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Prototyping

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					Prototyping
Chapter Table of Contents
1.    Introduction
2.    Development Processes and Organizations
3.    Product Planning
4.    Identifying Customer Needs
5.    Product Specifications
6.    Concept Generation
7.    Concept Selection
8.    Concept Testing
9.    Product Architecture
10.   Industrial Design
11.   Design for Manufacturing
12.   Prototyping
13.   Robust Design
14.   Patents and Intellectual Property
15.   Product Development Economics
16.   Managing Projects
    Product Development Process

               Concept     System-Level   Detail     Testing and     Production
Planning     Development      Design      Design     Refinement       Ramp-Up




           Prototyping is done throughout the development process.
             Concept Development Process
 Mission                                                                                                            Development
Statement    Identify     Establish      Generate        Select           Test           Set             Plan          Plan
            Customer       Target         Product       Product          Product         Final        Downstream
              Needs     Specifications   Concepts      Concept(s)       Concept(s)   Specifications   Development


                                                Perform Economic Analysis

                                             Benchmark Competitive Products

                                           Build and Test Models and Prototypes
     Prototyping Example:
Apple PowerBook Duo Trackball
   Four Uses of Prototypes
• Learning
   – answering questions about performance or
     feasibility
   – e.g., proof-of-concept model
• Communication
   – demonstration of product for feedback
   – e.g., 3D physical models of style or function
• Integration
   – combination of sub-systems into system model
   – e.g., alpha or beta test models
• Milestones
   – goal for development team’s schedule
   – e.g., first testable hardware
      Types of Prototypes
                                   Physical

   ball                                    alpha     beta
 support                                 prototype prototype
                                                                 final
prototype                                                      product




                                    trackball mechanism
                                       linked to circuit
Focused                                   simulation     Comprehensive



                    simulation
                    of trackball
                      circuits                   not
                                              generally
                                               feasible


         equations
        modeling ball
         supports                  Analytical
Physical vs. Analytical Prototypes
        Physical Prototypes             Analytical Prototypes
•   Tangible approximation of   •   Mathematical model of the
    the product.                    product.
•   May exhibit unmodeled       •   Can only exhibit behavior
    behavior.                       arising from explicitly
•   Some behavior may be an         modeled phenomena.
    artifact of the                 (However, behavior is not
    approximation.                  always anticipated.
•   Often best for              •   Some behavior may be an
    communication.                  artifact of the analytical
                                    method.
                                •   Often allow more
                                    experimental freedom than
                                    physical models.
Focused vs. Comprehensive Prototypes

   Focused Prototypes      Comprehensive Prototypes
• Implement one or a few   • Implement many or all
  attributes of the          attributes of the product.
  product.                 • Offer opportunities for
• Answer specific            rigorous testing.
  questions about the      • Often best for milestones
  product design.            and integration.
• Generally several are
  required.
                                  Comprehensive Prototypes
                                    Many comprehensive           Some comprehensive
                                    prototypes are built.     prototypes build (and sold?).
                           High
Technical or Market Risk




                                   One prototype may be        Few or no comprehensive
                                    used for verification.       prototypes are built.
                           Low




                                              Low                     High
                                            Cost of Comprehensive Prototype
         Prototyping Strategy
•   Use prototypes to reduce uncertainty.
•   Make models with a defined purpose.
•   Consider multiple forms of prototypes.
•   Choose the timing of prototype cycles.
    –Many early models are used to validate
     concepts.
    –Relatively few comprehensive models are
     necessary to test integration.
• Plan time to learn from prototype cycles.
    –Avoid the “hardware swamp”.
  Rapid Prototyping Methods
• Most of these methods are additive,
  rather than subtractive, processes.
• Build parts in layers based on CAD
  model.
• SLA=Stereolithogrpahy Apparatus
• SLS=Selective Laser Sintering
• 3D Printing
• LOM=Laminated Object Manufacturing
• Others every year...
        Virtual Prototyping
• 3D CAD models enable many kinds of
  analysis:
  – Fit and assembly
  – Manufacturability
  – Form and style
  – Kinematics
  – Finite element analysis (stress, thermal)
  – Crash testing
  – more every year...
BMW Virtual Crash Test




    From: Scientific American, March 1999
 Traditional Prototyping Methods

• CNC machining
• Rubber molding + urethane casting

• Materials: wood, foam, plastics, etc.
• Model making requires special skills.

				
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