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1、迴焊爐溫度設(shè)定廠務(wù)處劉年桂2013/Nov/07Contents爐膛設(shè)計Profile四個區(qū)間說明融錫狀態(tài)PWI高溫影響CTE測溫線埋設(shè)爐溫升溫圖型說明速度與爐膛加熱計算模擬InsideofOven(加熱爐膛內(nèi)部)HeatingIntheovenUseVitronicsXPM21030ReflowprofileAngle-chipforCapacitortc1–smallSMDΔT:thesmallerthemass,thehotteritgets!tc1–mediumSMDtc3–largeSMDTimeTemp.230°C250°Ctc1–sm
2、allSMDtc1–mediumSMDtc3–largeSMD20°C20°CSmallSnAgCuProcessWindowTooHot!TooCold!Peak:230–250°Ctc1–255Ctc2–235°Ctc3–225°CHighTemperatureProfilesforleadfreereflowsolderingHightemp.reflowprofilesareoftenrecommendedtosolderleadfreeassemblies.Peaktemperaturesupto260°Carewritteninthel
3、iterature.Thisextremehightemperaturesmaydamagecomponents,PCBlaminateandinfluencesolderjointreliabilityandshape.SnPbSnAgCuSnAgCuTmax215°CTmax235°CTmax260°CComponent:ChipC1206AgPdBoard:NiAuPictures:Zollner,ZandtLeadFreeReflowProcessConcernsLeadFreeReflowProcessConcerns:Component
4、Damage225oC250oCVaporpressureinELCOPictures:PhilipsLFPeak:230°C–250°C??LeadFreeReflowProcessConcerns:ComponentDamage225oC255oCPictures:PhilipsLFPeak:230°C–250°C??240oC270oCDeformationofthermo-plasticcomponentbodiesLeadFreeReflowProcessConcerns:ComponentDamagePictures:JabilLFPe
5、ak:230°C–250°C??LeadFreeReflowProcessConcerns:OpenorNearOpenJointsResultofboardwarpageandcomponentbulgingduetohightemperaturePicture:PhilipsTheriskofmicrocracksincreasewiththedistancetothecenter.Ashigherthetemperature,ashighertheexpansionthermalexpansion(CTE)Highertemperaturei
6、ncreasesmechanicalstressonsolderjointsFailuretoproperlymountTCswillresultinanunwanted?T!ReflowMachineProfiling–TheMostImportantStep!X???SurfacemeasurementBGAballmeasurementClassicalTemperatureProfileofaHotflow2/24Gradients?deltaT?PCBPBGASpeed:1m/min?T=5,8°C!ThermalManagement:F
7、lexibleProfiling–ClassicalSoak(1)HighPlateauTemperaturemaydamagePCBlaminateThermalManagement:FlexibleProfiling–ClassicalSoak(2)ClassicalTemperatureProfileofaHotflow2/24Gradients?deltaT?PCBPBGASpeed:1m/min?T=4,5°C!RaisingPreheattempcanreduce?TLinearTemperatureProfileofaHotflow2
8、/24Gradients?deltaT?PCBPBGARunningjustalinearprofileonsuchahi
