ME110- Introduction to CAD Craig R. Ronald Gavett 244

Course Format PTC Creo Industry recognized leader in mechanical design software. Focus on solid modeling, detailing and assemblies. MicroStation- Ranked number 1 by PC magazine etc. How many have had drawing? How many CAD? Computer experience? Half the number of homeworks (5), half the number of tests (2) Review outline. Flexible because of new format. New mailbox thing. Textbook useful for review, but is not needed for homework or tests Explain benefits of helping each other.

Design Examples Astin Martin KTM Motorcycles Artificial Heart

Design Examples Guitars Komatsu Construction

About the Instructor MS Mechanical Engineering U of R 1990 Taught ME110 since 1987 Used PTC Creo 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 Link is on Blackboard The web site will be kept up to date http://www.me.rochester.edu/courses/ME110 Link is on Blackboard 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: learn.rochester.edu Assignments Grades

Course Outline Phone numbers 259-6119 Cell(‘til 10PM) E-mail: ronald@me.rochester.edu

Saving Work for Course Flash Drive you will need to have a USB flash drive by next lecture. All HW and test files must be saved Must be able to show the original files in case of grading disputes.

Academic Honesty All assignments and activities associated with this course must be performed in accordance with the University of Rochester's Academic Honesty Policy.  Suspected violations will be pursued vigorously following the College’s procedures for suspected cases of academic dishonesty. Collaboration on homework is encouraged Each student must create and submit their own file while logged onto their own NetID Sharing files, data, or accounts on homework or tests is prohibited.

Conclusion SAVE YOUR WORK DON’T CHEAT

Six View Orthographic Projection Multiview Projection Adjacent views are reciprocal- Always lined up Show Height, Width, Depth Front view- Shows operating position

Three views are usually sufficient Minimum views necessary to describe the part

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 Plastic printing from a spool of material

3D Printing Inkjet printer glues together layers of 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