Shad Valley MUN Introduction to Product Design and Development Lecture 4: Part 2 Prototyping Dr. Leonard M. Lye, PEng, FCSCE Professor of Civil Engineering Program Director, MUN Shad Shad Valley MUN

Introduction Prototype = an approximation of the product along one or more dimensions of interest. Alpha prototypes: Used to assess whether product works as intended. Similar in material and geometry as production version, but made differently. E.g. machined instead of molded. Beta prototype: Used to assess reliability and to identify remaining bugs in the product. Given to customers for testing in the use environment. Parts are usually made with the actual production process and supplied by intended parts suppliers. Assembled by team rather than the manufacturer. Shad Valley MUN

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 Shad Valley MUN

Physical vs. Analytical Prototypes Physical Prototypes Tangible approximation of the product. May exhibit unmodelled behavior. Some behavior may be an artifact of the approximation. Often best for communication. Analytical Prototypes Mathematical model of the product. Can only exhibit behavior arising from explicitly modelled phenomena. (However, behavior is not always anticipated. Some behavior may be an artifact of the analytical method. Often allow more experimental freedom than physical models. Shad Valley MUN

Focused vs. Comprehensive Prototypes Focused Prototypes Implement one or a few attributes of the product. Answer specific questions about the product design. Generally several are required. Comprehensive Prototypes Implement many or all attributes of the product. Offer opportunities for rigorous testing. Often best for milestones and integration. Shad Valley MUN

Comprehensive Prototypes Many comprehensive prototypes are built. Some comprehensive prototypes build (and sold?). High Technical or Market Risk One prototype may be used for verification. Few or no comprehensive prototypes are built. Low Low High Cost of Comprehensive Prototype Shad Valley MUN

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”. Shad Valley MUN

Rapid Prototyping Methods Most of these methods are additive, rather than subtractive, processes. Build parts in layers based on CAD model. SLA=Stereolithography Apparatus FDM=Fused Deposition Modelling 3D Printing LOM=Laminated Object Manufacturing Others every year... Shad Valley MUN

3-D Printing Similar to a photocopier except that it prints in 3-D. Check out http://www.fabathome.org Build it yourself 3-D printing device And http://www.cc.utah.edu/~asn8200/rapid.html Shad Valley MUN

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... Shad Valley MUN

From: Scientific American, March 1999 BMW Virtual Crash Test From: Scientific American, March 1999 Shad Valley MUN

Traditional Prototyping Methods CNC machining Rubber molding + urethane casting Materials: wood, foam, plastics, etc. Model making requires special skills! Shad Valley MUN

Planning for Prototypes – 4 steps Step 1: Define the purpose of the prototype. What is the prototype for? Is it for learning, communication, integration, or milestone? Step 2: Establish Level of Approximation. Is an analytical prototype good enough or a physical prototype necessary? Should it “works like” or just “looks like”? Step 3: Outline an Experimental Plan Decide on what measurements have to be taken. What combinations of configurations need to be tested? Test conditions? Step 4: Create a Schedule for Procurement, Construction, and Testing. Prototyping is a sub-project within the overall product development project. What parts need to be ordered, assembled? When must it be completed? How much time for testing? Shad Valley MUN

Summary Prototypes are used for learning, communication, integration, and milestones. Physical prototypes are best for communication, and comprehensive prototypes are best for integration and milestones. Analytical prototypes are generally more flexible than physical prototypes. Physical prototypes are required to detect unanticipated phenomena. Shad Valley MUN

Summary (Continue) 3-D computer modelling and free-form fabrication technologies have reduced the relative cost and time required to create prototypes. A 4-step method for planning prototype is: Define the purpose of the prototype Establish the level of approximation of the prototype. Outline an experimental plan Create a schedule for procurement, construction, and testing. Shad Valley MUN

Thought Question Some companies have reportedly abandoned the practice of doing a customer test with the early prototypes of their products, preferring instead to go directly and quickly to market in order to observe the actual customer response. For what types of products and markets might this practice make sense? Shad Valley MUN