CS 294-3: RAPID PROTOTYPING

Lecture #1 -- Friday 8/28, 1998.

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Lecture Topics

Introduction to CS294-3

  • Its Place in the Curriculum

    What CS 294-3 Is All About

    This is a PROJECT Course

    Lectures are in support of the projects, to help you get the job done, and show you how to use certain tools.

    You will learn about:

  • Rapid Model Making tecniques (mostly by SFF)
  • Rapid Prototyping tecniques (mostly by NC milling)
  • Making a pilot batch of parts (mostly by injection molding)
  • Languages and interchange formats to describe parts for submission.
  • Every student will design, submit, and evaluate one or more parts.

    Rapid Model Making by SFF

    Most Solid-Free-form Fabrication (SFF) Methods
    use a constructive approach, building the part layer upon thin layer:
  • Stereolithography (SLA)
    - - Laser cross-links molecules in organic liquid.
  • Selective Laser Sintering (SLS)
    - - High-power laser fuses nylon or ceramic powder.
  • Layered Object Manufacturing (LOM)
    - - Layer of paper are glued on top of one another.
  • Fused Deposition Modeling (FDM)
    - - Hot plastic or wax is dispensed from a moving nozzle.
  • 3D Printing
    - - Wax droplets are dispensed through an inkjet printer head.

    Rapid Prototyping by Machining

    In Numerically Controlled (NC) Machining
    material is removed by a cutting operation:
  • Turning
    - - Piece turns on a lathe, cutting tool is stationary.
  • Drilling
    - - Piece is fixed, rotating tool drills cylindrical holes.
  • Milling
    - - Piece is fixed, rotating tool removes pockets of material.
  • CyberCut
    = 3-axis milling + Reference-Free Part Encapsulation (RFPE)
    - - Piece is encapsulated in plastic, which gets replaced after all operations for one access direction have been done.

    Producing a Pilot Series

    A Successful Prototype may be followed by a series of many parts for product trial:
  • Casting
    - - make a master (e.g., wood -- wax);
    - - take a negative mold (e.g., sand -- plaster);
    - - cast many copies (e.g., cast iron -- bronze);
  • Injection Molding
    - - directly machine the mold (e.g., aluminum);
    - - form parts by injecting hot plastic (reuse mold).

    The CyberCut Project

  • Provide a simple access to part fabrication via the Internet for the occasional, "naive" designer.
  • Modeled after the successful VLSI MOSIS (1980s).
  • Shield designers from tedious or difficult details of the fabrication processes.
  • Help with materials and process selection (MAS).
  • Web-based design tool specifically matched to 3-axis milling (possibly with RFPE).
  • New Solid Interchange Format (SIF) for more general part specification (e.g., --> SFF).
  • Design rulses and corresponding checking tools are under construction.

    Course Administration

  • Default unit value of course is 2 Units;
    - - talk to me if you plan to enroll for a different number of units.
  • If at all possible, take this course S/U or P/NP rather than as an auditor.
  • Fill in and hand in the Background Questionnaire Form.

    Process and Materials Selection

  • The Manufacturing Analysis Service (MAS).
  • The on-line MAS tool (Chuck Smith)
  • Presentation and Demo.

    New Homework Assignment:
    DUE: Friday 9/4/98, -- 9:45am.

    First read the MAS Instructions
    Then, make sure you are on a machine with a Java-enable browser, and
    use the on-line, web-based MAS tool
    Ideally you should set up the Tutorial and the MAS applet side by side,
    so you can refer back to the instructions when necessary.

    The MAS is an interactive exploratory and educational tool. Take your time to go to the associated web pages to look at the process descriptions of processes that you are not familiar with, so that you have a rough idea what they are all about.
    Watch the ranking numbers! If they all drop to zero in response to some choice you made, try other, less constraining choices; find out where the limits are. Think about why these limits come into play.

    Look around you, and pick some plastic or metal part made of uniform material and think about how it may have been made. Use the MAS for a search of the possibilities and compare the result to your experience and to your common-sense understanding of the world. Write down your thoughts and observations.

    Hand in:
    Printouts of the results on two such searches on different parts;
    A 100-200 word critique of the tool and its interface in general;
    A 100-200 word critique of the results produced by the tool.
    Put your name on your hand-ins.

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