先进制造技术-施平五单元

27五月2023先进制造技术--施平五单元Contents1.IntroductiontoAMT2.Computerandcommunication3.Computer-aidedengineering4.Automation5.Modernmanufacturingtechnologies25.ModernmanufacturingtechnologiesBasictheoryandmoderntechnologyTechnologicalchangeinmanufacturingengineeringisphenomenalandspeedingBasictheories(likemetalcuttingtheory)arethefoundationofthesophisticatedtechnologies35.ModernmanufacturingtechnologiesPrecisionengineeringQualityimprovementsofproductsrequirestheenhancementofprecisionofproductionsystem5.1

Modernmanufacturingtechnologies-Precisionengineering45.ModernmanufacturingtechnologiesBasicdefinitionsAccuracyAquantitativemeasureofthedegreeofconformancetorecognizednationalorinternationalstandardsofmeasurementRepeatabilityAmeasureoftheabilityofamachinetopositionatoolsequentiallywithrespecttoworkpieceundersimilarconditionsResolutionTheleastincrementofameasuringdeviceTheleastsignificantbitonadigitalmachine5.1

Modernmanufacturingtechnologies-Precisionengineering55.ModernmanufacturingtechnologiesMotionSlideSpindleRigidelementWetreatindividualelementasrigidbodyFlexiblestructureThewholestructuremaybeflexibleduetodeflectionsandjoints5.2

Modernmanufacturingtechnologies-Precisionengineering65.ModernmanufacturingtechnologiesRigidbodymotionanderrorTheslide5constraints(Y,ZmovementalongY,Z,rotationaboutX,Y,Z)1DOF(movementalongX)WecontrolX,whiletreatingtheother5DOFsaserrors5.2

Modernmanufacturingtechnologies-Precisionengineering75.ModernmanufacturingtechnologiesCategoriesofsourcesoferrorsofamachinetoolGeometricerrorsCausedbylackofstraightnessinslide-ways,staticdeflectionofmachinetool,angularerrorsDynamicerrorsCausedbymachinetoolvibration(chatter)Inherentfrequency(avoidthe1st,2nd,…)and

resonanceStiff,lightweight,well-dampedmachinetoolhaslessdynamicerrorWork-pieceeffectsMachinetooldeflectioncausedbyfixingandcuttingforcesduringcuttingprocessInertialeffectsduetomotion:over-shootonalinearmotion;periodicdeviationscausedbydynamicunbalanceduetopartasymmetryaboutrotationalaxis(likethespindleaxis)

ThermalerrorsExpansionwhenheated,contractionwhencooledTemperaturecontrol:air-condition,warming-uptimebeforeoperation5.2Modernmanufacturingtechnologies-PrecisionengineeringPerfectmachinewithouterrorsdoesnotexistAllmachinetoolshavegeometricerrors85.ModernmanufacturingtechnologiesTraditionalfinishingoperationsHoningHolesurfaceprocessingRadiallyfloating,axiallyreciprocatingmovement5.3Modernmanufacturingtechnologies-finishingoperation95.ModernmanufacturingtechnologiesTraditionalfinishingoperationsSuper-finishingPressureforceverylightStonestrokeveryshort5.3Modernmanufacturingtechnologies-finishingoperation105.ModernmanufacturingtechnologiesTraditionalfinishingoperationsLappingAbrasiveparticlesinaslurrySurfacefinish0.025~0.1µmPolishingNon-traditionalfinishingoperationChemicalmechanicalpolishingAchemicalreactionoccurred(example:siliconwaferpolishing)Electro-polishingElectrolyteattackstheprojectionsandpeaksonthework-piecesurfacetogetafinesurfacePolishingprocessusingmagneticfields5.3Modernmanufacturingtechnologies-finishingoperation115.ModernmanufacturingtechnologiesAimofCoatedtoolsTocopewiththeuniquepropertiesofnewmaterialsHighsrength,Toughness,ChemicalpropertiesCoatingmaterialGeneralcharacteristicsHighhardnessChemicalstabilityandinertnesstothework-piecematerialLowthermalconductivityGoodbondingtothesubstratetopreventflakingLittleornoporositycommonlyusedcoatingmaterialsTiN,titaniumnitride:lowfrictioncoefficient,highhardness,resistancetohightemperature,goodadhesiontosubstrate.PerformswellathighercuttingspeedTiCtitaniumcarbide:similarpropertiesTiCNtitaniumcarbonitride:goodwearresistancewhencuttingcarbonsteel,alloysteel,castironAl2O3AluminumOxide:lowthermalconductivity,highhothardness,wearresistance5.3Modernmanufacturingtechnologies-coatedtools125.ModernmanufacturingtechnologiesSubstratematerialHSS,highspeedsteelCementedcarbideCeramicSuper-hardmaterialCoatingprocessCVD,chemicalvapordepositionChemicalVaporDepositionischemicalreactionswhichtransformgaseousmolecules,calledprecursor,intoasolidmaterial,intheformofthinfilmorpowder,onthesurfaceofasubstrateInatypicalCVDprocess,thewafer(substrate)isexposedtooneormorevolatileprecursors,whichreactand/ordecomposeonthesubstratesurfacetoproducethedesireddeposit.Frequently,volatileby-productsarealsoproduced,whichareremovedbygasflowthroughthereactionchamber5.3Modernmanufacturingtechnologies-coatedtools135.ModernmanufacturingtechnologiesPVD,physicalvapordepositionavarietyofvacuumdepositionandisageneraltermusedtodescribeanyofavarietyofmethodstodepositthinfilmsbythecondensationofavaporizedformofthematerialontovarioussurfaces.Thecoatingmethodinvolvespurelyphysicalprocessessuchashightemperaturevacuumevaporationorplasmasputterbombardmentratherthaninvolvingachemicalreactionatthesurfacetobecoatedasinchemicalvapordeposition

5.3Modernmanufacturingtechnologies-coatedtoolscomputersimulationofthebasicphysicalprocessunderlyingphysicalvapourdeposition:asingleCuatomdepositedonaCusurface

145.ModernmanufacturingtechnologiesLubricatingcoatingmaterialAcoatingtoenhancelubricationincutting(especiallyindrycutting)CoatingmaterialMoS2(molybdenumdisulfide)MultilayercoatingTogetacombinedpropertyofthecuttingtoolCVD+PVDTiN+MoS2…Diamond-coatedtoolDiamond:superhard,idealmaterialformachiningabrasive,nonferrousmetalsandnonmetalliccomposites5.3Modernmanufacturingtechnologies-coatedtools155.ModernmanufacturingtechnologiesFactorsleadtotoolfailuresExtremeheat(cuttingedgetemperatureexceeds1000℃)DegradesbindersandothertoolconstituentsTriggersdetrimentalchemicalreactionsbetweentoolandwork-pieceHighpressureAbrasionShockthermalshockmechanicalshockBasicfailuremechanismsCraterwearThermaldeformationandcrackingNosewearBuilt-upedgeFractureFlankwear5.4Modernmanufacturingtechnologies-failuremechanismofcuttingtools165.ModernmanufacturingtechnologiesHighspeedmachineHighspindlespeedandfeedspeedSpindlespeedexceeds10,000rpmBenefitofHSMImprovedperformanceandproductquality(suchasfinerfinish)Reducedproductiontime,lowercostFactorshindershighspeedWeightofmobilecomponentOvershoot,tip-upofmachineCenterofgravityLowercenterofgravitycanreduceproblemliketip-upofmachineRigidity,stabilityKeytoHSMAxisdriveLinearmotorismorerigidthanballscrew,gearbox,etc.AccuracyMachineconfigurationMachineprogramming,trainingandmaintenance5.5Modernmanufacturingtechnologies-highspeedmachining175.ModernmanufacturingtechnologiesHardnessofmaterialDefinedbyitsresistancetopermanentdeformationIt’sthecombinationofelasticandplasticpropertythatdetermineamaterial’sresistancetopermanentdeformation555HRC~65HRCTensilestrengthupto2400MPaHardturningSmalldepthofcutandfeedthough,muchfasterthangrindingrigidmachinetool,andhardertools(CeramicorCBN,orcubicBoronNitride)makeshardturningpossibleProblemstoberedressWorkpiecemicrostructureinfluenced(residualstressandover-hardened)ToolwearandworkpiecesurfacequalityHardmillingTakesovertheworkofmachining45~64HRCtoolsteelbyEDM(electricaldischargemachining)Machinetool(similarrequirementtoHSM)andcuttingtool(coatedtoolwithTiCN,TiAlN,withgoodwear,heatresistance,hardness)5.6Modernmanufacturingtechnologies-hardpartmachining185.ModernmanufacturingtechnologiesPresentationstopics(Eachgroup4~8students)PrecisionmachiningDryornear-drymachiningCreep-feedgrindingMachiningofengineeringceramics5.6Modernmanufacturingtechnologies195.Modernmanufacturingtechnologies

CryogenicprocessingHeattreatmentamethodusedtoalterthephysical,andsometimeschemicalpropertiesofamaterial.Themostcommonapplicationismetallurgical.alsousedinthemanufactureofmanyothermaterials,suchasglass.205.Modernmanufacturingtechnologies

HeattreatmentHeattreatmentinvolvestheuseofheatingorchilling,normallytoextremetemperatures,toachieveadesiredresultsuchashardeningorsofteningofamaterial.Intentionally:heattreatmentappliestoprocesseswheretheheatingandcoolingaredoneforthespecificpurposeofalteringpropertiesIncidentally:heatingandcoolingoftenoccurduringothermanufacturingprocessessuchashotformingorwelding.215.Modernmanufacturingtechnologies

CommonHeattreatment

Annealing:退火atechniqueusedtorecovercoldwork（冷作）andrelaxstresseswithinametalQuenching（Hardeningandtempering)Tohardenbyquenching,ametal(usuallysteelorcastiron)mustbeheatedintotheausteniticcrystalphaseandthenquicklycooled.225.Modernmanufacturingtechnologies

CommonHeattreatment

Tempering.Untemperedmartensite,whileveryhard,istoobrittletobeusefulformostapplications.Mostapplicationsrequirethatquenchedpartsbetempered(heattreatedatalowtemperature,often150C)toimpartsometoughness.235.Modernmanufacturingtechnologies

CommonHeattreatment

Selectivehardeningallowdifferentareasofasingleobjecttoreceivedifferentheattreatments.alsocalleddifferentialhardening.Commonlyusedinhighqualityknivesandswordstreatment.TheChinese“jian”isoneoftheearliestknownexamples245.Modernmanufacturingtechnologies

CryogenicprocessingCryogenicsThebranchesofphysicsandengineeringthatinvolvethestudyofverylowtemperatures,howtoproducethem,andhowmaterialsbehaveatthosetemperatures.255.Modernmanufacturingtechnologies

CryogenicprocessingCryogenicprocessing

Cryogenicprocessingisnotasubstituteforheattreatment,butratheranextensionoftheheating-quenching-temperingcycle.265.ModernmanufacturingtechnologiesFeatureofmanufacturinginaerospaceindustryLowvolumeHighreliability,precisionrequirementsMaterialwithhighstrength,lightweight,difficulttomachineStainlesssteel(forhighweararea)Titanium,high-nickelsteelalloy(Goodpropertyatelevated

temperature,forcriticalload-bearingcomponent,likeengine)Aluminum(forstructuralcomponent)Alloy

steel(forhighstrength,highimpactapplication,likelandinggear)