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2.008-spring-2004 S.Kim

2.008 Design & Manufacturing II Spring 2004 Assembly & Joining. 2.008-spring-2004 S.Kim . 1. Dexter ’ s Plastic Can. -cool ? -gas leakage ? -recycling?.

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2.008-spring-2004 S.Kim

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  1. 2.008 Design & Manufacturing II Spring 2004 Assembly & Joining 2.008-spring-2004 S.Kim 1

  2. Dexter’s Plastic Can -cool ? -gas leakage ? -recycling? 2.008-spring-2004 S.Kim 2

  3. A 2002 Yo-Yo vs. a free gift 2.008-spring-2004 S.Kim 3

  4. Guidelines to Assembly Design Minimize parts Design assembly process in a layered fashion Consider ease of part handling Utilize optimum attachment methods Consider ease of alignment and insertion Avoid design features that require adjustments 2.008-spring-2004 S.Kim 4

  5. Manufacturing Market Research Conceptual Design Contributions on the final cost? Unit Manufacturing Processes Assembly and Joining •Machining •Injection molding •Casting •Stamping •Chemical vapor deposition •Welding •Bolting •Bonding •Soldering Factory, Systems & Enterprise 2.008-spring-2004 S.Kim 5

  6. Cost of Design Changes time J.Chun and http://www.lboro.ac.uk/departments/mm/research/product- realisation/res_int/ipps/dfa1.htm 2.008-spring-2004 S.Kim 6

  7. Typical Cost Breakdown Selling Price Engineering 14% R&D 5% Manufacturing Costs Plant Admin, sales Machinery 24% 12% Manufacturing 38% Parts, Material 50% Indirect labor 26% Profit 19% Direct labor 12% 2.008-spring-2004 S.Kim 7

  8. Assembly business Industry % Workers in Assembly Automobile Aircraft Telephone & Telegraph Farm Machinery Home appliances Two-wheel vehicles M. Culpepper 2.008-spring-2004 S.Kim 8

  9. Optical Connectors MT connector Alignment errors 2.008-spring-2004 S.Kim 9

  10. Initial Quality Study IQS: Problems experienced after 90 days of ownership per 100 vehicles 0 to 100, 100 to 200, 200 and over 2.008-spring-2004 S.Kim 10

  11. The automobile industry, 1980’s Problem “fine and fix” Product Launch (US company) Problem prevention (Japanese company) Design Changes per Week SOP Months Relative to Product Launch Sullivan, 1986 2.008-spring-2004 S.Kim 11

  12. Good Design DFMA (Design for Mfg. & Assembly) Simplicity for both human operators and robots Even Kids can do. http://order.tupperware.com:8080/coe- images/items/10044822000_detail.jpg 2.008-spring-2004 S.Kim 12

  13. DFA guide Simplicity is the best DFA. Minimize part numbers, operations, simplify assembly sequence (steps) and set-ups  Standardize components, use suppliable common parts  Minimize assembly directions (layered structure) Figure 3.3. Can and bottle opener. This bottle/can opener satisfies two FRs: (1) opens cans, and (2) opens bottles. If the requirement is not to perform these two functions simul- taneously, then this physically integrated device satisfies two independent FRs. N. Suh 2.008-spring-2004 S.Kim 13

  14. DFA guide (cont.) Modular design, product families, assembly friendiness Use symmetrical parts Physical integration Minimize sharp, delicate, flexible, slippery part Relax tolerances on non-critical locations. Approachable, line of sight Fragile/Sharp Symmetry Size Slippery/Flexible 2.008-spring-2004 S.Kim 14

  15. DFA Guide (cont.) Material for DFA, avoid flexible components Concurrent engineering Design for disassembly (recycling, repair, retrofit) 2.008-spring-2004 S.Kim 15

  16. DFMA Hitachi assemblability evaluation method Lucas DFA  Boothroyd-Dewhurst DFA (BD) 2.008-spring-2004 S.Kim 16

  17. Design for Assembly Number of parts 2.008-spring-2004 S.Kim 17

  18. Pneumatic Piston Sub-Assembly screw 1 – snap on cover and stop (plastic) cover spring 2 – spring(steel) 3 – piston (aluminum) piston stop piston 4 – main block (plastic) main block Redesigned T. Gutowski 2.008-spring-2004 S.Kim 18

  19. DFA: Examples Pa rt ca n jam when Tape ring the hol e inserted into hole . facilitates part insertion. Alignment 2.008-spring-2004 S.Kim 19

  20. DFA for Automation: Examples Parts are difficultChanging part geometry to align properly; allows it to be aligned properly jamming can occur. before it is released. Parts are difficult Chamfers assist to assemble . assem bly. 2.008-spring-2004 S.Kim 20 Kalpakjian, Benhabib

  21. Assembly automation Challenges Parts Feeding Sorting Orienting  Pick-and-place Assembly PCB assembly? 2.008-spring-2004 S.Kim 21

  22. Non-vibratory Feeding Rotary mechanism with multiple blades Groove Hopper Rotation axis Inclined discharge rail B. Benhabib 2.008-spring-2004 S.Kim 22

  23. Vibratory Parts Feeding Track Outlet Translational vibration Torsional vibration Bowl Electromagnet Leaf springs Base 2.008-spring-2004 S.Kim 23 B. Benhabib

  24. Vibratory Feeding -orientation Second attachment (rejects c andd ) First attachment (rejects a and b ) Third attachment (orients e and f ) Discharge hole Side view Top view 2.008-spring-2004 S.Kim 24 B. Benhabib

  25. Magnetic Parts Feeding Delivery chute Parts picked up by magnets Stationary hopper Magnets Parts 2.008-spring-2004 S.Kim 25

  26. DFA for Transporting Non-functional peg prevents jamming. Wider edge surface prevents overlap. Flat ends prevent jamming. 2.008-spring-2004 S.Kim 26 B. Benhabib

  27. Automated Assembly • Transfer • Transfer lines • Conveyor • Automated Guided Vehicle • Positioner • Assembly Operations 2.008-spring-2004 S.Kim 27

  28. Transfer Lines Work carriers Fixed rail Stop Step Piston Transfer rail Slide 2.008-spring-2004 S.Kim 28

  29. Rotary Assembly Transfer Positioning unit Riveter Feedtrack Vibratory bowl Adhesive-bond applicator Completed pieces Inspection station 2.008-spring-2004 S.Kim 29 B. Benhabib

  30. AGV Workpiece Pallet load / unload mechanism Pallet Safeguards against collision 2.008-spring-2004 S.Kim 30

  31. Pick & Place Positioner • Fixed-length arm • Linear actuator • Rotary actuator • Gripper Rotary actuator Fixed base 2.008-spring-2004 S.Kim 31

  32. Robot Arm Elbow extension Hydraulic/electric power unit Shoulder swivel Yaw Wrist Arm sweep Robot controller Pitch 2.008-spring-2004 S.Kim 32

  33. Robots: Components • Manipulator • positioning • power • stiffness • control • End effector • tooling 2.008-spring-2004 S.Kim 33

  34. Robots: Applications • 3 D’s (Dull, Dirty, Dangerous) • 3 H’s (Hot, Heavy, Hazardous) • Materials handling • Spray painting • Spot welding • Arc welding • Assembly 2.008-spring-2004 S.Kim 34 J. Chun

  35. Good Design Principles: DFM Assembly • Design parts to be self-locating and self-aligning • Error-proof parts to make incorrect assembly impossible • Minimize the number of parts. • Minimize the number and variety tools for assembly • Minimize the number of axes of insertion • Ensure clear vision and access for all assembly operations • Minimize the number and complexity of adjustments • Eliminate the need to hold down, clamp or fixture parts • Eliminate special assembly tools Alignment 2.008-spring-2004 S.Kim 35

  36. What assembly process to choose? Reasons to avoid assembly Reasons that justify assembly 2.008-spring-2004 S.Kim 36

  37. Workholding • Immobilization of a workpiece for machining • or assembly • Jigs: locating and holding workpiece, guiding tools • Fixtures: locating and holding • Provide maximum accuracy and ease of • mounting •  Datum 2.008-spring-2004 S.Kim 37

  38. 3-2-1 rule of locating 6 dof, (Dx,Dy,Dz) and (Rx,Ry,Rz) 3 support Points (1, 2 and 3) eliminate (Rxand Ry) and (-Dz); 2 points (4 and 5) eliminate (Rz) and (- Dx); and, 1 point (6) eliminates (-Dy). Push or clamp 3 directions, x,y,z. Direction of resultant clamping force 2.008-spring-2004 S.Kim 38 B. Benhabib

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