ME110- Introduction to CAD Craig R. Ronald Hylan 303

Course Format l Pro/ENGINEER »Industry recognized leader in mechanical design software. l 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 l MS Mechanical Engineering U of R 1990 l Taught ME110 since 1987 l Used Pro/ENGINEER since 1997

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

Web Site l The web site will be kept up to date l Check frequently! You are responsible for knowing the information on the site.

Blackboard l Log on at: l Assignments l lists l Grades

Course Outline l Phone numbers Work Cell (‘til 10PM) l

Course Outline cont’d l Memory Stick –you will need to have a USB memory stick by next lecture

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

Six View Orthographic Projection

Three views are usually sufficient

l Choice of views –least hidden lines –clarity –only necessary views

Precedence of Lines l Visible l Hidden l Center

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

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

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

Solid Modeling l 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? l Intelligent modeling- modeler can understand concept like through, through until, etc.

Accurate Detailing –Hidden lines –Section views –Auxiliary views

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

Interference checking

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

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

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

Demo

Types of Solid Modeling l 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 l 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 UnionDifferenceIntersection

CSG- Constructive Solid Geometry