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ME110- Introduction to CAD
Craig R. RonaldHylan 303
Course Format
Pro/ENGINEER » Industry recognized leader
in mechanical design software.
Focus on solid modeling, detailing and assemblies.
Design Examples
Barbie Beetle
X-38 Crew Return Vehicle
Design Examples
LeMans Race Car
Paintball Mask
Dentist Chair
Design Examples
John Deere Combine
Automatic Bus Transmission
About the Instructor MS Mechanical Engineering U of R
1990 Taught ME110 since 1987 Used Pro/ENGINEER since 1997
Importance of Course Only a 2 credit course but... Teaches the language of
engineering Skill that is most likely to help job
search
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.
Blackboard Log on at: http://my.rochester.edu/ Assignments Email lists Grades
Course Outline cont’d Memory Stick
– you will need to have a USB memory stick by next lecture
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.
Six View Orthographic Projection
Three views are usually sufficient
Choice of views– least hidden
lines– clarity– only necessary
views
Precedence of Lines
Visible Hidden Center
Meaning of lines– intersection of 2 surfaces– edge view of a surface– contour of a curved surface
Section Views
Use section views to eliminate hidden lines.
All visible lines behind plane shown.
Hidden lines are rarely shown.
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.
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.
Why use a solid modeler? Intelligent modeling- modeler can
understand concept like through, through until, etc.
Accurate Detailing– Hidden lines– Section views– Auxiliary views
Manufacturing- Tool paths may be made directly
from the model.
Interference checking
Finite Element Analysis Ability to do Deflection and stress
analysis on complex parts/assemblies.
Complex problems are discritized into simple shapes.
Rapid Prototyping Stereo Lithography
– Light setting polymer is built up layer by layer with a laser.
3D Printing Inkjet printer glues together layers
of Plastic or Stainless steel powder. Sintering binds the powder.
Demo
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)
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).
Set Theory
Union Difference
Intersection
CSG- Constructive Solid Geometry
