SMT锡膏印刷培训

1Design.Build.Ship.Service.锡膏印刷培训DocumentTitle:LeanHandBookDocumentNo:GBE-KPO-2-033-00Doc.Revision:02DocumentDate:March26,2008BusinessExcellence22019/8/32TechnologyScreenprinter/丝网印刷机SolderPastePrinting丝网印刷丝印机Chip贴片机多功能贴片机多功能贴片机Chip贴片机回流炉32019/8/33TechnologyDescribingtheStencilPrintingProcess丝网印刷工艺概述42019/8/34Technology15mmminDia.Paste/最小直径15mm的锡膏体Zero‘PrintGap’零印刷间隙Metalsheet/金属平板Openaperture/开孔BasicStencilPrintingProcess/基本丝网印刷工艺52019/8/35TechnologyControlled‘PrintSpeed’控制印刷速度Even‘SqueegeePressure’以及刮刀压力BasicStencilPrintingProcess,cont./基本丝网印刷工艺（续）PasteRolling锡膏滚动62019/8/36TechnologyBoardisloweredundercontrolled‘SeparationSpeed’在“分离速度”控制下，板被分离下来BasicStencilPrintingProcess,cont./基本丝网印刷工艺（续）73-Aug-197TechnologySTENCIL钢网83-Aug-198TechnologyEffectofstencil丝网的影响效果Withagoodstencil优良的丝网•Excellentresults极好的结果•Fewfailures很少的故障•Predictableyields可预知的合格率Withabadstencil不良的丝网•Lotsofstencilwiping需要大量的擦拭•Lotsofbridgesandinsufficientdisposition产生许多的桥连和少锡StencilDesignGuideline:IPC7525丝网设计指导文件：IPC752593-Aug-199TechnologyStencilsConsiderations丝网的关键因素StencilThickness丝网的厚度StencilMaterial丝网的材质Steppedoruniformedthicknessstencil阶梯式的或者同一厚度的丝网StencilMaterialCoefficientofFriction丝网材质的摩擦系数StencilSurfaceRoughness丝网的表面粗糙度StencilHardness/TensileStrength丝网的硬度、抗拉强度FramingTension边框的张力MountingMaterial原料的装配PartialorFull部分的和全部的ApertureSize孔径尺寸ApertureShape&Wall开口外形和内侧的形状ApertureArrangement开口排列ApertureAspectRatio开口的纵横比例AreaRatio面积比ApertureTolerance开口大小的公差ApertureGasketing开口的涂层ApertureLocationTolerance开口的位置公差ThicknessTolerance厚度公差103-Aug-1910TechnologyStencilType丝网的类型1.FullStencil全平面丝网2.PartialStencil(stencilwithmeshborder)局部的丝网•Polyestermesh(tension22-30Newtonspersquarecm)•聚酯型网孔（表面张力在22-30N/cm2之间)•Stainlesssteelmesh(tension30-40Newtonpersquarecm)不锈钢网孔（表面张力在30-40N/cm2之间）1.Framelessstencil无框的丝网•MicroMountfromDEKDEK公司的微小贴装丝网•TECFOILfromTECFOILTECFOIL公司的TECFOIL技术•SMartframefromSMTSMT小巧的外框113-Aug-1911TechnologyStencilFabricationMethods丝网的制作方法1.Chemicaletch化学腐蚀–Singlesideetch单个侧面腐蚀–Dualsideetch双行侧面腐蚀–Etchandelectro-polish蚀刻和电抛光2.Lasercut激光切割–Straightlaser直接光刻–Laserandpolish光刻并抛光3.Electroform电铸成型Stencilsaremanufacturedbythreemainmethods:制造丝网的主要三种方法123-Aug-1912TechnologyWallcharacteristicChemicalEtch化学腐蚀孔内壁的特性133-Aug-1913TechnologyCleaningofstencilWheneverprintingiscompleted,CleanthestencilwithlowlintpapersoakedinIPA.任何时候,只要印刷结束，就要用浸有IPA的无尘纸擦净丝网．Usebrushtoclearpasteinstencilapertureifnecessary.如果需要，用刷子清理丝网开孔．143-Aug-1914TechnologyStencilHandling丝网的使用Handlethestencilwithextremecare.Anydents,crackordamageswillresultinpoorprintquality.移动丝网时，要万分小心．任何破边，破碎，或损坏都将导致糟糕的印刷质量．Alwaysholdthestencilbythealuminumframeanddonotdropanyobjectonthestencilorfoil.保持丝网在铝框中永远处于绷紧状态，并且严禁把东西放在丝网上．Donotsetstencildownonsurfacethatwilldamagethefoilsurface.不要把丝网底部平放其它物体上，那样会损坏金属的表面．152019/8/315TechnologyThePerfectPrint/完美的印刷•Cleanedges/清洁的边缘•Flatontop/顶部平坦•Height=StencilThickness高度=钢网厚度•GoodAlignment/很好地对位•NoFluxBleed...无助焊剂溢出162019/8/316TechnologyPastePrintDefect:Bridging/锡膏印刷缺陷：桥联172019/8/317TechnologyPastePrintDefect:ExcessPrintHeight/锡膏印刷缺陷：高度偏高182019/8/318TechnologyPastePrintDefect:Scooping/锡膏印刷缺陷：塌陷192019/8/319TechnologyIncompletePrint/不完全印刷（少锡）202019/8/320TechnologyPastePrintDefect:Misalignment/锡膏印刷缺陷：偏位212019/8/321TechnologyTailing/锡膏拉尖Acceptable/可接受(Soldersmearorslump10%)锡量减少10%Reject/拒收(Soldersmearorslump10%)锡量减少10%SolderPastePrintQuality/锡膏印刷质量222019/8/322TechnologyPasteClogging锡膏堵塞Acceptable/可接受(pastedeposit90%)焊盘锡量超过90%Reject/拒收(pastedeposit90%)焊盘锡量超过90%SolderPastePrintQuality/锡膏印刷质量232019/8/323TechnologySmearingandSlumping/锡膏塌陷Acceptable/可接受(Soldersmearorslump10%)塌陷小于10%Reject/拒收(Soldersmearorslump10%)塌陷大于10%SolderPastePrintQuality242019/8/324TechnologyMajorcontributortodefects/缺陷的主要分布ComponentPlacement15%ReflowsolderandCleaning15.2%SolderPasteScreening63.8%IncomingComponent5.7%Source:MPM’sAuser’sguidetomorePreciseSMTprinting252019/8/325TechnologyHardware/硬件Software/软件Environment/环境Squeegees/刮刀PrintSpeed/印刷速度Temperature/温度Paste/锡膏Humidity/湿度Stencil/钢网Pressure/压力Tooling/surportpinPrintGap/印刷间隙Board/印刷线路板SeparationSpeed/分离速度FactorsAffectingthePrint/影响印刷的因素262019/8/326TechnologySqueegee/刮刀272019/8/327TechnologySqueegeeType/刮刀类型DiamondedgeTrailingedge‘D’cut282019/8/328TechnologySqueegeeMaterial/刮刀材料Polyurethane/聚亚安酯Composite/合成物•2partpolyurethane•Epoxy/环氧树脂Metal/金属•PlainSteel/平钢•Polished/被抛光•Rolled•Lubricatedsurface–Teflon–Permalex292019/8/329TechnologySqueegee/刮刀Hardness/硬度:30to90durometer(ShoreA)with60to90durometermostused,metal.AttackAngle/接触角度:45to75degreesPressure/压力Parallelism/平行度302019/8/330TechnologyScanpicofrubberandmetalsqueegee,paste,cyberoptics橡胶和金属刮刀，锡膏，影像Scavenging312019/8/331TechnologyPrintParameters/印刷参数•PrintSpeed/印刷速度•SqueegeePressure/刮刀压力•SeparationSpeed/分离速度•PrintGap/印刷间隙•UnderScreenCleanRate/钢网底板清洗频率•PasteDispense/加锡膏•Environment/环境322019/8/332TechnologyTriangulationmethod/三角方法Noteonbeamsplatter连续光梁332019/8/333Technology2DInspection(built-insystem)/二维检测Coverageonpad在焊盘上的覆盖范围Coverageonpadtogetherwithstencilrelease/钢网分离以后的锡膏在焊盘上的覆盖范围34Des