Kev ntsuas kub rau SMT reflow soldering

SMT reflow soldering yog txheej txheem tshwj xeeb thiab tseem ceeb hauv kev ua haujlwm thaj. Plaub qhov loj ntawm qhov kub thiab txias ntawm reflow soldering yog preheating cheeb tsam, qhov kub thiab txias cheeb tsam, reflow cheeb tsam thiab txias cheeb tsam. Txhua qhov kub ntawm qhov cua sov theem muaj nws tus kheej qhov tseem ceeb.

1. Preheating cheeb tsam theem

PCBA rau patch processing mus txog qhov reflow qhov cub cua sov ntawm 150 degree los ntawm qhov kub thiab txias nyob rau hauv tsev, thiab cov cua kub tus nqi yog tsawg tshaj li 2 degree / s, uas yog hu ua preheat theem. Lub hom phiaj ntawm lub preheating theem yog evaporate qis melting point hnyav nyob rau hauv lub solder paste. Cov khoom tseem ceeb ntawm flux nyob rau hauv solder paste muaj xws li rosin, activators, viscosity improvers thiab cov kuab tshuaj. Lub luag hauj lwm ntawm cov kuab tshuaj yog tsuas yog ib tug cab kuj ntawm rosin thiab xyuas kom meej lub sij hawm cia ntawm lub solder muab tshuaj txhuam. Thaum lub sij hawm preheating theem, cov kuab tshuaj ntau dhau yuav tsum tau evaporated, tab sis tus nqi cua sov yuav tsum tau tswj. Cov cua kub siab dhau lawm yuav ua rau muaj kev ntxhov siab thermal cuam tshuam rau cov khoom, ua rau cov khoom puas los yog txo cov khoom ua haujlwm thiab kev ua neej. Qhov tom kawg yog qhov teeb meem ntau dua vim tias cov khoom tau raug xa mus rau cov neeg siv khoom. Lwm qhov laj thawj yog vim li cas cov cua kub siab dhau yuav ua rau cov tshuaj txhuam hniav kom tawg, ua rau muaj kev pheej hmoo ntawm luv luv Circuit Court, thiab cov cua kub siab dhau yuav ua rau cov kuab tshuaj evaporate sai heev, uas tuaj yeem yooj yim ua rau cov khoom hlau txaws tawm thiab tin. hlaws kom tshwm.

2. Qhov ntsuas kub tsis tu ncua theem

Tag nrho PCBA board yog maj mam rhuab mus rau 170 degree kom lub Circuit Court board ncav cuag ib tug uniform kub, uas yog hu ua qhov kub thiab txias (soak los yog equilibrium) theem. Lub sijhawm feem ntau yog 70-120s. Nyob rau theem no, qhov kub nce qeeb. Kev teeb tsa ntawm qhov ntsuas kub tsis tu ncua yuav tsum tau xa mus rau cov lus pom zoo ntawm cov khoom siv tshuaj txhuam thiab lub peev xwm kub ntawm PCBA board. Qhov ntsuas kub tsis tu ncua muaj peb txoj haujlwm. Ib qho yog ua kom tag nrho PCBA ncav cuag qhov kub thiab txias thiab txo qhov cuam tshuam thermal cuam tshuam nkag mus rau hauv cheeb tsam reflow, nrog rau lwm yam vuam tsis xws li kev tivthaiv warping, txias vuam ntawm qee qhov loj-ntim, thiab lwm yam.; Lwm qhov tseem ceeb muaj nuj nqi yog Qhov ntawd yog, cov flux nyob rau hauv lub solder paste pib mus rau ib tug active cov tshuaj tiv thaiv, ua rau lub wetting kev kawm ntawm cov nto ntawm lub weldment, thiaj li hais tias lub molten solder yuav zoo ntub dej ntawm lub weldment; Qhov thib peb muaj nuj nqi yog ntxiv volatilize cov kuab tshuaj nyob rau hauv lub flux. Vim qhov tseem ceeb ntawm kev txuag hluav taws xob, lub sijhawm txuag hluav taws xob thiab qhov kub thiab txias yuav tsum tau tswj kom zoo, tsis yog tsuas yog xyuas kom cov flux tuaj yeem ntxuav cov nplaim hluav taws xob zoo, tab sis kuj yuav tsum xyuas kom meej tias cov flux tsis tau noj tag nrho ua ntej mus txog qhov reflow. theem, thiab tuaj yeem qhib tau thaum lub sijhawm reflow. Txhawm rau tiv thaiv re-oxidation.

3. Rov qab thaj tsam theem

Lub PCBA board yog rhuab mus rau lub melting cheeb tsam kom yaj lub solder muab tshuaj txhuam. Lub rooj tsavxwm ncav cuag qhov kub siab tshaj plaws, feem ntau yog 230 degree -245 degree, uas yog hu ua reflow theem. Lub sij hawm saum cov kab kua dej feem ntau yog 30-60 vib nas this. Thaum lub sij hawm reflow theem, qhov kub thiab txias tseem nce ntxiv nyob rau hauv reflow kab, solder paste melts thiab ib tug wetting cov tshuaj tiv thaiv tshwm sim, thiab ib tug intermetallic compound txheej pib tsim, nws thiaj li mus txog lub ncov kub. Qhov kub siab tshaj plaws nyob rau hauv cheeb tsam reflow yog txiav txim los ntawm cov tshuaj muaj pes tsawg leeg ntawm cov tshuaj txhuam hniav, cov yam ntxwv ntawm cov khoom thiab cov khoom siv PCB. Yog tias qhov kub siab tshaj plaws nyob rau hauv qhov chaw reflow siab dhau lawm, lub rooj tsav xwm Circuit Court yuav raug hlawv los yog scorched; Yog tias qhov ntsuas kub siab qis dhau lawm, cov pob qij txha yuav tshwm grey thiab grainy. Yog li ntawd, qhov kub siab tshaj plaws nyob rau hauv cheeb tsam kub no yuav tsum siab txaus kom tso cai rau cov flux kom ua haujlwm tau zoo thiab muaj kev ntub dej zoo, tab sis nws yuav tsum tsis txhob siab txaus ua rau kev puas tsuaj, tawg lossis tawg ntawm cov khoom lossis cov khoom siv hluav taws xob. Lub cheeb tsam reflow yuav tsum tau xav txog tias qhov nce nqes hav ntawm qhov kub thiab txias yuav tsum tsis txhob cuam tshuam cov khoom rau thermal shock. Lub sij hawm rov qab yuav tsum yog luv li sai tau thaum ua kom zoo soldering ntawm cov khoom. Feem ntau, 30-60s yog qhov zoo tshaj plaws. Lub sij hawm reflow ntev ntev thiab kub siab yuav ua rau cov khoom uas yooj yim cuam tshuam los ntawm qhov kub thiab txias, thiab tseem yuav ua rau cov intermetallic compound IMC txheej tuab heev, ua rau cov pob qij txha tawv heev thiab txo qhov qaug zog ntawm cov pob qij txha.

4. Qhov chaw txias txias theem

Cov txheej txheem ntawm qhov kub thiab txias yog hu ua theem cua txias, thiab qhov txias txias yog 3-5 degree /s. Qhov tseem ceeb ntawm lub caij txias yog feem ntau overlooked. Cov txheej txheem ua kom txias zoo kuj tseem ua lub luag haujlwm tseem ceeb hauv qhov kawg ntawm qhov vuam. Cov cua txias ceev dua tuaj yeem ua kom zoo dua microstructure ntawm cov pob qij txha. Hloov cov morphology thiab tis ntawm intermetallic tebchaw thiab txhim kho cov neeg kho tshuab zog ntawm solder alloys. Rau cov hlau lead-dawb soldering nyob rau hauv qhov tseeb ntau lawm, nce qhov cua txias tuaj yeem txo qhov tsis xws luag thiab txhim kho kev ntseeg tau yam tsis muaj kev cuam tshuam rau cov khoom. Txawm li cas los xij, qhov nrawm nrawm dhau los kuj tseem yuav ua rau muaj kev cuam tshuam rau cov khoom, ua rau muaj kev ntxhov siab, ua rau cov pob qij txha ntawm cov khoom ua tsis tiav thaum lub sijhawm siv. Yog li ntawd, reflow soldering yuav tsum muab ib tug zoo txias nkhaus.

Xav paub ntau ntxiv txog Tecoo SMT kev paub:
Lub luag haujlwm tseem ceeb ntawm Kev Ntxiv Nitrogen (N2) ntawm SMT Reflow Soldering