engineering drawing, documentation

12.  CAD had its origins in three separate sources  The first source of CAD resulted from attempts to automate the drafting process. These developments were pioneered by the General Motors Research Laboratories in the early 1960s.

13.  The second source of CAD was in the testing of designs by simulation. The use of computer modeling to test products was pioneered by high-tech industries like aerospace and semiconductors.

14.  The third source of CAD development resulted from efforts to facilitate the flow from the design process to the manufacturing process using numerical control (NC) technologies, which enjoyed widespread use in many applications by the mid-1960s.

15.  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 application: car and aerospace companies  1970s: CAD spread widely in other sectors; film, animation, typographic etc

16. Computer graphics Computer aided drawing and drafting Computer aided design

17.  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.

18.  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.

19.  Point  Line Segment  Polygon  Polyhedron  Curved Surface  Solid Object  Etc.

20.  Autodesk, Inc  AutoCAD  Autodesk Civil 3-D  Autodesk Architectural Desktop  SolidWorks Corporation  SolidWorks 3-D Design Software  Graphisoft  ArchiCAD Design/Building Series

22.  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.

23. 1. Increased accuracy 3. Easy to revise 2. Increased drawing speed 4. Availability of drawing libraries Drafting stage 1. Built-in several analysis tools 2. Better presentation (Easy to visualize) - Pan, rotate, animate, shade, texture Design stage

24. CADD Capability 1. Draw 3. Dimension 2. Modify 4. Object snap 5. Layer concept

25. Limitation of CADD (within scope of drawing creation) Good engineering drawings must have the following characteristics. Parts or product information is completely given. Information is clearly presented. Information can be used in manufacturing of part. Always remind yourself that “Good drawing cannot be created by using CADD software alone without understanding the drawing concepts.”

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

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

28. 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!

29. Projected Views

30. A Table Example

31. 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

33. A Dimensioning Example

34.  Standard Code  Lines  Scaling

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

36. Basic Line Types Types of LinesAppearance Name according to application Continuous thick lineVisible line Continuous thin line Dimension line Extension line Leader line Dash thick lineHidden line Chain thin lineCenter line

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

38. Example : Line conventions in engineering drawing

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

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

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

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

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

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

45. 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

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

47.  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) Scaling

48. Drawing Sheet Trimmed paper of a size A0 ~ A4. Standard sheet size (JIS) A4 210 x 297 A3 297 x 420 A2 420 x 594 A1 594 x 841 A0 841 x 1189 A4 A3 A2 A1 A0 (Dimensions in millimeters)

49. Drawing space Drawing space Title block d d c c c Border lines 1. Type X (A0~A4) 2. Type Y (A4 only) Orientation of drawing sheet Title block Sheet size c (mm) d (mm) A4 10 25 A3 10 25 A2 10 25 A1 20 25 A0 20 25

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