Dexter’s Plastic Can A 2002 Yo-Yo vs. a free gift II
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Dexter’s Plastic Can 2.008 Design & Manufacturing II Spring 2004 Assembly & Joining -cool ? -gas leakage ? -recycling? 2.008-spring-2004 S.Kim 1 A 2002 Yo-Yo vs. a free gift Guidelines to Assembly Design 3 2.008-spring-2004 S.Kim Manufacturing Market Research Conceptual Design 2 2.008-spring-2004 S.Kim 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 4 2.008-spring-2004 S.Kim Cost of Design Changes $$$$ Design for Manufacture time RELEASE 10,000X Assembly Contributions on the final cost? 1000X TOOLING Unit Manufacturing Processes Assembly and Joining Factory, Systems & Enterprise 2.008-spring-2004 S.Kim •Welding •Bolting •Bonding •Soldering 100X DESIGN 10X CONCEPT •Machining •Injection molding •Casting •Stamping •Chemical vapor deposition X 5 2.008-spring-2004 S.Kim J.Chun and http://www.lboro.ac.uk/departments/mm/research/productrealisation/res_int/ipps/dfa1.htm 6 1 Assembly business Typical Cost Breakdown Selling Price Engineering 14% R&D 5% Manufacturing Costs Plant Machinery 12% Admin, sales 24% Manufacturing 38% Profit 19% Parts, Material 50% Indirect labor 26% Direct labor 12% 7 2.008-spring-2004 S.Kim Optical Connectors 2.008-spring-2004 S.Kim M. Culpepper 8 Initial Quality Study MT connector IQS: Problems experienced after 90 days of ownership per 100 vehicles 0 to 100, 100 to 200, 200 and over Alignment errors 9 2.008-spring-2004 S.Kim 10 2.008-spring-2004 S.Kim Good Design DFMA (Design for Mfg. & Assembly) The automobile industry, 1980’s SOP Simplicity for both human operators and robots Even Kids can do. 2.008-spring-2004 S.Kim Sullivan, 1986 11 2.008-spring-2004 S.Kim http://order.tupperware.com:8080/coeimages/items/10044822000_detail.jpg 12 2 DFA guide DFA guide (cont.) 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 2.008-spring-2004 S.Kim 13 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 DFMA Material for DFA, avoid flexible components Concurrent engineering Hitachi assemblability evaluation method Lucas DFA Boothroyd-Dewhurst DFA (BD) 14 2.008-spring-2004 S.Kim Design for disassembly (recycling, repair, retrofit) 15 2.008-spring-2004 S.Kim Pneumatic Piston Sub-Assembly Design for Assembly 1) 2) screw spring piston Assembly cost ($) 1.0 0.9 piston stop Redesigned 0.1 0 2.008-spring-2004 S.Kim cover main block Annual production volumes : robotic - 200,000 automatic - 2,400,000 0.8 0.7 0.6 0.5 0.4 0.3 0.2 16 2.008-spring-2004 S.Kim 24 8 2 4 Number of parts 17 2.008-spring-2004 S.Kim T. Gutowski 18 3 DFA: Examples DFA for Automation: Examples Part can jam when inserted into hole. Tapering the hole facilitates part insertion. Parts are difficult to asse mble. 19 2.008-spring-2004 S.Kim Parts are difficult Changing part geometry to align properly; allows it to be aligned properly jamming can occur. before it is released. Kalpakjian, Benhabib 2.008-spring-2004 S.Kim Assembly automation 20 Non-vibratory Feeding Rotary mechanism with multiple blades Challenges Parts Feeding Chamfers assist assem bly. Groove PCB assembly? Hopper Sorting Orienting Pick-and-place Assembly Rotation axis 21 2.008-spring-2004 S.Kim Vibratory Parts Feeding B. Benhabib 2.008-spring-2004 S.Kim Second attachment (rejects c and d) Outlet 22 Vibratory Feeding -orientation Track First attachment (rejects a and b) Translational vibration Torsional vibration Bowl Electromagnet Inclined discharge rail Third attachment (orients e and f) Leaf springs Discharge hole Base Side view a b c d e f Top view 2.008-spring-2004 S.Kim B. Benhabib 23 2.008-spring-2004 S.Kim B. Benhabib 24 4 Magnetic Parts Feeding DFA for Transporting Delivery chute Parts picked up by magnets Non-functional peg prevents jamming. Stationary hopper Magnets Parts Wider edge surface prevents overlap. Flat ends prevent jamming. 25 2.008-spring-2004 S.Kim Automated Assembly B. Benhabib 2.008-spring-2004 S.Kim Transfer Lines Work carriers Stop Transfer 26 Fixed rail Step Piston Transfer lines Conveyor Automated Guided Vehicle Transfer rail Slide Positioner Assembly Operations 27 2.008-spring-2004 S.Kim Rotary Assembly Transfer J. Chun 2.008-spring-2004 S.Kim 28 AGV Workpiece Positioning unit Pallet load / unload mechanism Riveter Pallet Feedtrack Vibratory bowl Adhesive-bond applicator Completed pieces 2.008-spring-2004 S.Kim Inspection station B. Benhabib Safeguards against collision 29 2.008-spring-2004 S.Kim 30 5 Pick & Place Positioner Robot Arm Elbow extension Fixed-length arm Hydraulic/electric power unit Shoulder swivel Linear actuator Rotary actuator Gripper Rotary actuator Yaw Fixed base Wrist Arm sweep Robot controller 31 2.008-spring-2004 S.Kim Robots: Applications Manipulator positioning power stiffness control End effector tooling 2.008-spring-2004 S.Kim 33 Good Design Principles: DFM Assembly 2.008-spring-2004 S.Kim 3 D’s (Dull, Dirty, Dangerous) 3 H’s (Hot, Heavy, Hazardous) Materials handling Spray painting Spot welding Arc welding Assembly J. Chun 34 What assembly process to choose? 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 2.008-spring-2004 S.Kim 32 2.008-spring-2004 S.Kim Robots: Components Pitch 35 Reasons to avoid assembly Reasons that justify assembly 2.008-spring-2004 S.Kim 36 6 Workholding Immobilization of a workpiece for machining or assembly 3-2-1 rule of locating Jigs: locating and holding workpiece, guiding tools Fixtures: locating and holding 6 dof, (Dx, Dy, Dz) and (Rx, Ry, Rz) 3 support Points (1, 2 and 3) eliminate (Rx and 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. Provide maximum accuracy and ease of mounting Datum Z Rz Ry Dy Dx X 2.008-spring-2004 S.Kim Direction of resultant clamping force Dz 37 2.008-spring-2004 S.Kim Rx Y 5 4 6 1 2 B. Benhabib 3 38 7
