lead free-无铅焊接规范

Lead-FreeFR-4Specs:FactsandFictionByDouglasJ.Sober Wednesday,28June2006JustintimeforJuly1,whatyouneedtoknowaboutIPC-4101B-whatitdoesandwhatitdoesn'tdo.Notsincethe1997cancellationofMIL-S-13949Hhastheelectronicsindustrybeeninsuchafervoraboutabasematerialspecification.Remembertheproclamations?NoMIL-SPEC!NoQPL!IPC-4101isthereplacement!Planeswillfallfromtheskyandmankindwillceasetoexist!However,thepredictedapocalypsedidnottakeplace.IPC-4101becamethebasematerialsstandardfortheU.S.andmuchoftheworldaswell.IPC-4101anditssubsequentrevision,IPC-4101A,representoneofthemostwidelyusedIPCdocuments.Butwhereasthe"A"revisionwaswrittenandimplementedasanevolutionarysequeltotheoriginal,IPC-4101Bhasbecomealightningrodforattention.Theproposed"B"revisionofIPC-4101,SpecificationforBaseMaterialsforRigidandMultilayerPrintedBoards,containsnewspecificationsheetsdescribingFR-4basematerialsthatarecompatiblewithlead-freeassembly.ThesespecificationsheetsalsooutlinequalificationandperiodicconformancerequirementsnotfoundcurrentlyforFR-4basematerials,includingTd,T260,T288,T300andZ-axisexpansion.Thesespecificationsheetsarelistedherealongwithsomedescriptiveinformation:IPC-4101B/99.HighTgFR-4,inorganicfillers,brominatedflameretardantIPC-4101B/101.LowTgFR-4,inorganicfillers,brominatedflameretardantIPC-4101B/121.LowTgFR-4,nofillers,brominatedflameretardantIPC-4101B/124.HighTgFR-4,nofillers,brominatedflameretardantIPC-4101B/126.VeryhighTg,inorganicfillers,brominatedflameretardantIPC-4101B/129.VeryhighTg,nofillers,brominatedflameretardantFact:Keywordswillbepartofthedocument.IPC-4101Bhasbeenexpandedsignificantlyintermsofthebasematerialgradescovered,especiallyinthegenericfamilycalledFR-4.Theoriginal1997versionofIPC-4101had30specificationsheetsandIPC-4101Bnowhas55.Theorganizationalstructuredevelopedinthe1990shasbeenoverwhelmedbytheinclusionofnewmaterialsoverthepastnineyears.Forexample,the20seriesspecificationnumbers(i.e.,20,21,22andsoforth)weredesignatedforFR-4materials.Whenspecificationsheetnumber29wasreached,FR-4materialsspilledoverintothe90seriesandthenthe100seriesnumbers.Inordertohelpusersmoreeasilyfindmaterialssuitedtotheirneeds,keywordshavebeendevelopedforeachofthe55specificationsheetsinIPC-4101B.Theintentionwastoprovidethetypicalcomposition,application,performancecharacteristicsandmarketforeachbasematerial.IntheelectroniccopiesofIPC-4101B,theuserwillbeabletoconductasearchforthespecificationsheetsbyaspecifickeyword.Forexample,typingintheterm"lead-freeFR-4"willlistspecificationsheetnumbers99,101,121,124,126and129.Fiction:Keywordsarerequirements.Keywordswillprovidetheuserwithaneasyreferenceastothe"normal"useofabasematerialgrade.Alotoftheangstconcerningkeywordsisthattheyareperceivedtobepartoftherequirementsforeachspecificationsheetnumber.Thekeywordsarenotrequirements;theyaresimplyinformation.Currentlyeachspecificationsheetalsohasthefollowinginstructionabovethekeywordssectionintheheader:Keywords:(ForSearchOnly)NOTGradeRequirementsSeeSection7Fiction:Keywordsguaranteeperformance.ThefollowingcanbefoundatthefrontofeachIPCstandard:IPCStandardsandPublicationsaredesignedtoservethepublicinterestthrougheliminatingmisunderstandingsbetweenmanufacturersandpurchasers,facilitatinginterchangeabilityandimprovementofproducts,andassistingthepurchaserinselectingandobtainingwithaminimumdelaytheproperproductforhisparticularneed.Thereisnoguaranteeofperformance.DidmaterialscertifiedtoMIL-S-13949HprovideaguaranteeofperformanceofaradarsysteminanF-16?Manydifferentfactorsbeyondthecontrolofthestandardcaninfluencetheabilitytomanufactureafunctionalboard,assemblyorelectronicpart.ThebestthatcanbesaidisthatmaterialscertifiedtoanIPCstandard,oranyotherstandardforthatmatter,havethebestprobabilityofsuccess.Fiction:Keywordsrestrictmaterialuse.Themainmessageofthekeywordsis"typicaluse."Typicalusedoesnotmean"theonlyuse."Thekeyword"single-sided"mayappearnexttoCEM-1,butthatdoesnotmeanitcan'tbeusedfordouble-sidedboardswithaplatedthrough-holeifsomeonecandoit.Itsimplymeansthetypicaluseissingle-sidedboards.Inaddition,applicationsarenotlimitedtothespecificationsheetswiththatspecifickeyword.Forexample,therearesixspecificationsheetswiththekeyword"lead-freeFR-4."CanotherFR-4materialsbeusedforlead-freeassembly?Yes.CanbasematerialsotherthanFR-4beusedforlead-freeassembly?Yes.IPChasalwaysendorseda"fitnessforuse"philosophywhenitcomestobasematerialsforspecificapplications.ThelistofkeywordsbyspecificationsheetnumberisshowninTable1[PDFformat].Section7ofIPC-4101Bclearlydiscussestheintentofthesekeywords.SeveralexampleshavebeenpresentedtoclarifytheuseofkeywordsasintendedbytheIPCLaminateandPrepregSubcommitteememberswhopreparedthisdocument.MostoftheconcernsaboutIPC-4101Bandtheuseofthekeywordsarefiction.SuppliersandcustomersalikemustutilizeeducationandcommunicationtousethisoranyotherIPCstandardwiththeintentofthesubcommitteeauthors. PCD&MDougSoberisamarketingspecialistforKanekaTexasCorp.,amemberoftheIPCRaymondE.PritchardHallofFameandchairoftheIPCBaseMaterialsCommittee.Hecanbereachedatdsober@kanekatexas.com.