Solder fluxua hauj lwm raws li lub unsung chemical catalyst nyob rau hauv metallurgical bonding -ib reactive compound uas strips oxide zaj duab xis los ntawm lub hauv paus hlau thaum tib lub sij hawm txo qhov nro ntawm qhov chaw los txhawb kev zoo solder wetting. IPC J-STD-004B kev faib tawm cov txheej txheem faib cov flux rau hauv plaub tsev neeg muaj xws li: Rosin (RO), Resin (RE), Organic (OR), thiab Inorganic (IN), txhua qhov kev ua ub no raug xaiv raws li Low (L), Nruab Nrab (M), lossis High (H), suav nrog cov ntsiab lus halide (0 rau<0.05% or 1 for detectable halides). Getting this wrong doesn't just mean ugly joints-it means boards that fail in the field, corrosion that eats through traces over months, and the kind of reliability nightmares that keep production engineers up at night.
Dab tsi Flux tiag tiag ua (Thiab yog vim li cas nws tseem ceeb tshaj qhov koj xav)
Nov yog qhov hais txog oxidation: nws tshwm sim sai. ceev heev. Lub sijhawm tooj liab pom huab cua ntawm qhov kub siab, koj tab tom sib ntaus sib tua poob. Oxide txheej tsim nyob rau hauv vib nas this ntawm cua sov, thiab molten solder kiag li tsis kam mus rau daim ntawv cog lus rau oxidized nto. Nws tsuas yog pob thiab zaum ntawd, thuam koj.
Flux tawm tsam qhov teeb meem no los ntawm ob lub ces kaum. Ua ntej, cov khoom xyaw nquag-txawm tias yog abietic acid los ntawm cov ntoo thuv resin lossis hluavtaws organic acids- tshuaj yaj oxides uas twb muaj lawm. Qhov thib ob, lub flux tsim ib daim pam tiv thaiv tshaj cov hlau uas tau ntxuav tshiab, thaiv cov pa oxygen los ntawm re- paug rau saum npoo thaum lub qhov rais luv luv thaum cov khoom siv tau ntws.
Qhov tshwm sim ntub dej yog qhov twg flux khwv tau nws khaws cia. Nto nro ib txwm ua rau molten solder kom txo qhov chaw sib cuag, tsim spheres es tsis sib kis. Flux compounds ua rau txo qhov nro no, tso cai rau cov hlau ntws hla cov ntaub qhwv thiab cov khoom ua rau ntawm qhov nrawm mus txog 0.1 txog 0.2 meters ib ob. Yog tsis muaj nws? Koj tau dewetting, txuas txuas txuas, thiab cov pob qij txha tsis tiav uas yuav dhau los kuaj pom tab sis ua tsis tiav hauv kev caij tsheb kauj vab.
Rosin-Raws li Formulations
Pine tsob ntoo resin tau ua kev lag luam hluav taws xob mus rau- mus rau lub hauv paus flux txij thaum ua ntej koj yawg tau muab cov raj nqus tsev vacuum. Muaj ib qho laj thawj rau lub neej ntev li ntawd -rosin ua haujlwm zoo kawg nkaus rau qhov nws yog.
Cov npe R, RMA, thiab RA taug qab rov qab mus rau cov tub rog tshwj xeeb uas kev lag luam thaum kawg tau tsim los ntawm IPC. Plain Rosin (R) muaj qhov ua kom tsawg, tsim nyog rau qhov chaw pristine uas tau ntxuav lub sijhawm dhau los. Rosin Mildly Activated (RMA) ntxiv me me ntawm cov activators -feem ntau cov organic halides- los tswj lub teeb oxidation ntawm cov khoom lag luam raug. Rosin Activated (RA) coj cov phom loj hnyav rau oxidized los yog tawv heev - rau - solder nto.
Ntawm no yog qhov uas tej yam yuav nyuaj. RMA residues technically tsim nyog raws li "tso- nyob rau hauv - qhov chaw" rau ntau daim ntawv thov, txawm hais tias qhov kev xaiv ntawd yeej ib txwm ua tau zoo me ntsis. Cov residues yog me ntsis hygroscopic. Nyob rau hauv ib puag ncig hauv tsev tswj tau siv cov khoom siv hluav taws xob, tej zaum koj yuav zoo. Muab tib lub rooj tsavxwm rau hauv qhov chaw ntug dej hiav txwv nrog 80% av noo, thiab tam sim ntawd cov "benign" residues pib rub cov av noo los ntawm huab cua, tsim txoj hauv kev ua haujlwm thiab ua kom nrawm dua.
RA flux residues kiag li yuav tsum tau muab tshem tawm. Tsis muaj kev zam. Cov activators uas ua rau RA thiaj li ua tau zoo ntawm kev txiav los ntawm oxides nyob twj ywm nruj tom qab txias. Sab laug nyob rau hauv qhov chaw, lawv yuav tua cov kab tooj liab thiab cov khoom txiav tawm lub sijhawm. Isopropyl cawv ntawm 90% + concentration tswj feem ntau RA residues, txawm tias tawv ncauj tsub zuj zuj nyob rau hauv cov khoom yuav xav tau ib yam dab tsi nruj dua.
IPC kev faib tawm rau rosin fluxes khiav los ntawm ROL0 (rosin, kev ua haujlwm qis, xoom halide) txog ROH1 (rosin, siab ua haujlwm, nrog halides). ROL0 flux ua tau raws li qhov yuav tsum tau muaj kev ntseeg tau nruj tshaj plaws -xav tias aerospace, implantable kho mob cov cuab yeej, txhua yam uas qhov chaw tsis ua haujlwm tsis yog kim xwb tab sis yuav muaj kev puas tsuaj loj.
Tsis yog-Hnub: Kev cog lus thiab qhov tseeb
Lub npe ncaj ncees me ntsis yuam kev. "tsawg kawg- huv" lossis "feem ntau-tsis yog-yuav tsum tau- ntxuav" yuav yog qhov tseeb dua, tab sis qhov ntawd tsis yob tawm ntawm tus nplaig heev.
Tsis muaj- cov dej huv huv tau tshwm sim thaum xyoo 1980s raws li cov lus teb rau Montreal Protocol txwv ntawm CFC- raws li cov kuab tshuaj ntxuav. Kev lag luam hluav taws xob tau tsim tag nrho cov txheej txheem ntws los ntawm vapor degreasing nrog chlorofluorocarbons, thiab tam sim ntawd qhov kev xaiv ntawd ploj mus. Ntau dua li nrhiav lwm txoj hauv kev tu, cov tuam txhab tau thawb cov kws tshuaj flux los tsim cov qauv uas tuaj yeem nyob hauv lub rooj tsavxwm.
Txoj hauv kev yooj yim suav nrog cov ntsiab lus ntawm cov khoom txo qis heev-qee zaum qis li 1-2% piv rau 15-25% rau cov tshuaj rosin flux-ua ke nrog cov activators tsim los ua kom tag nrho lawv tus kheej thaum lub sij hawm soldering thermal profile. Thaum txhua yam mus zoo, koj sab laug nrog nyias, inert, tsis-conductive residue uas yuav tsis ua teeb meem.
Thaum txhua yam tsis mus zoo? Qhov ntawd yog ib zaj dab neeg txawv.
Tsis yog- cov dej huv huv yog qhov nkag siab zoo rau cov ntaub ntawv thermal. Cov activators yuav tsum ncav cuag qhov kub thiab txias rau lub sijhawm tshwj xeeb kom tawg tag nrho. Cov cua sov tsis txaus tso cov tshuaj reactive tom qab. Qhov no yog qhov teeb meem tshwj xeeb hauv kev xaiv soldering thiab tes rework, qhov twg cov cua sov profiles tsis muaj kev tswj xyuas tsawg dua li cov reflow ncu.
Muaj qhov qias neeg qias neeg nyob rau hauv siab - kev tsim kev ntseeg siab: ntau lub khw ntxuav lawv tsis muaj - ntxuav flux lawm. IPC-A-610 Chav Kawm 3 qhov yuav tsum tau ua rau lub dav hlau thiab tub rog pawg thawj coj tswj hwm nws rau cov ntawv thov tseem ceeb. Qhov laj thawj yog qhov yooj yim -vim li cas thiaj li pheej hmoo? Dense boards with tight trace spacing and low-standoff components like BGAs create perfect environments for flux residues to trap moisture and cause electrochemical migration.
Tsis muaj - cov khoom seem huv si kuj yog qhov nyuaj rau kev tshem tawm yog tias koj txiav txim siab ntxuav yog tsim nyog. Qhov qis- cov qauv kev ua haujlwm uas ua rau lawv "muaj kev nyab xeeb" tawm hauv qhov chaw kuj tseem ua rau lawv tawv ncauj tiv taus cov kuab tshuaj ntxuav. Koj yuav xav tau cov tshuaj lom neeg nruj heev-acetone, hexane, lossis cov khoom sib xyaw ua ke-thiab cov no coj lawv tus kheej tuav thiab kev txhawj xeeb ib puag ncig.
Dej-Soluble Flux: Lub zog thiab qhov tshwm sim
Yog hais tias rosin yog ib tug scalpel thiab tsis muaj - huv si yog ib tug butter riam, dej -soluble flux yog ib tug chainsaw. Nws ua haujlwm sai, tab sis koj yuav tsum hwm qhov koj ua haujlwm nrog.
Cov organic acid activators hauv dej -soluble flux-feem ntau glycol-raws li citric, lactic, los yog adipic acids- muab tshwj xeeb oxide tshem tawm thiab ntub dej. Rau qhov chaw oxidized hnyav heev, nyuaj-rau- solder metallizations, lossis txhuas- cov txheej txheem dawb uas qhov kub siab dua ua kom oxidation, dej- soluble feem ntau ua tau zoo dua lwm txoj kev xaiv los ntawm cov npoo dav.
Lub flip sab yog yuav tsum tau, tag nrho, sai tu. Cov dej- cov dej soluble residues yog hygroscopic heev thiab corrosive heev thaum ntub. Tso lawv rau ntawm lub rooj tsavxwm hmo ntuj hauv qhov chaw ntub dej, thiab koj yuav pom pom kev xeb thaum sawv ntxov. Lub qhov rais ntxuav yog ntsuas hauv cov xuab moos, tsis yog hnub.
Kev ntxuav nws tus kheej yog ncaj nraim - dej deionized, feem ntau nrog cov tshuaj ntxiv me me, hauv cov tshuaj tsuag lossis cov tshuab immersion. Ultrasonic agitation pab dislodge residues nyob rau hauv lub Cheebtsam. Qhov tseem ceeb tshaj plaws yog kev ncaj ncees. Kev tu ib nrab tuaj yeem ua rau muaj qhov tsis zoo los ntawm kev faib cov khoom paug mus rau hauv nyuaj dua - mus rau - mus txog thaj chaw yam tsis tau tshem tawm tag nrho.
Ib qho feem ntau - tsis pom kev xav: dej- cov dej nyob hauv cov dej soluble yog cov khoom siv hluav taws xob thaum ntub dej. Qhov no txhais tau tias kev ntxuav yuav tsum tau ua raws li kev ziab kom tiav ua ntej kev kuaj hluav taws xob. High-cov ntaub ntawv ntom ntom nrog qhov muag tsis pom los yog hauv qab- cov khoom uas raug tshem tawm tuaj yeem khaws cov dej noo hauv qhov nyuaj- mus rau- qhov chaw qhuav, yuav tsum tau ncua sij hawm kom qhuav los yog lub tshuab nqus tsev vacuum.
Lead-Txhua yam hloov pauv dawb (yuav luag)
Qhov kev siv RoHS xyoo 2006 tau yuam kom rov xav txog qhov tseem ceeb ntawm kev siv tshuaj lom neeg thoob plaws hauv kev lag luam. Ib txwm tin -lead eutectic (63/37 lossis 60/40) melts ntawm 183℃. SAC305-cov hlau lead tseem ceeb-dawb alloy-yuav tsum tau 217-220℃kom ntws zoo. Qhov sib txawv ntawm 35-40℃cascades los ntawm txhua yam ntawm cov txheej txheem soldering.
Cov kub siab dua txhais tau tias ceev oxidation tus nqi, thov kom muaj ntau yam flux formulations kom ceev. Tab sis qhov kub siab dua kuj ua rau cov dej ntws tawm sai dua, txo cov qhov rais tiv thaiv thaum lub sij hawm soldering.
Flux manufacturers teb nrog kev hloov kho kom zoo rau cov kev xav tau ntau dua thermal, tab sis cov npoo ntawm qhov yuam kev poob qis heev.
Lead- dawb solder kuj ntub dej qeeb dua li cov khoom siv lead ua. Lub lauj kaub kub kub, lub sij hawm sib cuag, thiab preheat profiles uas ua haujlwm zoo rau Sn63/Pb37 tsim cov pob qij txha txias thiab tsis txaus lub qhov sau nrog cov hlau lead-dawb alloys. Flux kev ua haujlwm dhau los ua qhov tseem ceeb tshaj los them rau qhov kev txwv tsis pub ntub dej ntawm cov tin-silver- tooj liab metallurgy.
IPC-J-STD-001 cov cai yuav tsis yooj yim dua. Chav kawm 3 cov rooj sib txoos tseem xav tau qhov kev ntseeg tau zoo ib yam - sib cav ntau dua, txij li cov hlau lead- cov pob qij txha pub dawb muaj qhov cuam tshuam ntau dua rau cov tin whisker loj hlob thiab thermomechanical qaug zog. Kev xaiv Flux rau lub hom phiaj-cov hlau lead tseem ceeb- cov rooj sib txoos dawb yuav tsum tau ua tib zoo saib xyuas rau ob qho tib si tam sim ntawd soldering kev ua tau zoo thiab kev coj tus cwj pwm mus ntev.
Cov txheej txheem xaiv tswv yim
Kev ntsuam xyuas qhov chaw saum npoo
Pib nrog dab tsi koj nyob nraum soldering. Fresh OSP-cov boards tiav nrog cov khoom tsim tawm tsis ntev los no? Txawm tias me me ROL0 flux yuav ua haujlwm. Cov khoom lag luam muaj hnub nyoog nrog pom tarnishing ntawm cov khoom coj? Koj yuav xav tau ib yam dab tsi nrog ntau tom. ENIG thiab immersion silver nto feem ntau solder yooj yim dua li liab qab tooj liab los yog tin tiav, uas cuam tshuam rau kev ua haujlwm ntawm flux.
Muaj peev xwm ntxuav tau
Ua siab ncaj txog koj qhov kev tu vaj tse. Yog tias koj tsis muaj lub tshuab nqus dej inline thiab tsis npaj yuav ntxiv ib qho, dej -soluble flux tej zaum tsis yog koj cov lus teb txawm tias nws cov dej ntub dej zoo dua. Yog tias koj tus txheej txheem xav tau tom qab- solder tu rau conformal txheej adhesion, tsis muaj -clean flux tsim ib qho kev sib tw ntxuav ntxiv uas koj tuaj yeem zam los ntawm kev siv cov tshuaj ntxuav kom yooj yim dua.
Xaus -Siv ib puag ncig
Cov khoom siv hluav taws xob siv hluav taws xob ua haujlwm hauv huab cua-cov chaw tswj hwm muaj qhov xav tau kev ntseeg siab sib txawv dua li kev tswj hwm kev lag luam hauv steel zeb lossis cov khoom siv avionics ntawm 40,000 ko taw. Cov chav kawm IPC muaj nyob rau qhov laj thawj zoo. Chav Kawm 1 tso cai rau ntau lub latitude; Chav Kawm 3 xav tau kev xaiv kev saib xyuas.
Txheej Txheem Tswj Peev Xwm
Tsis muaj- cov fluxes huv yuav tsum nruj dua thermal profile tswj dua li rosin los yog dej- lwm txoj kev soluble. Tes soldering thiab xaiv soldering ua haujlwm inherently muaj ntau qhov sib txawv dua li cov txheej txheem reflow. Yog tias koj tus txheej txheem tswj tau raug txwv, kev zam txim ntau dua ntawm cov tshuaj tiv thaiv kab mob txo qis txawm tias nws txhais tau tias ntxiv cov kauj ruam tu.
Residue Teeb meem Koj yuav ntsib tiag tiag
Dawb residue formationsFeem ntau qhia tau tias tsis muaj kev ua kom flux txaus lossis kev tu tsis tiav. Cov tebchaw yeej tsis muaj kev cuam tshuam tag nrho thaum lub sij hawm soldering, tawm hauv unreacted activators uas tom qab nqus noo noo thiab pom. Cov kuab tshuaj muaj zog nrog cov neeg kho tshuab agitation feem ntau daws qhov no, tab sis rov tshwm sim cov teeb meem dawb rov qab taw tes rau cov txheej txheem teeb meem es tsis yog kev tu yooj yim.
Dendritic kev loj hlobyog tus txaus ntshai. Cov kab mob ionic ntxiv rau cov dej noo ntxiv rau cov khoom siv hluav taws xob sib npaug sib npaug electrochemical migration-cov khoom siv hlau nplaum loj hlob ntawm cov kab mus txog thaum lawv ua rau luv luv. Nov yog lub sijhawm- nyob ntawm qhov ua tsis tiav uas yuav tsis tshwm sim rau lub hlis lossis xyoo hauv kev ua haujlwm. Lub hauv paus ua rau yog yuav luag ib txwm tsis txaus tu ntawm active flux residues.
Txheej adhesion tsis ua haujlwmtshwm sim thaum conformal coatings nqa los ntawm cov laug cam vim muaj paug nyob rau hauv lawv. Txawm tias "tsis muaj- huv" cov khoom seem tuaj yeem cuam tshuam nrog cov txheej txheem adhesion, uas yog vim li cas aerospace specifications feem ntau tswj xyuas tsis hais hom flux thaum yuav tsum tau txheej txheej.
Corrosion nyob rau hauv cov khoomtshwj xeeb tshaj yog insidious vim nws pom tsis tau txog thaum ua haujlwm tsis ua haujlwm. Cov kab mob hnyav heev uas nyob hauv qab qis - cov khoom sib tsoo tawm tsam kev txiav tawm thiab cov ntaub qhwv lub sijhawm. Thaum cov tsos mob tshwm sim, qhov kev puas tsuaj yog dav.
IPC Classification System
Kev nkag siab txog J-STD-004B kev xaiv yuav txuag tau qhov tsis meej pem. Plaub tus lej cim encode txhua yam koj xav paub:
Thawj ob tsab ntawv txheeb xyuas muaj pes tsawg leeg: RO rau rosin, RE rau hluavtaws cob, LOSSIS rau cov organic acids, IN rau cov tshuaj inorganic.
Tsab ntawv tom ntej no qhia txog qib kev ua haujlwm: L rau qis, M rau nruab nrab, H rau siab.
Tus lej kawg qhia cov ntsiab lus halide: 0 txhais tau tias qis dua qhov kev txwv tsis pub muaj (<0.05%), 1 means detectable halides present.
Yog li ROL0 yog rosin-raws li, qis- ua haujlwm, halide-dawb flux- qhov kev faib tawm zoo tshaj plaws. ORM1 yog cov organic-acid-raws li, nruab nrab- kev ua haujlwm flux nrog halides- hnyav dua thiab xav tau kev saib xyuas tu.
Qib kev ua ub no cuam tshuam nrog kev tu kom huv. L0 thiab L1 fluxes feem ntau tsim nyog raws li kev tawm mus - hauv - qhov chaw rau Class 1 thiab 2 daim ntawv thov. M0 thiab M1 yog ciam teb- lees txais tsis huv hauv qee qhov xwm txheej, pom zoo kom ntxuav hauv lwm tus. H- theem fluxes yuav luag txhua zaus yuav tsum tau ntxuav txawm tias muaj pes tsawg leeg.
Cov neeg siv khoom tshwj xeeb tuaj yeem hais txog cov kev faib tawm ncaj qha. Ib nqe lus zoo li "Siv ROL0 lossis REL0 flux nkaus xwb" tshem tawm 90% ntawm cov khoom muaj tab sis ua kom muaj kev ntseeg siab ntev ntev -.
Cov ntawv khaws cia thiab tuav
Flux muaj lub neej txee. Paste flux tshwj xeeb. Cov activators maj mam hnov mob nrog cov rosin lossis resin cov cab kuj txawm nyob hauv chav tsev kub, maj mam txo cov haujlwm. Feem ntau cov tuam txhab tau teev tseg 6-12 lub hlis txee lub neej nyob rau hauv tub yees, luv luv ntawm chav tsev kub.
Kev raug rau cov av noo degrades dej-soluble flux formulations tshwj xeeb. Khaws cov ntim ntim kaw thaum tsis siv. Kev kis kab mob los ntawm cov txhuam hniav qias neeg lossis cov ntawv thov tuaj yeem qhia cov khoom siv lossis cov ionic compounds uas cuam tshuam rau kev ua haujlwm lossis tawm cov khoom seem.
Flux cwjmem yooj yim tab sis muaj lawv tus kheej quirks. Cov lus qhia muaj peev xwm qhuav tawm ntawm kev siv, xav tau priming ua ntej thov. Hla -kev sib kis ntawm cov hom flux los ntawm cov neeg thov kev sib koom yog ib qho kev xav tsis thoob thiab muaj teeb meem xav tsis thoob.
Qhov kub thiab txias cuam tshuam rau viscosity thiab kis tus cwj pwm. Cov dej txias los ntawm lub tub yees cia yuav tsis ntws zoo. Tso cai rau cov khoom hauv tub yees kom sib npaug rau hauv chav tsev kub ua ntej siv -feem ntau yog ib teev los yog li ntawd rau muab tshuaj txhuam.
Dab tsi tsis muaj leej twg qhia koj txog Flux Fumes
Rosin flux haus luam yeeb yog ib qho kev lees paub txog kev phom sij. Cov abietic acid vapors tso tawm thaum lub sij hawm soldering ua rau ua pa rhiab heev rau qee tus neeg, ua rau kev ua haujlwm hawb pob uas tuaj yeem tshwm sim txawm tias tom qab raug tso tseg. Kev tso pa tawm hauv zos ntawm qhov chaw nres tsheb soldering tsis yog xaiv rau qhov chaw tsim khoom.
Hobbyists feem ntau tsis quav ntsej qhov no vim tias lawv tsuas yog siv qee zaus, thiab qhov tshwm sim zoo li tsawg. Qhov ntawd yog qhov zoo rau kev siv qee zaus, tab sis ib tus neeg ua haujlwm tsis tu ncua yuav tsum teeb tsa qhov tsawg kawg nkaus tus kiv cua me me kom coj cov pa tawm ntawm qhov chaw ua pa. Lub hom phiaj- ua fume extractors nrog pom zoo dua.
Dej- cov pa taws uas muaj kuab lom tuaj yeem ua rau khaus khaus vim muaj cov organic acids. Qee qhov tsis muaj - cov qauv huv huv tau thov qis qis qis, txawm tias qhov no txawv ntawm cov khoom lag luam.
Txoj cai flux ua rau soldering yooj yim. Qhov tsis ncaj ncees lawm ua rau nws ua tsis tau. Txhua yam nyob rau hauv nruab nrab yog kev kawm paub-qee zaus kev kawm kim heev thaum qhov kev ua tsis tau zoo pib dov. Siv sijhawm ua ntej kom phim cov yam ntxwv ntawm cov flux rau koj cov txheej txheem tshwj xeeb, cov khoom siv, thiab qhov kawg- siv cov kev cai yuav tiv thaiv cov teeb meem uas tsis tshwm sim kom txog thaum cov khoom nyob rau hauv cov neeg siv khoom txhais tes thiab koj tab tom sim piav qhia vim li cas cov pob qij txha uas zoo li zoo tag nrho yog tam sim ntawd ua tsis tiav.
