ME110- Introduction to CAD

1. ME110- Introduction to CAD Craig R. Ronald Hylan 303

2. Course Format • Pro/ENGINEER • Industry recognized leader in mechanical design software. • Focus on solid modeling, detailing and assemblies.

3. Design Examples X-38 Crew Return Vehicle Barbie Beetle

4. Design Examples Paintball Mask LeMans Race Car Dentist Chair

5. Design Examples Automatic Bus Transmission John Deere Combine

6. About the Instructor • MS Mechanical Engineering U of R 1990 • Taught ME110 since 1987 • Used Pro/ENGINEER since 1997

7. Importance of Course • Only a 2 credit course but... • Teaches the language of engineering • Skill that is most likely to help job search

8. Web Site • http://www.me.rochester.edu/courses/ME110 • The web site will be kept up to date • Check frequently! You are responsible for knowing the information on the site.

9. Blackboard • Log on at: http://my.rochester.edu/ • Assignments • Email lists • Grades

10. Course Outline • Phone numbers 256-6623 Work 425-4661 Home (‘til 10PM) • E-mail: c.ronald@rochester.edu

11. Course Outline cont’d • Memory Stick • you will need to have a USB memory stick by next lecture

12. Grading • 6 Homework worth 8 points each, Lowest grade is dropped! • 1 midterm test worth 30 points, no curving. • Second exam worth 30 points on last day of class.

13. Six View Orthographic Projection

14. Three views are usually sufficient

15. Choice of views • least hidden lines • clarity • only necessary views

17. Precedence of Lines • Visible • Hidden • Center

19. Meaning of lines • intersection of 2 surfaces • edge view of a surface • contour of a curved surface

21. Section Views • Use section views to eliminate hidden lines. • All visible lines behind plane shown. • Hidden lines are rarely shown.

22. Types of CAD systems • Wireframe- modeling the curves of the part • Surface modeling- Model the surfaces of the part, but without knowledge of material. • Solid modeling- full solid representation • Parametric Modeling- dimension driven solid modeling.

23. Solid Modeling • What is a solid model? • A three dimensional representation of geometry that includes the shape definition of the geometry as well as a definition of inside and outside.

24. Why use a solid modeler? • Intelligent modeling- modeler can understand concept like through, through until, etc.

25. Accurate Detailing • Hidden lines • Section views • Auxiliary views

26. Manufacturing- • Tool paths may be made directly from the model.

28. Interference checking

29. Finite Element Analysis • Ability to do Deflection and stress analysis on complex parts/assemblies. • Complex problems are discritized into simple shapes.

31. Rapid Prototyping • Stereo Lithography • Light setting polymer is built up layer by layer with a laser.

32. 3D Printing • Inkjet printer glues together layers of Plastic or Stainless steel powder. • Sintering binds the powder.

33. Demo

34. Types of Solid Modeling • B-REP– Boundary representation • The solid is defined by the surfaces bounding the volume as well as inside and outside definition. (outward unit normal)

35. Types of Solid Modeling • CSG- Constructive Solid Geometry • Primitive solid shapes joined together with Boolean operators define the solid. The model is stored with a tree structure. • Boolean operators are three-dimensional set operators (union, difference, and intersection).

36. Set Theory Union Difference Intersection

37. CSG- Constructive Solid Geometry