Manufacturing - CAMOutlineIntroduction to ManufacturingLife Cycle: Conceive, Design, ImplementSimple Manufacturing PlantRaw MaterialsMetal Cutting/Removal TechniquesQuality: Engineering TolerancesProcess Capability IndicesRate: ManufacturingLearning Curve EquationCost: Driving FactorsProcess SelectionFlexibility: UncertaintiesFlexibility of process technologiesTypes of Flexibilities and their LinkageSpiral Development (DSM)16.810 (16.682) 16.810 (16.682) Engineering Design and Rapid PrototypingEngineering Design and Rapid PrototypingInstructor(s)Lecture 6Manufacturing - CAMJanuary 14, 2004Prof. Olivier de Weck Dr. Il Yong [email protected] [email protected] (16.682)2Outline Introduction to Manufacturing Parts Fabrication and Assembly Metrics: Quality, Rate, Cost, Flexibility Water Jet Cutting Video Sequence B777 Manufacturing Role of Manufacturing in a Real World Context OMax Introduction Computer Aided (Assisted) Manufacturing Converting a drawing to CNC Routing Instructions16.810 (16.682)3Course Flow DiagramCAD/CAM/CAE IntroFEM/Solid Mechanics OverviewManufacturing TrainingStructural Test “Training”Design OptimizationHand sketchingCAD designFEM analysisProduce Part 1TestProduce Part 2OptimizationProblem statementFinal ReviewTestLearning/Review DeliverablesDesign Sketch v1Analysis output v1Part v1Experiment data v1Design/Analysis output v2Part v2Experiment data v2Drawing v1Design IntroDueDueWed, Jan 21Wed, Jan 2116.810 (16.682)4Introduction to Manufacturing Manufacturing is the physical realizationof the previously designed parts Metrics to assess the “performance” of mfg  Quality  does it meet specifications? Rate  how many units can we produce per unit time? Cost  What is the cost per unit? What is the investment cost in machinery & tooling? Flexibility  what else can be make with our equipment? How long does it take to reconfigure the plant?16.810 (16.682)5Life Cycle: Conceive, Design, Implement1Beginningof Lifecycle-Mission- Requirements-ConstraintsCustomerStakeholderUserArchitectDesignerSystem EngineerConceiveDesignImplement“process information”“turninformationto matter”SRRPDRCDRiterateiterateThe EnvironmentThe Environment: technological, economic, political, social, natureThe EnterpriseThe EnterpriseThe SystemThe Systemcreativityarchitectingtrade studiesmodeling simulationexperimentsdesign techniquesoptimization (MDO)virtualrealManufacturingassemblyintegrationchoosecreate16.810 (16.682)6Simple Manufacturing PlantWarehousePF1…PFnQA1…QAnPartsBufferSupplierBufferAssemblyFinal InspectionFinishedGoodsPF = Parts Fabrication(focus of this lecture)QA = Quality AssuranceRaw MaterialsEnergySupplied PartsLaborMoneySalesScrapEmissions16.810 (16.682)7Raw Materials Material Selection Strength Density Cost … Form Sheet Rods, ...Ashby Diagram16.810 (16.682)8Parts Manufacturing example: deck components Ribbed-bulkheads Approximate dimensions 250mm x 350mm x 30mm Wall thickness = 2.54mmdecks Fundamental Parts Fabrication Techniques Machining – e.g. milling, laser and waterjet cutting ... Forming – e.g. deep drawing, forging, stamping Casting - fill die with liquid material, let cool  Injection Molding - mainly polymers Layup – e.g. Pre-preg composite manufacturing Sintering - form parts starting from metal powder16.810 (16.682)9Metal Cutting/Removal TechniquesTurning on a latheMillingPlaningDrillingCountersinkingSlottingGrindingReamingNew Techniques:Laser Cutting(mainly for sheetmetal)Waterjet CuttingReaming16.810 (16.682)10Quality: Engineering Tolerances Tolerance --The total amount by which a specified dimension is permitted to vary(ANSI Y14.5M) Every componentwithin spec addsto the yield (Y)qp(q)LUYyp(y)16.810 (16.682)11Process Capability Indices Process Capability Index Bias factor  Performance Index()CULp≡− /23σCC kpk p≡−()1kULUL≡−+−µ22()/p(q)qLUUL+2UL−216.810 (16.682)12Rate: Manufacturing Typically: #of units/hour The more parts we make (of the same kind), the lower the cost/unit Learning Curve effects Higher Speed - Human learning Reduced setup time Fewer Mistakes (= less scarp=higher yield) Bulk quantity discounts (=economies of scale) Better negotiating position with suppliers of raw materials and parts16.810 (16.682)13Learning Curve Equation Credited to T.P. Wright [1936] Model cost reduction between first production unit and subsequent units Model the total production cost of Nunits()BtotalCNTFUN=⋅()ln 100%1ln 2SB ≡−S=90% Learning Curve0.000.200.400.600.801.001.201 3 5 7 9 11 13 15 17 19Number of Units ProducedCost/UnitS=90%B=0.85TFU=1TFU= Theoretical first unit costS= learning curve slope in %--> percentage reduction in cumulativeaverage cost, each time the numberof production units is doubledRecommended:2<N<10 S=95%10<N<50 S=90%N>50 S=85%16.810 (16.682)14Cost: Driving Factors Cost/Unit [$] Depends on Manufacturing process chosen Number of Parts made Skill and Experience of worker(s), Salary Quality of Raw Materials Reliability of Equipment Energy Costs Land/Facility Cost Tolerance Level (Quality)16.810 (16.682)15Process Selectiontot fixed var()CN C C N=+⋅- Machine -Tools- Training-Time/part-Material-EnergyFixed cost process 1Total cost process 2TotalManufacturingCost [$]N - number of parts producedTotal Costprocess 1Fixed cost process 2Choose2Choose1E.g.Waterjet CuttingE.g. Stamping16.810 (16.682)16Flexibility: Uncertainties Short market cycles Distinct customers with changing needs Changes in laws, regulations & standardsª Uncertainties in products and, therefore, in single parts! How to address these uncertainties?ª Flexibility as ‘Magic bullet’?16.810 (16.682)17Flexibility of process technologiesHigh Speed MachiningForming technologyPunchingCastingSet-up timeOutput rate⎥⎦⎤⎢⎣⎡FixVarCCPrototyping Flexibility is the ease with which a system can change from one state to another! Which process is more flexible than others?What type of flexibility?16.810 (16.682)18Types of Flexibilities and their LinkageComponent or Basic FlexibilitiesSystem Flexibilities Aggregate FlexibilitiesOrganizational StructureMicroprocessor TechnologyProcessRoutingProductVolumeExpansionMachineMaterial HandlingOperationProgramProductionMarket16.810 (16.682)19Waterjet - Brief history- Industrial uses of