精密连接技术及其在-航空航天工业中的应用.ppt

精密连接技术及其在-航空航天工业中的应用.ppt

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精密连接技术及其在航空航天工业中的应用PrecisionJoiningTechniqueanditsApplicationinAerospaceIndustry,ShanghaiJiaoTongUniversityMaterialsScienceandEngineeringCollegeSJTUWeldingEngineeringInstitute,Contents,IntroductionConventionalweldingtechniquePrecisionjoiningtechniqueDifferencebetweenprecisionjoiningandconventionalweldingtechniqueMainapplicationareasofprecisionjoiningtechniqueSomefrequentlyusedtechniquesforprecisionjoiningMaterialinaerospaceandtheirjoiningfeaturesApplicationofprecisionjoiningtechniqueinaerospaceApplicationexamples:

ElectronicBeamBrazingforpartsinaerospaceApplicationexamples:

LaserweldingforpartsinaerospaceConclusionandprospect,Introduction,Thejoiningtechniqueisanindispensableprocessingmeansinmodernmanufacturing.Itusesthemechanical,chemicalmethods,suchaspartialheatingorwithpressure,tojointhetwopartsormaterials.Commonlytherearenon-permanentandpermanentjoint:

Non-permanentjoint:

thejointpartcanbemovedordis-assembled，e.g.hingejoint,chainjoint,screwjoint,etc.Permanentjoint:

thejointcannotbemovedordisassembledexceptdestruction,e.g.gluejoint,rivetjoint、allkindsofweldingjoints,etc.（Hereonlytheweldingjointsandtheirweldingtechniquewillbediscussed.）Weldingtechniquegenerallyusessomekindofheatsourcetopartiallyheatmaterial（especiallymetal）underthecertainprotectivecondition,sometimeswithcertainpressure,toformapermanentweldingjoint,whichmeanstheatomicormolecularconnectionbetweenthetwomaterialsorparts.,Introduction,Weldingtechniquesareincreasinglyappliedinmanufacturingofproductsthatconsistofdifferentpartswithdifferentmaterials,shapes,structuresandfunctions,toformacomplexentirebody.Thustheworkingprocedureoftheentiredworkpiececanbegreatlysimplified,thematerialcanbesavedandtheproductionefficiencycanbeincreased.Theseekingforhighqualityandlowcostofproductistheimportantstrategytogetvictoryinthemarketcompetitionformostenterprisestoday.Andthehighqualityofproductisgenerallyguaranteedbyreasonableproductdesign,reliableprocessingprecision,andeffectiveinspectionmethod.Asanimportantprocessingmeansinmanufacturingofmodernproduct,thejoiningtechniqueanditsprecisionincreasinglygetextensiveattention.Withdevelopmentoftechnology,theprecisionjoiningisbecominganeffectivewaytoreducefollowedworkingprocedures,todecreasecost,andtoimprovequality.Insomeimportantareas（suchasmicro-electronics,aerospaceetc.），theprecisionjoiningofsomemicro-structuresbecomeacriticaltechniqueforsuccessfulmanufacturing,thustheprecisionandrelibilityofjointbecomethemostimportantqualitycontrolpointofproduct.,Conventionalweldingtechnique,Theconventionalweldingtechnique,suchasSMAW,SAW,GMAW,GTAW,etc.arewidelyusedinmanufacturingandenjoythemainpopularitybecauseoftheirlowcostandsimpleoperation.Butforweldingofsomespecialmaterialsorspecialstructures,especiallysomemicro-structures,theirapplicationwouldberestrainedduetosomeshortcomings,suchas:

Lowenergydensity;Lowweldingspeedandefficiency;Lowcontrollableprecisionofweldingparameters;Lowdepth/widthratioofweldingpool,forthickworkpiecethemulti-passweldingisnecessary;WideHAZandlowperformanceofweldingjoint;Bigdistortionofworkpiece，correctionmeasuresareneeded;Lowprecisionofjoint,mechanicalpost-processingwouldbenecessaryforsomeimportantworkpiece,etc.,Precisionjoiningtechnique,Precisionjoiningtechniquewillusetheproperjoiningmethodandcontroltechniqueaccordingtothejointobject,andcontrolthejoiningprocessprecisely,soastoobtaintheanticipatedjointperformanceandprecision.Accordingtothesizeofjointobject,theprecisionjoiningtechniqueespeciallyforpackagingorassemblingofICcomponentsinmicro-electronicareaiscalledMicro-joiningtechnique.Themainpurposeofthecommonprecisionjoiningistoobtainthehighjointprecisionbesidethereliablejointstrength.Duringthemanufacturingofhot-workingproducts,theshape,sizeanddistortionofjointedcomponentswouldbepreciselycalculatedandstrictlycontrolled,sothemechanicalprocessingorothertreatmentsaregenerallynotnecessary.Themainpurposeofthemicro-joininginmicro-electronicareaistoobtainthehighconductivityandhighreliability.Sothejoiningmethodsaresomewhatdifferentfromcommonjoiningmethods.Somefactorsthatareneglectedincommonjoiningwouldbeverysensitiveundertheconditionofmicro-joining,andevenbethemaininfluencefactorforjointquality.,Differencebetweenprecisionjoiningandconventionalweldingtechnique,Mainapplicationareasofprecisionjoiningtechnique,Micro-electronics:

IC-packagingmicro-joiningAerospace:

Joiningofdifferentspecialmaterials,manufacturingofnavigationdevice,detectionradarandotherprecisioncomponents.Precisemachine:

ManufacturingofvarietyofNC-machine,robot,lasersystem,medicaldevice,presssystem,spinning,printinganddyeingdevice,semi-conductorprocessingsystem,etc.IT-Industry:

Manufacturingofvarietyofcommunicationdevice,computer,digitalproducts,instrument,sensors,etc.Automobile:

Preciseassemblyjoiningforvarietyofenginecomponentsandautomobilebodywork,etc.,Somefrequentlyusedtechniquesforprecisionjoining,PreciseJoiningTech.,Diffusionwelding,JoiningPrinciple:

Undercertainpressure,thematerialsurfacescontacteachother,andthepartialplasticdeformationoccurstodestroytheoxidationfilm,andthensomeminutejoiningpointsareformed.Withtimegoing,thetightlyjointedsurfaceswillgraduallygrowthbecauseofcreepdeformationanddiffusion,theinterspaceswilldecreaseandthejointedsurfacesincrease.Finallytheinterspacestotallydisappearandajointwillbeformed.Mainmechanismofjoining:

deformationanddiffusion,Diffusionwelding,Influencefactors:

Surfacefilm（organiccontamination,surfaceoxideandtheirproperties,etc.）SurfaceroughnessTechnologicfactors（temperature,pressure,time,etc.）ApplicationfeaturesThepreparationofmaterialjoiningsurfaceisstrict.Acertainpressureisneeded,butshouldnotresultinmacro-scopicalplasticdeformation.Ithashighweldingprecision,butlongtimeandlowefficiency.Itcanweldtheworkpiecewithcomplexshape,cavityoroverlap,withoutlimitofplatethicknessItcanwelddifferentmetals.,Diffusionwelding,Applicationexamples,Hotpressureweldingandultrasonichotpressurewelding,JoiningPrincipleHotpressureresultsintypicalplasticdeformationandmutualdiffusioninthejointzone；Ultrasonicvibrationcausefrictionbetweenthemetaljointsurfaces，thatisusefultodestroytheoxidefilm，andtoextendthepuremetaljointsurface.Withcombinationofhotpressureandultrasonic,andintegrationwithspecialtoolsandtechnologyofbonding,thejointbetweenthemetalwire,chippinsandmetalfilminelectroniccomponentcanbeformed.,Hotpressureweldingandultrasonichotpressurewelding,Joiningprocess,Hotpressureweldingandultrasonichotpressurewelding,InfluencefactorsSurfacefilm（organiccontamination,surfaceoxideandtheirproperties,etc.）Deformationpropertiesofmaterialsandtheirinter-solubilityTechnologicalfactors（temperature,pressure,ultrasonicpower,post-heatingtime,etc）ApplicationfeaturesFitformicro-joiningmetalwires,plates,orleadingwiresandchippinsUltrasonicfeatures:

strongfilm-destruction,bigjoining-area,smallheataffectiontochip;butnotsufficientdiffusionbetweenmetals,possiblechip-damagewithtoohighvibrationpower.Hotpressurefeatures:

sufficientdiffusionwithhightemperature,butweakfilm-destruction,lowjoiningstrength,andalsochip-damagewithtoohightemperature.Hotpressuredevicewithultrasonicvibration,i.e.ultrasonichotpressurewelding,cantakeadvantageofbothmethods,whichobtainsthesufficientjoiningstrength,whiledecreasingthetemperatureandultrasonicpowertoreducetheheatandvibrationinfluenceonchip.,Hotpressureweldingandultrasonichotpressurewelding,ApplicationexamplesWithhigherintegrationdensityofIC,thespacebetweenlinesgetssmaller,from2.541.7781.271.00.80.650.50.4to0.3mm。

Intechnologyofwirebonding,thegoldwirewithdiameter25m，andthegoldbeadwithdiameter5070m,canbejointedtothejoiningpointofbasepartwithpreciseultrasonichotpressurewelding.,IC-packaging,Hotpressureweldingandultrasonichotpressurewelding,Applicationexamples,Copperjointwithultrasonicwelding,Soldering,JoiningPrincipleSolderingusesthefillermetal（solder）under450C,itisalsocalledlowtemperaturebrazing.Inmicro-joining,itismainlyusedtojointtheleadwireoftheelectronicpartstoPCB.Thefrequentlyusedsolderingtechnologyincurrentproductionarewavesolderingandreflowsoldering.Wavesolderingwellsuptheliquidsolderthroughaverticalnarrowpipebymeansofapump,toformthewaveabout2040mmhigh,thesolderimpactthePCBwithcertainspeedandpressure,andinfiltrateintothespacebetweenICleadwireandPCB,toformajoint.ReflowsolderingusesthecreamsolderthatisprintedordroppedontoPCB,thenputtheSMDonitwithspecialequipment,andthenheatthesoldertofusion,i.ereflow,toformajoint.Accordingtothedifferentheatingmethods,reflowsolderinghasmanyvariantssuchasinfraredreflowsoldering,vaporreflowsoldering,laserreflowsoldering,etc.,Soldering,Influencefactors:

materialwettingability（basemetalandcoatedmetalandtheirproperties,thealloyelementsandimpurityelementsinsolder,etc.）Materialenduranceforsoldering（anti-fusionabilityofbasemetal,dissolutionspeedofbasematerialinsolder,etc.）Technologicfactors（heatingmethod,temperature,time,etc.）Applicationfeatures:

Joiningwithalargebatchatsametime,sh