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IPC-7530A

2017-March

GuidelinesforTemperatureProfilingforMassSolderingProcesses(ReflowandWave)

SupersedesIPC-7530

May2001

AninternationalstandarddevelopedbyIPC

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ThePrinciplesofStandardization

InMay1995theIPC’sTechnicalActivitiesExecutiveCommittee(TAEC)adoptedPrinciplesofStandardizationasaguidingprincipleofIPC’sstandardizationefforts.

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ShowrelationshiptoDesignforManufacturability(DFM)andDesignfortheEnvironment(DFE)

Minimizetimetomarket

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Notice IPCStandardsandPublicationsaredesignedtoservethepublicinterestthrougheliminatingmis-understandingsbetweenmanufacturersandpurchasers,facilitatinginterchangeabilityandimprove-mentofproducts,andassistingthepurchaserinselectingandobtainingwithminimumdelaytheproperproductforhisparticularneed.ExistenceofsuchStandardsandPublicationsshallnotinanyrespectprecludeanymemberornonmemberofIPCfrommanufacturingorsellingproductsnotconformingtosuchStandardsandPublication,norshalltheexistenceofsuchStandardsandPublicationsprecludetheirvoluntaryusebythoseotherthanIPCmembers,whetherthestandardistobeusedeitherdomesticallyorinternationally.

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IPC-7530A

GuidelinesforTemperatureProfilingforMassSolderingProcesses(ReflowandWave)

DevelopedbytheThermalProfilingGuideTaskGroup(5-22h)oftheAssembly&JoiningCommittee(5-20)ofIPC

Supersedes:

IPC-7530-May2001

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Usersofthisstandardareencouragedtoparticipateinthedevelopmentoffuturerevisions.

Contact:

IPC

3000LakesideDrive,Suite105NBannockburn,Illinois

60015-1219

Tel847615.7100

Fax847615.7105

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Acknowledgment

Anydocumentinvolvingacomplextechnologydrawsmaterialfromavastnumberofsourcesacrossmanycontinents.WhiletheprincipalmembersoftheThermalProfilingGuideTaskGroup(5-22h)oftheAssembly&JoiningCommittee(5-20)areshownbelow,itisnotpossibletoincludeallofthosewhoassistedintheevolutionofthisstandard.Toeachofthem,themembersoftheIPCextendtheirgratitude.

Assembly&JoiningCommittee

ViceChair

KarenA.Tellefsen

AlphaAddemblySolutions

Co-ChairsDanielL.Foster

MissileDefenseAgency

LeoP.LambertEPTACCorporation

ThermalProfilingGuideTaskGroup

Chair

RayPrasad

RayPrasadConsultancyGroup

ViceChairRobertRowland

AxiomElectronics,LLC

TechnicalLiaisonoftheIPCBoardofDirectors

BobNeves

Microtek(Changzhou)Laboratories

ThermalProfilingGuideTaskGroup

WallaceAbles,DellInc.

HeribertoAlanis,TheChamberlainGroup,Inc.

DudiAmir,IntelCorporationRaiyoAspandiar,IntelCorporationPaulAusten,ElectronicControls

DesignInc.

FrederickBeltran,L-3Communications

ErikBjerke,BAESystems

GeraldLeslieBogert,BechtelPlantMachinery,Inc.

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MumtazBora,PeregrineSemiconductor

LanceBrack,RaytheonMissileSystems

DockBrown,DfRSolutionsRichBurke,FlukeProcess

Instruments

LuisBustamante,GrupoChamberlainEricCarmden,Foresite,Inc.

AlejandroCruz,ACMEInc.

JamesDaggett,RaytheonCompanyGerjanDiepstraten,VitronicsSoltecMiguelDominguez,Continental

TemicSAdeCV

GerdFischer,NASAGoddardSpaceFlightCenter

TimGallagher,BAESystemsOgnyanGeorgiev,Centillion

ElectronicsLtd.

ConstantinoGonzalez,ACMETraining&Consulting

GastonHidalgo,SamsungElectronicsAmerica

MitchellHoltzer,AlphaAssemblySolutions

IfeHsu,IntelCorporation

BruceHughes,AMRDECMS&TEPPT

JennieHwang,H-TechnologiesGroup

RickIodice,RaytheonCompanyPaulJarski,JohnDeereElectronic

Solutions

GildardoJimenez-Mungia,TheChamberlainGroup,Inc.

MichaelJohnson,M/A-COMTechnologySolutions,Inc.

MileaKammer,HoneywellAerospaceLeoLambert,EPTACCorporationKyleLoomis,Kester

UrsulaMarquezdeTino,PlexusCorporation

MichaelMoore,U.S.Army-AMRDEC

MilesMoreau,KICMatthewPark,ZFTRW

RayPrasad,RayPrasadConsultancyGroup

JagadeeshRadhakrishnan,IntelCorporation

IvanRashev,CentillionElectronicsLtd

ChristopherRobbat,RaytheonCompany

RobertRowland,AxiomElectronics,LLC

LuisSaldivar,TheChamberlainGroup,Inc.

KeithSellers,NTS-BaltimoreJoseServinOlivares,Continental

TemicSAdeCV

ChrisSmith,PlexusCorp.

VernSolberg,SolbergTechnicalConsulting

UdoWelzel,RobertBoschGmbH

P.GilWhite

EtienneWitte,AxiomElectronics,LLC

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SpecialRecognition

DudiAmir,IntelCorporationRaiyomandAspandiar,Intel

Corporation

PaulAusten,ElectronicControlsDesignInc.

GeraldLeslieBogert,BechtelPlantMachinery,Inc.

GerdFischer,NASAGoddardSpaceFlightCenter

MitchellHoltzer,AlphaAssemblySolutions

IfeHsu,IntelCorporationJennieHwang,H-Technologies

Group

MichaelJohnson,M/A-COMTechnologySolutions,Inc.

MileaKammer,HoneywellAerospaceLeoLambert,EPTACCorporationUrsulaMarquezdeTino,Plexus

Corporation

RayPrasad,RayPrasadConsultancyGroup

JagadeeshRadhakrishnan,IntelCorporation

RobertRowland,AxiomElectronics,LLC

ChrisSmith,PlexusCorp.

VernSolberg,SolbergTechnicalConsulting

UdoWelzel,RobertBoschGmbH

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TableofContents

SCOPE 1

Purpose 1

Background 1

TermsandDefinitions 1

ThermalProfile 1

Recipe 2

PastyRange 2

RampRate 3

Soak(Dwell) 3

Peak 3

MeltingPoint 3

Liquidus 3

Solidus 3

Eutectic 3

TimeAboveLiquidus(TAL) 3

TrueTAL 4

DeltaT(ProfileorEquipment) 4

PhaseDiagram 4

Superheat 4

Cooldown 4

Preheat 4

Class1RadiantIR-DominantSystems 4

Class2Convection/IRSystems 4

Class3Convection-DominantSystems 4

ProfileZones 4

ReflowProgram 4

LiquidusTimeDelay(LTD) 4

APPLICABLEDOCUMENTS 4

IPC 4

JointIndustryStandards 5

JEDEC 5

CONVECTIONREFLOWPROFILING 5

ThermalProfiles 5

ThermocoupleAttachment 10

PreheatZone 13

SoakZone 13

ReflowZone 13

CoolingZone 13

ThermalProfileforBackwardCompatibility 13

UniqueProfileforEachPWBA 14

Flux 14

MaterialIssues 14

ReflowSoldering 14

TrueTimeAboveLiquidus(TrueTAL) 15

EquipmentSettings 16

ReflowOvenSelection 16

IRvs.Convection 16

HeatingZoneSelection 16

ClearanceHeight,ConveyorBeltType/

WidthandEdge-RailSupport 17

CoverGas 17

Profiling 17

ProductTrackers 17

VAPOR-PHASEREFLOWPROFILING 17

Vapor-PhaseReflow 19

WAVESOLDERINGPROFILING 19

MachineConsiderations 20

ConveyorConsiderations 20

PreheatConsiderations 21

SolderPotConsiderations 21

ProfileDevelopmentSteps 21

DesignforMassWaveSoldering

Considerations 22

SELECTIVESOLDERINGPROFILING 22

SolderPot 22

MachineConsiderations 23

PreheatConsiderations 23

SolderPotandNozzleConsiderations 23

ProfileDevelopmentSteps 23

DesignforManufacturing(DfM)for

SelectiveSoldering 24

ThermocoupleAttachmentforWaveandSelectiveSoldering 24

AlternativestoSelectiveSoldering 25

Paste-in-HoleSoldering 25

LaserSoldering 25

TEMPERATUREPROFILINGTOOLS 26

ProductThermalProfilers 26

ThermalProfilerUsageRecommendations 27

ThermalProfilerSpecifications 27

ThermalBarrier 27

StatisticalProcessControl(SPC) 27

MachineProfilers 27

Purpose 27

MeasurementParameters 28

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MachineVerification 28

ContinuousReal-TimeConvection

OvenProfilers 29

ThermocoupleTypesandSelection 29

ThermocoupleType 29

ThermocoupleWireGauge 29

Insulation 29

WireLength 30

ThermocoupleJunction 30

CalibrationandTest 30

ThermocoupleAttachment 30

High-TemperatureSolder 30

Adhesives 30

Aluminum/CopperTape 30

EmbeddedThermocouple 31

ThermallyConductiveAdhesive 31

MechanicalAttachment 31

TROUBLESHOOTING 31

SolderReflowDefects 31

Voids 31

HeadonPillow(HoP) 32

Bridging 32

SolderBalls 33

ColdSolder/IncompleteSolder 33

SolderBeading(SqueezeBalls) 34

GrainySolder 34

Tombstoning 34

SolderWicking 35

BlowHoles/PinHoles 35

AdditionalRootCausesofDefects 36

SolderJointAccept/RejectCriteria 36

ControlofWaveSolderingDefects 36

Figures

Figure1-1 PhaseDiagramforSnPbSolder 2

Figure1-2 PastyRangeofSACSolder 3

Figure3-1 ThermalProfileSchematic 7

Figure3-2 SnPbProfileWithMultipleThermocouples 8

Figure3-3 SAC305ProfileforaSingle-SidedPWBA(BeltSpeedforSingle-Sided

PWBA24InchesperMinute) 8

Figure3-4 ExampleofaSAC305ProfileforaDouble-SidedBoard(Speed21Inches

perMinute) 9

Figure3-5 ExampleofRamptoPeak(RP)Profile(Left)RamptoSoaktoPeak(RSP)Profile(Right) 9

Figure3-6 LocationsofThermocouplesonaBoardwithLargeandSmallComponents 10

Figure3-7 RecommendedLocationsofThermocouples

onaBGA 10

Figure3-8 FirstExampleofThermocoupleonInnerandOuterRows–DrillingFromBottom

ofBGAandOtherComponents 11

Figure3-9 SecondExampleofThermocoupleonInnerandOuterRows–DrillingFromBottomof

BGAandOtherComponents 12

Figure3-10 CuringProfile 15

Figure3-11 RoleofLiquidusTimeDelay(LTD)in

HeadonPillow 15

Figure3-12 TALvs.TrueTAL 15

Figure4-1 VPSProfileShowingWickingandOpens 18

Figure4-2 ProfileforVPSWithPreheatResemblesConvectionProfile(TimeinMinutes) 18

Figure5-1 Dual-WaveSolderProfile 20

Figure5-2 PeakTopsidePreheatTemperature 21

Figure5-3 MassWaveSolderingThermalProfile

IllustrationforaSingle-WaveSolderPot 21

Figure5-4 MassWaveSolderingThermalProfile

IllustrationforaDual-WaveSolderPot 21

Figure6-1 SelectiveSolderingThermalProfile

IllustrationforSelectiveSoldering 24

Figure6-2 ThermocoupleAttachmentforWaveandSelectiveSoldering 24

Figure7-1 TypicalThermalProfiler,Thermocouples,ThermalBarrierandCarrier 26

Figure7-2 ThermocoupleAttachment

(SolderMethod) 30

Figure7-3 ThermocoupleAttachment

(AdhesiveMethod) 30

Figure7-4 ThermocoupleAttachment(TapeMethod) 30

Figure8-1 ReflowDefects–Voids 31

Figure8-2 ReflowDefects–HeadonPillow 32

Figure8-3 ReflowDefects–Bridging 32

Figure8-4 ReflowDefects–SolderBalls 33

Figure8-5 ReflowDefects–ColdSolder/

IncompleteSolder 33

Figure8-6 ReflowDefects–SolderBeading 34

Figure8-7 ReflowDefects–GrainySolder 34

Figure8-8 ReflowDefects–Tombstoning 34

Figure8-9 ReflowDefects–SolderWicking 35

Figure8-10 ReflowDefects–BlowHoles/PinHoles 35

Tables

Table3-1 ProfileComparisonBetweenSnPb,

SAC305andMixedAlloys 6

Table3-2 ProfileComparisonBetweenSACAlloy,SnBi(Low-Temperature)Alloysand

Resin-ContainingSnBiSolderPastes 7

Table5-1 MassWaveSolderingParameterSummary 22

Table6-1 SelectiveSolderingParameterSummary 24

Table8-1 AdditionalRootCausesofDefectsin

SolderJoints 36

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GuidelinesforTemperatureProfilingforMassSolderingProcesses(ReflowandWave)

SCOPE

Thisstandarddescribesthermalprofileguidelinesandpracticalguidelinestomeetrequirementstoproduceacceptablesol-derjointsinmasssolderingprocesses,includingbutnotlimitedtoreflowandwavesoldering.

Thermalprofileisauniquetemperaturevs.timeplotforeachfullypopulatedprintedwiringboardassembly(PWBA),usingthermocouplesattachedwithhigh-temperaturesolderorcopperoraluminumtapestoselectedrepresentativecomponentsofthePWBAasittravelsatagivenbeltspeed(i.e.,transportspeed)throughvarioustemperaturezonesofanovenorsolder-ingsystem.

PurposeThepurposeofthisstandardistoprovideusefulandpracticalinformationfordevelopingthermalprofilestoproduceacceptableSnPbandPb-freeelectronicsassemblies.Thisstandardisformanagers,designandprocessengineersandtechnicianswhodealwithmasssolderingprocesses.

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BackgroundDuringmasssoldering,itisimportantthatallsolderjointsreachtheminimumsolderingtemperature.Minimumsolderingtemperatureistheminimumtemperaturenecessarytoensuremetallurgicalbondingofthesolderalloyandthebasemetalstobesoldered.Metallurgicalbondingrequiresthatthesurfacestobesolderedandthesolderreachthisminimumsolderingtemperatureforasufficienttimetoallowwettingofthesoldersurfacesandtheformationofalayer(s)ofintermetalliccompound(s)ofsomeofthebasemetal(s)withoneormoreconstituentsofthesolderalloy.

Asapracticalmatter,minimumsolderingtemperatureissomewhat(~25°C)abovetheliquidustemperatureofthesolderalloy.ThesolderjointonagivenPWBAthatisthelasttoreachminimumsolderingtemperature(typicallyonorunderneathoneofthecomponentswiththehighestthermalmass)determinesthetemperatureprofilesettingforagivenPWBAandsol-deringprocess/machine.Developingagoodprofileisabalancingactfortheprocessengineer,whoalsoneedstomakesuresmallerandtemperature-sensitivecomponentsdonotoverheatorbecomedamaged.

Reflowsolderingrequirescontrolledratesofheatingandsubsequentcooling;however,toorapidaheatingratecandamagePWBAsandcomponents.HighcoolingratescanalsodamagecomponentsandresultintemperaturegradientsofsufficientmagnitudetowarpPWBAsandlargercomponentsandalsofracturesolderjoints.Becauseofthis,appropriatetemperatureprofilingisessentialforensuringhigh-qualitysolderjoints.

Eventhoughdifferentproducts,basedontheirthermalmass,requiredifferentamountsofthermalinput,allproductsmustachievetheminimumtemperature(temperatureaboveliquidus)withoutexceedingthemaximumtemperature(withoutdam-agetoanycomponents)withinadefinedtimeperiod(thermalprofile).Thisisthekeyreasonfordevelopingauniqueprofileforeachproduct.

Thermalinputisdeterminedbytemperature/gasflowsettingsineachzone,thenumberofzonesandthebeltspeed,whichstaysthesameineachzone.Establishingminimumtemperature,maximumtemperatureanddurationinazoneensuresfor-mationofintermetallicbondingbetweenthecomponentleadsandtheircorrespondingfootprintorlandpatternsonthosepads.Allcomponents,eventhoughtheirthermalmassesaredifferent,mustmeetthesameminimumandmaximumtem-peraturerequirements.Thisisthebiggestchallengefordevelopingaprofile,sodevelopingathermalprofileforaPWBAwithverylargethermalmasscomponents(e.g.,alargeballgridarray(BGA))andsmallthermalmasscomponents(e.g.,0201orsmallerchipresistorsandcapacitors)isabalancingact.Inaddition,differentheatingandcoolingrateswillhavevariouseffectsonavarietyofdefects,addingmorecomplexitytothebalancingact.Forexample,aslowerheatingratewillhelpreducevoidsinaBGA,butitwillincreasethepotentialforheadonpillow(HoP)inthesameBGA.

TermsandDefinitionsOtherthanthosetermslistedbelow,thedefinitionsoftermsusedinthisstandardareinaccor-dancewithIPC-T-50.

ThermalProfileAuniquetemperaturevs.timeplotforeachfullypopulatedPWBA,usingthermocouplesattachedwithhigh-temperaturesolderorcopperoraluminumtapestoselectedrepresentativecomponentsofthePWBasittravelsatagivenbeltspeedthroughvarioustemperaturezonesofanovenorsolderingsystem.Eachproductrequiresuniqueovensettingsandbeltspeed(recipe)toachievethedesiredprofileonthePWBA.

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Thermalprofilemayalsobeknownasreflowprofile,waveprofile,selectiveprofile,laserprofileorothersolderingprofiles.

RecipeAcombinationofovensettingsandconveyorspeedbasedonthethermalprofileofaproduct.Sometimesalsoknownasreflowprogram.

PastyRangeThesemiliquidstatebetweenliquidusandsolidus,assolderbeginstosolidifybutisnotyetcompletelysolidandalsowhensolderbeginstomeltbutisnotyetcompletelymolten.

Figure1-1showseutectictemperature,superheatandpastyrange.Eutectictemperatureisthelowestmeltingpointpossibleforthealloyandislowerthanthemeltingpointofanyofthemetalsinthealloy.Eventhougheutecticisanalloy,itbehaveslikeametalbecauseithasonlyonemeltingpoint,justlikeametal.Therangecanbeverysmallorverylargedependingonthecompositionofthealloy.AsseeninFigure1-1,eithertotheleftorrightofeutectictemperature,thepastyrangeisverysmall,butitgrowsasthecompositionchangesineitherdirectionwithchangesinSnorPbcontent.

400

700

327oC(621oF)

A

G

H

350

600

300

260oC(500oF)

500

250

210oC–240oC(410oF–464oF)

231oC(448oF)

K400

200

183oC(361oF)

J

300

150

C

200

100

B

50

100

D

10

20 30 40 50 60 70 80 90

F

E

IPC-7530a-1-1

Figure1-1PhaseDiagramforSnPbSolder

A–Liquidsolder

B–Solidsolder

C–EutecticcompositionSN63Pb37

D–Lead

E–Compositionweight%tin

F–Tin

G–Reflowsolderingtemperatures

H–Wavesolderingtemperatures

J–Temperature°C

K–Temperature°F

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Figure1-2showsaSnAgCu(SAC)phasediagram.SinceSACalloyhasanaffinityforcopper,thischangesthetotalcopperpercentagesinthediagram.Thediagramaddressescoppercontentfrom0%to3%byweightontheX-axisandsilvercon-tentfrom0%to8%ontheY-axis.Duetothedissolutionrateofcopperinthisalloycomposition,theanalysishastobeconstantlymonitoredtoverifygoodprocesscontrols.TypicalSACalloysarewithinthezoneof<1%copperand3.5%to4%silver.However,SAC305withsilvercontentof3.5%isthemostcommonlyusedalloy.Itisraretouse4%silverduetohighercostandpotentialreliabilityconcerns.Somemobileapplicationsuse1%silvertoachievebettermechanicalshockandvibrationreliability.

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218

220

222

224

Cu

6

Sn

5

290

270

280

260

Ag

3

Sn

250

240

8

7

6

C

5

A

4

3

2

(Sn)

1

0

0

D

0.4 0.8 1.2 1.6 2.0 2.4 2.8

B

IPC-7530a-1-2

228

226

230

280

290

300

310

Figure1-2PastyRangeofSACSolder

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A–wt%AgB–wt%Cu

C–Compositionregionindustryisusing-Silver3.5%to4%,Copper0.5%to0.7%,remaindertinD–Sn

RampRateThenetchangeintemperaturedividedbytotaltimeinthatzone.

Duringsoldering,theramprateisdifferentindifferentzones(e.g.,preheatzone,soakzone,reflowzoneandcoolingzone).Ramprateisveryhighinthepreheatzoneandisverylowinthesoakzone.

Soak(Dwell)Thetime/temperatureanassemblyisheldataverylowramprateinthereflowsolderingprocesstoallowallcomponentstoreachadesiredstabletemperature.Inareflowoperation,thesoak(dwell)alsoensuresthesolderpasteisfullydriedbeforereachingreflowtemperatures,anditactsasafluxactivationzoneforsolderpastes.

PeakThemaximumallowabletemperatureoftheentireprocess.Aportionofthereflowprocesswherethetempera-tureisraisedsufficientlytocausethesolderpastetoreflow.

MeltingPointThetemperatureatwhichasolderalloystartstobecomeliquid.

LiquidusThelowesttemperatureatwhichanalloyiscompletelyliquid.

SolidusThehighesttemperatureatwhichanalloyiscompletelysolid.

EutecticThetemperatureatwhichsolidusandliquidusarethesame.Thereisnotaplasticrange(materialismal-leablebutnotliquidusorsolidus).

TimeAboveLiquidus(TAL)Thetimeaboveliquidus(TAL)forsolder,expressedatdifferentliquidustemperatures.Thehigherthetemperature,theshortertheTAL.Whenaspecifictemperatureisnotmentioned,TALisassumedtobethetimeabovemeltingpointforsolder.

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Incasesofeutecticalloys,TALandtimeabovemeltingpointarethesame.Incasesofnoneutecticalloys,TALislessthantimeabovemeltingpoint.

TrueTALThesolderjointonaPWBAthatisabovemeltingpointfortheshortestamountoftime,oralsoknownasthedurationoftimewhereallsolderjointsareaboveliquidusofsolder.

TrueTALislessthanTALofcomponent(s)thataresmallerinthermalmass.InthecaseofBGAs,TrueTALislessthanTALofBGAballsontheperiphery,whichareinmoltenconditionlongerthanBGAballsinthecenterofthepackage.

DeltaT(ProfileorEquipment)Thelargesttemperaturedifferencebetweentwoormoremeasurementpointsatagivenpointintime.

PhaseDiagramAnequilibriumdiagramdepictingthermodynamicallydistinctphases,witheachphasepossessingitsowndistinctphysical,mechanicalandelectricalproperties.Inametallurgicalsystem(e.g.,alloy),aphasediagramrep-resentstherelationshipbetweentemperatureandcomposition.

SuperheatThetemperaturedifferencebetweenthepeakreflowtemperatureandtheliquidusofthealloy.Super-heatisgenerallynear25°CinSACPb-freeandnear30°Cto40°CinSnPborlow-temperaturePb-freealloys.

CooldownTheamountoftimenecessaryforaPWBAtoreturntoambienttemperatureafterasolderingoperation.

PreheatThesectionofthesolderingequipmentwhichestablishestheramprateforanassemblybeforesoak.Itisaprofilezonewheretheassemblyisheatedfromroomtemperaturetothebeginningofthesoakzonetemperatureandischaracterizedbytherampslopemeasurement.

Class1RadiantIR-DominantSystemsHeatingaPWBApredominantlybyinfrared(IR)radiationwithlittleornoconvection.

Class2Convection/IRSystemsHeatingaPWBAbyacombinationofIRradiationandconvectioninvaryingratio