7-1第七讲 SMT表面安装技术(2-缺陷)

5-May-20,1,SMTdefectsandcountermeasureSMT缺陷及防范措施,琵椅锹灼甸朽刹湍持蹈恭戌纪资当倘兑詹黍卡拯辟烫翠仓弹哺酝冬董疽稽7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,2,IdentifySMTdefects,IdentifytheSMTdefectsaccordingtoIPC-A-610(Rev:D)根据IPC-A-610(Rev:D)确定缺陷Thisstandardisacollectionofvisualqualityacceptabilityrequirementsforelectronicassemblies.IPC-A-610是关于电子组装外观质量验收条件要求的文件,才默河潭鼎缓钡瘪胶孔痹觉韧庇撕倘甩趴铡乱吟座州六辰溪点找臂年陌碰7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,3,Majorcontributortodefects缺陷的主要分布,Source:MPMsAusersguidetomorePreciseSMTprinting,襟屈蒜粤向态泼蛀报僚泌积怠痪冕搬咖失菜浩可脊组诌收蜕铜厘勤裔磊耀7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,4,Knowthecommondefect了解常见缺陷类型Analysizethepossiblecause分析可能的原因Countermeasureforthedefects基于以上原因采取的对策,LearningObjectives学习目的,窑拖腆载靴唉迹捉曹渗肿指束檬戎祖瞥历乘蛛十柔德乐扔砷著痘澄验捞赘7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,5,Chipcomponentsstandingonaterminalend(tombstoning).片式元件末端翘起（墓碑）,Tombstoning/立碑,驳矛趣关署混坠唇啮学盏休爆屹炔坎独慎壹罩激船事混居合慎斤鲤诚盾滋7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,6,Countermeasure/对策Mechanism:Surfacetensionincomponentterminalisuneveninreflow.原理:在回流过程中零件两末端的表面张力不均衡.1.Componentterminalheatdistributedunevenly零件两末端受热分布不均衡.Insufficientsoaktime:Reflowprofileoptimization.保温区时间太短:优化回流曲线参数.2.PCBPaddesignissue(thepadsdistanceistoobig):improvePCBpaddesign.PCB焊盘设计问题(焊盘间距太大):改善PCB焊盘设计.,Tombstoning/立碑,漏奢沙恋指昔粹纵学龚挣贫半模杆肋槽手剔栋搐拍妒弯移湿旷普徘神饲靶7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,7,Countermeasure/对策3.Componentterminaloxidizationorcontamination:SolderabilitytestifnecessaryandRTVthedefectmaterial.元件末端氧化或者受污染:根据情况做可焊性实验并且退还缺陷物料.4.Printingmisalignment:adjustprintingmachineparameters.丝印偏位:校正丝印机的参数.5.Placementmisalignment:OptimizetheP/清洗钢网b)Replacetherecycledpastewithfreshone./更换新锡膏c)Printingmachineparameteradjustment./校正丝印机参数2.Poorsolderabilityofcomponentorpad./元件或焊盘可焊性太低Rootcause:a)OlddatecomponentorPCB./陈旧元件或PCB板b)ContaminationoncomponentorPCB./元件或焊盘受污染Action:Purgethematerialforfurtherdisposition./清除来料3.Insufficientfluxvolume:increasefluxsprayrate(wavesolder).助焊剂量不足:增加助焊剂喷射量(波峰焊接)4.Preheatexcess:lowerpreheattemperatureproperly(wavesolder).预热过度:适当降低预热温度(波峰焊)5.Chipwaveorsolderwaveheightislow:properheight(wavesolder).波峰高度过低:调整到适当高度(波峰焊),试独坚褒搽嗅则损芯哨鹤自饭本哦波董唬革端磐欺臣送坛拈腥签曝郸赦琉7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,33,InsufficientSolder/少锡,Insufficientsolder焊锡不足,弯砰沁牲挡搽奥闽浦攘袒烘瞥论双旭变幽西鹰圃绍倦渤捶忙畅堤码改贰护7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,34,InsufficientSolder/少锡,Countermeasure/对策1.Stencilaperturecloggingcauseincompletesolderprinting):Automaticormanualcleanthestencil.钢网孔堵塞导致锡膏不完全印刷:自动或者手工清洗钢网2.Noenoughsolderpastevolume(PasteheightunderLCL):VisualinspectionandCpkcontrol.锡膏量不足(锡膏高度在LCL以下):目检和Cpk控制3.Solderpasteprintmisalignment:Finetuneprintingmachine锡膏印刷偏位:校正丝印机使之最优,4.PoorsolderabilityofcomponentorPCBpad:元件或PCB焊盘可焊性差a)Optimizereflowprofile.优化回流曲线b)Exchangethepoorsolderabilitycomponent.更换掉低可焊性元件5.Excessglueorgluemisalignment:Finetunescreenprint(wavesolder).点胶过多或点胶偏位:优化丝印参数6.Lessflux:Increasethefluxsprayonboardbeforeitpasswavesoldering(wavesolder).助焊剂不足:增加助焊剂的喷射量,敬图锚缔手委受胯春乃设晰侨渣萄阎贺函标獭筹垦键蓄浪瑚妙磊岭苔繁寨7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,35,Solderfilletextendsontothetopofthecomponentbody.焊锡接触元件体,ExcessSolder/多锡,檀缨径塘判倦靖哨醛聘壶彩忿谈策婿臃汐崇虏亡峻纶贡丢陋肉与凳愉奶呼7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,36,ExcessSolder/多锡,Countermeasure/对策1.Excesssolderpaste:锡膏量过多a).SolderpasteheightoutofUCL:Adjustprintingmachinetocontrolthepasteheight.锡膏高度超出UCL:校正丝印机控制锡膏高度b).Nonstandardofstencilapertureopening:standardizethestencilapertureopeningfordifferenttypecomponents.钢网开孔不标准:为不同类型的元件设置相应钢网的开孔标准2.Wavesoldering/波峰焊接a)Lowconveyerramp,longwavesolderingtime:Adjustconveyorrampangleto57degreeandsolderingtimeto35second.传送带角度过小,波峰焊接时间变长:校正传送带角度到57度,焊接时间35秒b)Highpreheattemperaturetodryofftheflux:Accordingtofluxspectocontrolthepreheattemperature,normallythePCBsurfacepreheattemperatureshouldbeunder100oC.高预热温度造成助焊剂过度挥发:按照助焊剂的规格控制预热温度,通常,PCB表面温度一般低于100oC,怂原乱鸟赡牧屁子烙雏镐徊健综益屎上饥双蛙秦赂酚攻戮键窘竖跺鲜膨尊7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,37,WrongOrientation/Polarity反向,极性反,Correctpolarity/正确的极性,Wrongpolarity/极性反,ThismarkisanodeoftantalumcapacitoronPCB.,Thismarkisanodeoftantalumcapacitor.,Correctpolarity/正确的极性,Wrongpolarity/极性反,Thismarkiscathodedirection.,Thismarkiscathodedirection.,WrongPolarity:/极性反,朔抬嘻壹刑扣亥组硒吩棱岳新饮交充亲霹驯幌粒饿豫太望授仕隆侥骨傣忠7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,38,WrongOrientation/Polarity反向,极性反,Correctdirection/正确的方向,WrongOrientation/反向,ThismarkisICsdirection.,ThismarkisICsdirectiononPCB.,WrongOrientation/反向:TheICispopulatedininversedirectiononthePCB./IC被反方向组装在线路板上,巨班氓字赦撑毗狸淑该韧伯丛人蒸坑曹殴埃柔爪贮鲸铝痔兔俗贼润曲烈髓7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-May-20,39,Countermeasure/对策1.Wrongplacementmachineprogram:Checkandcorrectthemachineprogram.贴片机程序错误:检查和更正机器程序2.Manualplacementinreversedirection:手工放置元件错误a)Avoidmanualplacementcomponents避免手工放置元件b)Needspecialinspectionforthemanualplacementpriortoreflow(documentcontrol).炉前需要特别检查那些手工放置的元件(文件控制)3.Disorderedorientationinthetray/reeloftheincomingmaterial:卷装或盘装来料元件的不规则放置a)InspectbeforeloadingittoSMT.上料前检查来料b)Feedbacktovendortotakecorrectiveactions.反馈给供应商采取改善行动,WrongOrientation/Polarity反向,极性反,颊减庐诬涤吭抹息彻锰担蚁剔十吝顾康孰握宇太巩改恳痴也贝然填缝泌诽7-1第七讲SMT表面安装技术(2-缺陷)7-1第七讲SMT表面安装技术(2-缺陷),5-