Bruce Mayer, PE Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege.edu

1. Engineering 11 Build & TestProtoTypes Bruce Mayer, PE Licensed Electrical & Mechanical EngineerBMayer@ChabotCollege.edu

2. OutLine  Build & Test Proto’s • Why test? • Form, Fit & Function • Types of tests • Types of Prototypes • Test plans • Summary

3. Need for Physical Testing • We canNOT do EVERYTHING on the COMPUTER • Finished parts do NOT always look the same as designed • Finished parts do NOT always fit together as designed • Finished parts do NOT always work the way they were designed.

4. FORM Tests (easiest) • Some Q’s Answered by FORM Tests • Is the appearance “Dated” or “Stale”? • Is the Product SIZE Acceptable? • E.g., Too: Small, Large, Thick, Thin, Tall, etc. • Is the Part Finish Attractive? • FORM Test Purpose  Will the part/product have an acceptable appearance?

5. FIT Tests (medium effort) • FIT Test Issues • Interference Analysis  Do all the parts in an Assy FIT Together? • Tolerance Analysis  Should any physical Tolerance be Tightened/Loosened? • Assembly Analysis  Can the Assembly Sequence/Process be Improved? • FIT Test Purpose  Will the parts Fit and Assemble?

6. FUNCTION Test (hardest) • Some Q’s Answered by FCN Tests • Does the Product PERFORM as Predicted & Required? • Will the Product Function in Extreme Environments? • e.g. Corrosion, Temperature, Vibration, etc. • Is the Product Function STABLE & REPEATABLE? • Is the Product SERVICEABLE?

7. FUNCTION Test (hardest) • Some Q’s Answered by FCN Tests • Is the Product RELIABLE/DURABLE? • Is the Product REPAIRABLE? • Is the Product SAFE to use? • Does the Product CONFORM to Codes and/or Standards? • Is the Product ERGONOMIC? • Develop Operation & Maintenance Tools and Procedures

8. FUNCTION Test (hardest) • FUNCTION Test Purpose  Determine if the Product has a Realistic Chance of Ultimately Being Saleable? • ProtoType Function Testing is the FINAL Go/No-Go Decision point prior to the commitment of Major-$ for construction of the Production Operation

9. Phase-A Tests: Types & Timing Formulation “Product Concept” tests validate product / appearance “Proof of Concept” tests validate physical principles Concept Design

10. Phase-B Tests: Types & Timing Configuration Design “Virtual prototype” tests solid modeling CAD “Alpha prototype” tests actual geometry & materials but may not use actual mfg. processes Parametric Design

11. Phase-C Tests: Types & Timing “Beta prototype” tests parts made with planned mfg. processes volunteer customers / panel actual operating conditions, environment DetailDesign “Preproduction prototype” tests parts made with final mat’s & processes independent labs: UL, CPSC, NHTSA Manufacture

12. Product concept Proof of concept Virtual (Computer) prototype Alpha prototype Beta prototype Gamma PreProduction prototype Testing Sequence LESS Expensive MORE Expensive Physical & VirtualProtoTypes Need PHYSICAL Prototype

13. Physical ProtoTypes • Form & Fit ProtoType ≡ a replica or model of the part showing principal geometric features • Prototypes differ in: • Scale  Reduced, Full, Expanded • Fabrication Process  Same as mfg, Similar, Different • Material  Same as final, Different, Similar • Kinds of Prototypes: Traditional, Rapid

14. Traditional ProtoTypes • Clay models of new auto body for appearance testing, • Wood models of heavy equipment patterns for metal castings, • Manually machined metal airplane wings for function testing in a wind tunnel, • Reduced-scale balsa-wood or foam models of large facilities, to examine equipment layout.

15. Traditional Proto DisAdvantages • Uses tools and fabrication methods that are labor intensive. • Often require significant mechanical or artistic skills. • Take a long time to fabricate an original. • Revisions may require complete rebuilding of part • Costly for duplicates. • May not facilitate tooling design and construction

16. Rapid ProtoTyping • Rapid Prototyping (RP) ≡a group of techniques used to quickly fabricate a scale model of a part or assembly using three-dimensional computer aided design (CAD) data.

17. Rapid ProtoTyping Methods • NC/CNC Machining • Selective Laser Apparatus • Fused Deposition Modeling • 3-D Ink Jet • Laminated Object Manufacturing • Selective Laser sintering • Service Bureaus

18. CNC ProtoTyping (Subtractive) WorkStation Solid Modeling CAD software Saved Part Solid model file => *.PRT NC code generation NC Machine instruction code file NC/CNC Machine e.g. mill, lathe Fabricated Prototype

19. Numerical Control Machining • Can Do ON CAMPUS • NC  MTT71A • CNC  MTT81A • CAD files are converted to NC–machine instruction codes for automatic machining • Part can be made of metal • Dimensions have excellent tolerances • Multiple copies of parts can be made easily • Good for Form, Fit, Function Prototypes

20. CNC Part Example • AutoMobile WaterPump Pulley

21. RP ProtoTyping (Additive) Workstation Saved Part Solid model file => *.PRT Solid Modeling CAD software Faceted Model file => *.STL Rapid Prototyper Slicing Program RP Machine instruction code file RP Machine Fabricated Prototype

22. StereoLithoGraphy App (SLA) projection mirror (xy-axes) laser elevator (z-axis) object being prototyped PhotoPolymer (liquid resin) Solidified lamina tank

23. 3-D Systems SLA 7000 (Courtesy of 3D Systems)

24. SLA Example: Jaguar manifold (Courtesy of 3D Systems)

25. Stereo Lithography Apparatus • SLA Parts exhibit superior finishes • SLA polymeric prototypes are weaker than NC/CNCmetal prototypes • SLA Prototyped parts are well suited for • Form, and Fit tests. • Some function testing

26. Selective Laser Sintering (SLS) • Uses a high power laser to sinter together fusible materials, such as powdered metals, layer by layer. • Sintering is the heating and fusing of small particles resulting in a hard bonded material block. • The un-sintered powder supports the part as the layers are sintered.

28. Fused Deposition Model (FDM) Filament Spool Drive Wheels Head Heater Head motion Molten filament Fused Part Table motion Table

29. FDM System  Stratasys 3000 (Courtesy of Stratasys Corporation)

30. FDM MotorCycle Cowling (Courtesy of Stratasys Corporation)

31. Fused Deposition Model (FDM) • FDM Parts can be made from: high strength ABS plastic, impact resistant ABS, investment casting wax, and some elastomers. • FDM ProtoTypesparts are well suited for • Form, and Fit tests. • Some function testing

32. 3-D Inkjet prototyping • Glue-like binder selectively “printed” onto a layer of dry powder, layer by layer, which dries into a solid prototype. • Similar process uses a print head to deposit a thermoplastic material, layer by layer. • Quick and inexpensive • The processes work well as concept modelers. • Prototypes have limited dimensional tolerances • Somewhat fragile unless coated with a hardener • Prototypes made with this process are typically NOT function tested.

33. 3-D Inkjet ProtoTyping

34. Z-Corporaton Z406 (“Inkjet”) (Courtesy of Z-Corporation)

35. 3D InkJet Chrome Wheel (Courtesy of Z-Corporation)

36. 3D InkJetFanHousing

37. Laminated Object Manufacturing • Laminating thin layers of paper, polymer or sheet steel, which have been cut using a numerically controlled laser. • LOM prototypes can be sanded to reduce jagged edges, but are not able to be function tested such as for stress or strain due to the anisotropic material properties of the laminate.

38. LOM

39. RP Service Bureaus • Product manufacturer emails the solid model part file to the service bureau, typically as an *.STL file. • The bureau uses its software to convert the *.STL file to a “sliced” file format specific to the selected prototyping hardware (i.e. FDM, SLA, SLS, LOM), • Part is fabricated along with any duplicates.

40. Compare: RP & Traditional • Shape generating compatibility – Can the material be formed into the needed geometric features to adequately represent the part? • Function testing validity – Are the material properties representative, or scalable such that the part when reduced (or expanded) in size, can be validly tested? • Fabrication costs – Will the prototype costs for materials and labor be acceptable? • Fabrication time – How long will it take to fabricate the original and one or more duplicates?

41. Engineering Tests • Mechanical  modes of failure • Manufacturability • Operation & Maintenance • Safety • Environmental • EngineeringTests ≠ Experiments • Experiments validate phenomena

42. static strength fatigue deflection/stiffness creep, impact vibration thermal/heat transfer Fluid Containment energy consumption or production friction (i.e. too much, too little) wear lubrication corrosion life, reliability Mechanical Failure Modes

43. Manufacturability • ProtoType Testing Provides Valuable information on Manufacturing Concerns • process compatibility/precision • process technology readiness • raw material quality • assembly

44. Operation & Maintenance • ProtoType Testing Provides Valuable information on O&M Concerns • Installation • styling/aesthetics • Ergonomics • Scheduled maintenance • Repairs • O&M Tooling Development

45. Safety Concerns • ProtoType Testing Provides Valuable information on Safety Concerns • risk to user, product liability • risk to consumer/society • safety codes, standards (UL, NFPA, NEC) • risk to production worker (e.g. OSHA) • FailSafe Operation • Seismic Restraint/Tolerance • Etc.

46. Environmental Protection • ProtoType Testing Provides Valuable information on Environmental Impact • Effluent Discharge: • Gaseous  Air Pollution • Liquid  Water Pollution • Solid  Ground Pollution • Loud Noise • Intense Light • RadioActivity

47. Engineering-Test Planning • A Good Plan for an Engineering Test Lists: • Objectives • list of items (parts, systems, models) to be tested • purposes for which the tests are being conducted • WorkScope – narrative description: • type of tests, • test descriptions/procedures, • experimental setup, • experimental controls, • design of experiments test matrix • list of deliverables. • Budget • Schedule

48. Summary • Companies build and test prototypes to ensure form, fit and function. • Product development tests include: product-concept, proof-of-concept, virtual, alpha, beta, and preproduction. • Prototypes can be built using traditional and rapid prototyping methods and materials. • Rapid prototyping methods include NC/CNC, SLA, FDM, LOM, SLS, and 3-D Inkjet printing

49. Summary • Rapid prototyping takes advantage of CAD • Part and product testing can include tests for: mechanical modes of failure, manufacturability, user operation & maintenance, safety and environmental protection. • Product development often requires the preparation and completion of a detailed test plan.

50. All Done for Today • HALT = Highly Accelerated Life Testing • HALT is used to find the weak links in the design and fabrication processes of a product during the design phase. • The stresses are not meant to simulate the field environments at all, but to find the weak links in the design and processes using only a few units. The stresses are stepped up to well beyond the expected field environment until the “fundamental limit of the technology” is reached. H.A.L.T.Testing