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1、SMT工艺10SMTPROCESSTRAINING10SimaoYangEducationGroupCo.Ltd..YS-U.comIntroduction,TechnologyTrends,AssemblyTypesandSMTComponentTechnologiesModule4–Unit3PlacementConsiderationsandFlexibilitySimaoYangEducationGroupCo.Ltd..YS-U.comConsiderationsforPlacement-BoardSizeEquipmentadjust
2、stomin/maxPCBorpanelsizeforvariousSMTproductsIn-lineconveyorfixturingisutilizedEdgemarginrequirementsmustbedesignedintoPCBorpanelThicknessofPCBisprocessconsiderationWorkenvelopeneedstoincludePCBsize,feeders,andplacementFiducialsonPCBareusedbycameraandcomputerforaccurateplacem
3、ent3ConsiderationsforPlacement-ComponentsEachplacementtoolusuallyhandlesarangeofcomponentsizesVacuumnozzlesizedefinedbydimensionalrangeofcomponentsZ-strokesreferstocomponentmovementinup-downlocationsComponentalignmentonpick-upheadutilizesvisionChips:outline¢roidIC’s:centr
4、oid,individualleads,coplanarity,etc.Componentverificationisdone“onthefly”,checkingforcorrectcomponentvaluesEquipmentdetectsmissingparts4ConsiderationsforPlacement-FeedersComplexityofchangeoveroffeedersisprocessconsiderationNumberoffeedersrequiredequalsnumberofdifferentcompone
5、ntsinbillofmaterialsFeedermustbecompatiblewithcomponentpackagingfromvendorTapecoverpeel-backcapabilitiesbuiltintofeedersEaseofloading-pinlocatorsandelectricalconnectionsaffectprocesstimeOperatorawarenessnecessaryforfeederselectionaccuracy5ComponentPlacementSystemFlexibilityTh
6、ewiderthevarietyofcomponentsamachinecanplace,themoreflexibleitisMostcommonfeedertypes:TapeandreelBulkMatrixtraysandwafflepacksMagazinesortubesVibratoryfeedersSurftapeDirectDiefeeder6TapeandReelPreferredforlargequantityproductionAbilitytoholdlargequantitiesofpartsLowerdowntime
7、requiredforreloadingControlledOrientationandpositionforpartsLotnumbertraceabilitycontrolThetapeisavailableinvaryingwidthsrangingfrom8mmto72mmThecomponentcarrierintapeismadeofpunchedcardboardorthermoformedplasticSuitableforpassivecomponents,discreteactives,SOJs,PLCCs,SOICs,Sta
8、ndardpitchQFPs,BareDies,BGAs&otherSMDsthatdonothavefragileleads7Siem
