ME110 Introduction to CAD

1
ME110- Introduction to CAD

• Craig R. Ronald
• Harkness 114

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 ronald_at_me.rochester.edu

11
Teaching Assistants

• Rob Halm
• rhalm_at_u.rochester.edu
• Joni Mici 
• joni.mici_at_gmail.com 

12
Course Outline contd

• Memory Stick
• you will need to have a USB memory stick by next
  lecture

13
Grading

• 6 Homework worth 8 points each, Lowest grade is
  dropped!
• 1 midterm test worth 30 points, no curving.
• Final exam worth 30 points.

14
Six View Orthographic Projection
15
Three views are usually sufficient
16

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

17
(No Transcript)
18
Precedence of Lines

• Visible
• Hidden
• Center

19
(No Transcript)
20

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

21
(No Transcript)
22
Section Views

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

23
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.

24
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.

25
Why use a solid modeler?

• Intelligent modeling- modeler can understand
  concept like through, through until, etc.

26
Accurate Detailing

• Hidden lines
• Section views
• Auxiliary views

27
Manufacturing-

• Tool paths may be made directly from the model.

28
(No Transcript)
29
Interference checking
30
Finite Element Analysis

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

31
(No Transcript)
32
Rapid Prototyping

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

33
3D Printing

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

34
Demo
35
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)

36
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).

37
Set Theory
Union
Difference
Intersection
38
CSG- Constructive Solid Geometry