SMT工艺 10(English)

LOGOSMT工艺10SMTPROCESSTRAINING10www.YS-U.comIntroduction,TechnologyTrends,AssemblyTypesandSMTComponentTechnologiesLOGOModule4–Unit3PlacementConsiderationsandFlexibilitywww.YS-U.com3ConsiderationsforPlacement-BoardSizeEquipmentadjuststomin/maxPCBorpanelsizeforvariousSMTproductsIn-lineconveyorfixturingisutilizedEdgemarginrequirementsmustbedesignedintoPCBorpanelThicknessofPCBisprocessconsiderationWorkenvelopeneedstoincludePCBsize,feeders,andplacementFiducialsonPCBareusedbycameraandcomputerforaccurateplacement4ConsiderationsforPlacement-ComponentsEachplacementtoolusuallyhandlesarangeofcomponentsizesVacuumnozzlesizedefinedbydimensionalrangeofcomponentsZ-strokesreferstocomponentmovementinup-downlocationsComponentalignmentonpick-upheadutilizesvisionChips:outline¢roidIC’s:centroid,individualleads,coplanarity,etc.Componentverificationisdone“onthefly”,checkingforcorrectcomponentvaluesEquipmentdetectsmissingparts5ConsiderationsforPlacement-FeedersComplexityofchangeoveroffeedersisprocessconsiderationNumberoffeedersrequiredequalsnumberofdifferentcomponentsinbillofmaterialsFeedermustbecompatiblewithcomponentpackagingfromvendorTapecoverpeel-backcapabilitiesbuiltintofeedersEaseofloading-pinlocatorsandelectricalconnectionsaffectprocesstimeOperatorawarenessnecessaryforfeederselectionaccuracy6ComponentPlacementSystemFlexibilityThewiderthevarietyofcomponentsamachinecanplace,themoreflexibleitisMostcommonfeedertypes:TapeandreelBulkMatrixtraysandwafflepacksMagazinesortubesVibratoryfeedersSurftapeDirectDiefeeder7TapeandReelPreferredforlargequantityproductionAbilitytoholdlargequantitiesofpartsLowerdowntimerequiredforreloadingControlledOrientationandpositionforpartsLotnumbertraceabilitycontrolThetapeisavailableinvaryingwidthsrangingfrom8mmto72mmThecomponentcarrierintapeismadeofpunchedcardboardorthermoformedplasticSuitableforpassivecomponents,discreteactives,SOJs,PLCCs,SOICs,StandardpitchQFPs,BareDies,BGAs&otherSMDsthatdonothavefragileleads8Siemens:3x8mmFeeder02013x8mmFeeder„goldenedition“specializedfor0201and0402Increasedaccuracy/repeatabilityNotapeshutter,eliminatesmechanicalinfluenceonthecomponent3x8mmStandardfeederTapeshutter3x8mmFeeder„Goldenedition“Fixedtaperemovaledge9BulkPackagingProsSmall,nowasteHighcapacityFastrefillConsNewfeedersrequiredNewcomponentreferencenumberPossibledamagetoendterminations10MatrixTrayandWafflePackTheseareusefulforsmallerproductionrunswithcustomizedproductsLargelyusedforIntegratedCircuitpackagesAvailableinsizesof2”x2”andlargerForFinePitchQFPs,BGAs,etc.ForBareDies&CSPs11SuitableforSOICs,SOJs&PLCCsFeederTubesBothflexibleandrigidsticksareavailableforseveralsizesofintegratedcircuitsandothercomponentsAreasonablenumberofdevicescanbehandledineachstickThepartswillremainorientedandprotected,onceloaded12VibratoryFeedersFeederTubesSource:USVIBRA,Inc.13SurfTapeApressure-sensitivestickytapefixedtothebaseofthepunchedplasticcarrierComponentsadherewiththeirback-sidetothestickytapeNocovertapeisusedUsedforbarediesandflipchipsFlipchipshavetobeflippedinsidethefeeder14Source:ChipScaleReviewDirectDieFeeder15SmartFeeders16RetrofitableSmartFeeder-UtilizingRFID17Programming18VisionSystemLOGOModule4–Unit3PickandPlaceProcessStepswww.YS-U.com20PickandPlaceProcessStepsStep1BoardsfromthescreenprintoperationmoveintothePickandPlace•SMTlinesmayutilize1ormorePickandPlacemachinestopopulatePCBs•ThePickandPlaceassembleslargeandsmallSMTcomponentsontotheprintedcircuitboard(PCB)withcorrectorientation,polarityandplacementlocationStep2ComponentsareloadedontothePickandPlaceusingfeedersStep3ThePickandPlaceiscontrolledbysoftware,usingacomputermouseandmonitorStep4AvisionsystemverifiesthePCBisalignedproperlyinthePickandPlace,usingfiducialmarkingsSoftware,monitorandmouseComponentPlacementFeederFiducials21PickandPlaceProcessStepsStep5Nozzles“pickup”and“place”componentsStep6Acameratakesapictureofthecomponentbeingplaced,thispictureiscomparedtothecomponentdescriptioninthemachineprogramStep7ThecomputerchecksforbentleadsandcorrectplacementonthePCBStep8ComponentisplacedonthePCBStep9AbovestepsrepeatedforallcomponentsStep10BoardexitsfromthemachineVisionSystem22PickandPlaceProcessStepsThereare2categoriesofPickandPlaceMachine:FullyAutomaticSemiAutomaticThePickandPlaceprocesssetuphas8stepsthatneedtobefollowed:Step1-AdjustingconveyorrailsStep2-Installationofboardsupports(asrequired)Step3-ComponentSetupStep4-NozzleSetUpStep5-LoadMachineProgramStep6-ComponentReplacementStep7-InspectionStep8-MachineteardownSemiAutomaticFullyAutomatic23ProperAdjustmentSensorStep1–AdjustingConveyorRails1.Pastedboards**fromtheScreenPrintergointothePickandPlaceusingconveyorrails2.RailsarealsousedtotransportPCBsoutofthePickandPlaceaftercomponentsareplaced3.RailsneedtobeadjustedfortheproperwidthandthicknessofthePCB4.Somesystemsdothisautomatically,othersrequireamanualadjustment5.SensorsallowthePCBtostopinthecorrectpositioninthePickandPlacemachineautomatically**ItisimportanttohandlePCBsbytheedges