FlashSoldering_Diode_Laser

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1、“FlashSoldering”–ANewOpportunityforDiodeLasersDavidW.SteinmeiermicroJoiningSolutionsBackground–Theelectronicsindustryeffectivelyusesmassreflowsolderingtechniquestobondthemajorityofthrough-holeandsurfacemountcomponentstotheirprintedcircuitboard(PCB)assemblies.However,somet

2、emperaturesensitiveelectroniccomponentscannottoleratethehightemperaturepeakof230°Cforoneminutethatistypicallyencounteredinthemassreflowsolderingprocesswithoutsufferingdamage.Thesecomponentsaresolderedoff-lineusinghandorothersemi-automatedsolderingtechniques.Thisprocessisc

3、ommonlyknownas“OddFormSoldering”or“SelectiveSoldering”andconstitutesasmuchas10%ofallelectronicassemblywork.Handsolderingisslowandhighlydependentonoperatorskillleveltoachieveagoodsolderjoint.Attemptstousesemi-automatedformsofselectivesolderinghavebeenpartiallysuccessful.Se

4、mi-automatedselectivesolderingtechniquesincludehotbar,thecommonsolderingiron,andmicro-flame.Allthreeheatsourcesrequireintimatecontactwiththecomponentstocreateasolderjoint.Theseheatsourcesaretypicallypairedwithasolderwirefeedsystemforcontrollingthewiresolderfeedrate.Hotbar

5、reflowsolderingutilizesatemperaturecontrolledmetalheatingelementthatcanbepulsedtothedesiredreflowsolderingtemperatureormaintainedataconstanttemperature.Hotbarreflowsolderingsuffersfromseveralmajordrawbackswhichincludemechanicaldeformationoftheelectroniccomponentsurfaceand

6、reducedthermaltransferduetowarpingandfluxbuildupontheheatingelementsurface.Insomecases,thehotbarcontactsurfacemustbecleanedasoftenasevery500to1,000cycles.Thesolderingironalsousesametalheatingelementforaconstanttemperatureheatsource.Solderintheformofsolderwireishandorsemi-

7、automaticallyfeedintothejointarea.Topreventareductioninheattransfer,thesolderingironheatingelementortipmustbeconstantlywipedbyamechanicalscrubbingmechanismtoremovefluxandsolderoxidebuildup.Thisrepeatedoxidationremovalprocesseventuallyresultsinthereplacementoftheheatingele

8、ment.Micro-flameheatingemploysaminiaturegasfeedflametocreatethenecessarysolderingheat.Micro-flam