12.008-spring-2004 S.Kim 12.008 Design & Manufacturing IISpring 2004Assembly & Joining2.008-spring-2004 S.Kim2Dexter’s Plastic Can-cool ? -gas leakage ? -recycling? 2.008-spring-2004 S.Kim3A 2002 Yo-Yo vs. a free gift2.008-spring-2004 S.Kim4Guidelines 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 adjustments2.008-spring-2004 S.Kim5ManufacturingUnit ManufacturingProcessesAssembly and JoiningDesign forManufactureMarketResearchConceptualDesignFactory, Systems & Enterprise•Welding•Bolting•Bonding•Soldering•Machining•Injection molding•Casting•Stamping•Chemical vapor depositionContributions on the final cost?2.008-spring-2004 S.KimJ.Chun and http://www.lboro.ac.uk/departments/mm/research/product-realisation/res_int/ipps/dfa1.htm 6Cost of Design ChangesCONCEPTDESIGNX10XTOOLINGAssembly100X1000XRELEASE10,000X$$$$ time22.008-spring-2004 S.Kim7Typical Cost BreakdownSelling PriceAdmin, sales24%Profit19%R&D5%Manufacturing38%Engineering14%Manufacturing CostsDirect labor12%Parts, Material50%Indirect labor26%Plant Machinery12%2.008-spring-2004 S.KimM. Culpepper 8Assembly business2.008-spring-2004 S.Kim9Optical ConnectorsAlignment errorsMT connector2.008-spring-2004 S.Kim10Initial Quality StudyIQS:Problems experienced after 90 days of ownership per 100 vehicles0 to 100, 100 to 200, 200 and over2.008-spring-2004 S.KimSullivan, 1986 11The automobile industry, 1980’sSOP2.008-spring-2004 S.Kimhttp://order.tupperware.com:8080/coe-images/items/10044822000_detail.jpg 12Good Design DFMA (Design for Mfg. & Assembly)Simplicity for both human operators and robotsEven Kids can do.32.008-spring-2004 S.KimN. Suh 13DFA 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)2.008-spring-2004 S.Kim14DFA 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 sight2.008-spring-2004 S.Kim15DFA Guide (cont.) Material for DFA, avoid flexible components Concurrent engineering Design for disassembly (recycling, repair, retrofit)2.008-spring-2004 S.Kim16DFMA Hitachi assemblability evaluation method Lucas DFA Boothroyd-Dewhurst DFA (BD)2.008-spring-2004 S.Kim17Design for Assembly0.10.20.30.40.50.60.70.80.91.00248 42Annual production volumes :robotic - 200,000automatic - 2,400,000Assembly cost ($)Number of parts1) 2)2.008-spring-2004 S.KimT. Gutowski 18Pneumatic Piston Sub-Assemblyscrewspringpistoncoverpiston stopmain blockRedesigned42.008-spring-2004 S.Kim19DFA: ExamplesPa r t ca n jam wh e n inserted into hole.Tapering the hole facilitatespart insertion.2.008-spring-2004 S.KimKalpakjian, Benhabib 20DFA for Automation: ExamplesParts are difficult to assemble.Chamfers assist assembly.Parts are difficult to align properly;jamming can occur.Changing part geometryallows it to be aligned properlybefore it is released.2.008-spring-2004 S.Kim21Assembly automationChallenges Parts Feeding SortingOrienting Pick-and-place AssemblyPCB assembly?2.008-spring-2004 S.KimB. Benhabib 22Non-vibratory FeedingGrooveRotary mechanism with multiple bladesHopperRotation axisInclined discharge rail2.008-spring-2004 S.KimB. Benhabib 23Vibratory Parts FeedingBowlOutletLeaf springsBaseElectromagnetTrackTorsional vibrationTranslational vibration2.008-spring-2004 S.KimB. Benhabib 24Vibratory Feeding -orientationSecond attachment(rejects and )cdThird attachment(orients and )efDischarge holeFirstattachment(rejects and )abaSide viewTop viewbcdef52.008-spring-2004 S.Kim25Magnetic Parts FeedingParts picked up by magnetsDelivery chuteMagnetsPartsStationary hopper2.008-spring-2004 S.KimB. Benhabib 26DFA for TransportingNon-functional pegprevents jamming.Wider edge surfaceprevents overlap.Flat ends prevent jamming.2.008-spring-2004 S.Kim27Automated AssemblyTransfer Transfer lines Conveyor Automated Guided VehiclePositionerAssembly Operations2.008-spring-2004 S.KimJ. Chun 28Transfer LinesPistonStopWork carriersFixed railStepTransfer railSlide2.008-spring-2004 S.KimB. Benhabib 29Rotary Assembly TransferCompleted piecesFeedtrackVibratory bowlPositioningunitRiveterInspectionstationAdhesive-bondapplicator2.008-spring-2004 S.Kim30AGVPallet load / unload mechanismWorkpiecePalletSafeguards against collision62.008-spring-2004 S.Kim31Pick & Place PositionerLinear actuatorFixed-length armRotary actuatorRotary actuatorGripperFixed base2.008-spring-2004 S.Kim32RobotArmWristYawPitchHydraulic/electric power unitRobot controllerArm sweepElbow extensionShoulder swivel2.008-spring-2004 S.Kim33Robots: Components Manipulator positioning power stiffness control End effector tooling2.008-spring-2004 S.KimJ. Chun 34Robots: Applications 3 D’s (Dull, Dirty, Dangerous) 3 H’s (Hot, Heavy, Hazardous) Materials handling Spray painting Spot welding Arc welding Assembly2.008-spring-2004 S.Kim35Good 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 tools2.008-spring-2004 S.Kim36What assembly process to choose? Reasons to avoid assembly Reasons that justify assembly72.008-spring-2004 S.Kim37Workholding 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 Datum2.008-spring-2004 S.KimB. Benhabib 383-2-1 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