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2.008-spring-2004 S.Kim 2.008 Design & Manufacturing II Spring 2004 Assembly & Joining 1
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2.008-spring-2004 S.Kim 2 Dexter ’ s Plastic Can -cool ? -gas leakage ? -recycling?
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2.008-spring-2004 S.Kim 3 A 2002 Yo-Yo vs. a free gift
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2.008-spring-2004 S.Kim 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
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2.008-spring-2004 S.Kim 5 Manufacturing Market Research Conceptual Design Factory, Systems & Enterprise Unit Manufacturing Processes Contributions on the final cost? Welding Bolting Bonding Soldering Machining Injection molding Casting Stamping Chemical vapor deposition Assembly and Joining
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2.008-spring-2004 S.Kim 6 Cost of Design Changes J.Chun and http://www.lboro.ac.uk/departments/mm/research/product- realisation/res_int/ipps/dfa1.htm time
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2.008-spring-2004 S.Kim 7 Typical Cost Breakdown Selling Price Engineering 14% R&D 5% Admin, sales 24% Manufacturing 38% Manufacturing Costs Plant Machinery 12% Indirect labor 26% Direct labor 12% Parts, Material 50% Profit 19%
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2.008-spring-2004 S.Kim 8 Assembly business M. Culpepper Industry % Workers in Assembly Automobile Aircraft Telephone & Telegraph Farm Machinery Home appliances Two-wheel vehicles
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2.008-spring-2004 S.Kim 9 Optical Connectors MT connector Alignment errors
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2.008-spring-2004 S.Kim 10 Initial Quality Study Problems experienced after 90 days of ownership per 100 vehicles IQS: 0 to 100, 100 to 200, 200 and over
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2.008-spring-2004 S.Kim 11 The automobile industry, 1980 ’ s Sullivan, 1986 Problem “fine and fix” (US company) Problem prevention (Japanese company) Product Launch SOP Months Relative to Product Launch Design Changes per Week
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2.008-spring-2004 S.Kim 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
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2.008-spring-2004 S.Kim 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) N. Suh 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.
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2.008-spring-2004 S.Kim 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 Size Fragile/Sharp Slippery/Flexible Symmetry
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2.008-spring-2004 S.Kim 15 DFA Guide (cont.) Material for DFA, avoid flexible components Concurrent engineering Design for disassembly (recycling, repair, retrofit)
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2.008-spring-2004 S.Kim 16 DFMA Hitachi assemblability evaluation method Lucas DFA Boothroyd-Dewhurst DFA (BD)
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2.008-spring-2004 S.Kim 17 Design for Assembly Number of parts
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2.008-spring-2004 S.Kim 18 Pneumatic Piston Sub-Assembly T. Gutowski screw spring piston cover piston stop main block Redesigned 1 – snap on cover and stop (plastic) 2 – spring(steel) 3 – piston (aluminum) 4 – main block (plastic)
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2.008-spring-2004 S.Kim 19 DFA: Examples Pa rt ca n jam when Tape ring the hol e inserted into hole. facilitates part insertion. Alignment
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2.008-spring-2004 S.Kim 20 DFA for Automation: Examples Parts are difficult Chamfers assist to assemble. assem bly. Parts are difficult Changing part geometry to align properly; allows it to be aligned properly jamming can occur. before it is released. Kalpakjian, Benhabib
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2.008-spring-2004 S.Kim 21 Assembly automation Challenges Parts Feeding Sorting Orienting Pick-and-place Assembly PCB assembly?
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2.008-spring-2004 S.Kim 22 Non-vibratory Feeding Groove Hopper Rotation axis Rotary mechanism with multiple blades Inclined discharge rail B. Benhabib
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2.008-spring-2004 S.Kim 23 Vibratory Parts Feeding B. Benhabib Track Bowl Electromagnet Outlet Leaf springs Base Translational vibration Torsional vibration
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Vibratory Feeding -orientation Second attachment (rejects c and d ) First attachment (rejects a and b ) Third attachment (orients e and f ) Side view Top view Discharge hole B. Benhabib 2.008-spring-2004 S.Kim 24
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2.008-spring-2004 S.Kim 25 Magnetic Parts Feeding Parts picked up by magnets Delivery chute Magnets Parts Stationary hopper
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DFA for Transporting Flat ends prevent jamming. Non-functional peg prevents jamming. Wider edge surface prevents overlap. B. Benhabib 2.008-spring-2004 S.Kim 26
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2.008-spring-2004 S.Kim 27 Automated Assembly Transfer Transfer lines Conveyor Automated Guided Vehicle Positioner Assembly Operations
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2.008-spring-2004 S.Kim 28 Transfer Lines Piston Stop Work carriers Fixed rail Step Transfer rail Slide
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2.008-spring-2004 S.Kim 29 Rotary Assembly Transfer B. Benhabib Positioning unit Riveter Adhesive-bond applicator Inspection station Completed pieces Vibratory bowl Feedtrack
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2.008-spring-2004 S.Kim 30 AGV Pallet load / unload mechanism Workpiece Pallet Safeguards against collision
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2.008-spring-2004 S.Kim 31 Pick & Place Positioner Linear actuator Rotary actuator Gripper Fixed-length arm Rotary actuator Fixed base
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Shoulder swivel Robot Hydraulic/electric power unit Elbow extension Arm Robot controller Arm sweep Pitch Yaw Wrist 2.008-spring-2004 S.Kim 32
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2.008-spring-2004 S.Kim 33 Robots: Components Manipulator positioning power stiffness control End effector tooling
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2.008-spring-2004 S.Kim 34 Robots: Applications 3 D’s (Dull, Dirty, Dangerous) 3 H’s (Hot, Heavy, Hazardous) Materials handling Spray painting Spot welding Arc welding Assembly J. Chun
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2.008-spring-2004 S.Kim 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
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2.008-spring-2004 S.Kim 36 What assembly process to choose? Reasons to avoid assembly Reasons that justify assembly
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2.008-spring-2004 S.Kim 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
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3-2-1 rule of locating 6 dof, (D x,D y,D z ) and (R x,R y,R z ) 3 support Points (1, 2 and 3) eliminate (R x and R y ) and (-D z ); 2 points (4 and 5) eliminate (R z ) and (- D x ); and, 1 point (6) eliminates (-D y ). Push or clamp 3 directions, x,y,z. Direction of resultant clamping force B. Benhabib 2.008-spring-2004 S.Kim 38
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