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xov xwm

Kev ua haujlwm ntawm reflow vuam hauv SMT txheej txheem

Reflow soldering yog feem ntau siv nto tivthaiv vuam txoj kev hauv SMT kev lag luam.Lwm txoj kev welding yog yoj soldering.Reflow soldering yog tsim rau cov khoom siv chip, thaum yoj soldering yog tsim rau pin hluav taws xob cov khoom.

Reflow soldering kuj tseem yog txheej txheem reflow soldering.Nws lub hauv paus ntsiab lus yog luam tawm lossis txhaj tshuaj kom tsim nyog ntawm cov tshuaj pleev xim rau ntawm PCB ncoo thiab muab tshuaj txhuam cov khoom siv SMT thaj ua haujlwm, tom qab ntawd siv cov cua kub cua sov ntawm lub qhov cub reflow kom yaj cov tshuaj txhuam, thiab thaum kawg tsim ib qho kev txhim khu kev qha. los ntawm kev ua kom txias.Txuas cov khoom siv nrog PCB ncoo los ua lub luag haujlwm ntawm kev sib txuas ntawm cov khoom siv hluav taws xob thiab hluav taws xob.Feem ntau hais lus, reflow soldering yog muab faib ua plaub theem: preheating, qhov kub thiab txias, reflow thiab txias.

 

1. Preheating cheeb tsam

Preheating cheeb tsam: nws yog qhov pib cua sov theem ntawm cov khoom.Nws lub hom phiaj yog kom sov cov khoom nyob rau hauv chav tsev kub sai thiab qhib lub solder paste flux.Nyob rau tib lub sijhawm, nws tseem yog ib txoj hauv kev tsim nyog cua sov kom tsis txhob muaj cua sov tsis zoo ntawm cov khoom uas tshwm sim los ntawm cov cua kub ceev ceev thaum lub sij hawm tom qab tin immersion.Yog li ntawd, qhov cuam tshuam ntawm qhov kub thiab txias ntawm cov khoom yog qhov tseem ceeb heev thiab yuav tsum tau tswj nyob rau hauv qhov tsim nyog.Yog tias nws ceev heev, nws yuav ua rau thermal shock, PCB thiab cov khoom yuav cuam tshuam los ntawm thermal stress thiab ua rau kev puas tsuaj.Nyob rau tib lub sij hawm, cov kuab tshuaj nyob rau hauv lub solder paste yuav volatilize sai heev vim cua kub ceev, uas ua rau splashing thiab tsim ntawm solder hlaws dai.Yog tias nws qeeb dhau lawm, cov kua nplaum nplaum nplaum yuav tsis volatilize tag nrho thiab cuam tshuam rau vuam zoo.

 

2. Qhov kub thiab txias tsis tu ncua

Qhov ntsuas kub tsis tu ncua: nws lub hom phiaj yog kom ruaj khov qhov kub ntawm txhua lub hauv paus ntawm PCB thiab ncav cuag qhov kev pom zoo kom deb li deb tau los txo qhov kub ntawm qhov sib txawv ntawm txhua lub caij.Nyob rau theem no, lub sij hawm cua sov ntawm txhua yam yog qhov ntev, vim hais tias cov khoom me me yuav ncav cuag qhov sib npaug ua ntej vim qhov nqus cua sov tsawg, thiab cov khoom loj xav tau sijhawm txaus los ntes cov khoom me me vim qhov nqus cua kub loj, thiab xyuas kom meej tias cov flux. nyob rau hauv lub solder paste yog tag nrho volatilized.Nyob rau theem no, nyob rau hauv qhov kev ua ntawm flux, lub oxide ntawm lub ncoo, lub pob solder thiab cov khoom siv tus pin yuav raug tshem tawm.Nyob rau tib lub sijhawm, cov flux tseem yuav tshem tawm cov roj stain rau ntawm qhov chaw ntawm cov khoom siv thiab cov ntaub qhwv ntsej, ua rau thaj chaw vuam thiab tiv thaiv cov khoom tiv thaiv los ntawm oxidized dua.Tom qab theem no, tag nrho cov khoom yuav tsum tswj qhov kub thiab txias zoo ib yam, txwv tsis pub vuam tsis zoo yuav tshwm sim vim qhov kub thiab txias sib txawv.

Qhov kub thiab lub sij hawm ntawm qhov kub thiab txias yog nyob ntawm qhov nyuaj ntawm PCB tsim, qhov sib txawv ntawm cov khoom siv thiab cov khoom siv.Nws yog feem ntau xaiv ntawm 120-170 ℃.Yog hais tias PCB yog tshwj xeeb yog complex, qhov kub ntawm qhov kub thiab txias cheeb tsam yuav tsum tau txiav txim nrog rosin softening kub raws li ib tug siv, thiaj li yuav txo tau lub vuam lub sij hawm ntawm reflow cheeb tsam nyob rau hauv lub tom ntej seem.Qhov ntsuas kub tsis tu ncua ntawm peb lub tuam txhab feem ntau xaiv ntawm 160 ℃.

 

3. Reflux cheeb tsam

Lub hom phiaj ntawm cheeb tsam reflow yog ua kom cov nplaum nplaum yaj thiab ntub lub ncoo rau ntawm qhov chaw ntawm lub caij yuav tsum tau welded.

Thaum lub PCB lub rooj tsavxwm nkag mus rau hauv cheeb tsam reflow, qhov kub thiab txias yuav nce sai heev kom cov tshuaj txhuam hniav mus txog lub xeev melting.Lub melting point ntawm txhuas solder paste SN: 63 / Pb: 37 yog 183 ℃, thiab cov hlau lead-free solder paste SN: 96.5/ag: 3 / Cu: 0. Lub melting point ntawm 5 yog 217 ℃.Hauv seem no, lub tshuab cua sov muab cov cua sov tshaj plaws, thiab qhov kub ntawm lub cub tawg yuav tsum tau teem rau qhov siab tshaj plaws, yog li ntawd qhov kub thiab txias ntawm solder paste yuav nce mus rau qhov kub siab tshaj plaws.

Lub ncov kub ntawm reflow soldering nkhaus feem ntau yog txiav txim siab los ntawm lub melting point ntawm solder paste, PCB board thiab kub-resistant kub ntawm cov khoom nws tus kheej.Lub ncov kub ntawm cov khoom nyob rau hauv lub reflow cheeb tsam nws txawv raws li hom ntawm solder paste siv.Feem ntau hais lus, qhov kub siab tshaj plaws ntawm cov hmoov txhuas tsis muaj hmoov txhuas yog feem ntau 230 ~ 250 ℃, thiab cov hmoov txhuas txhuas feem ntau yog 210 ~ 230 ℃.Yog tias qhov kub siab tshaj plaws qis dhau, nws yooj yim los tsim cov vuam txias thiab tsis txaus ntub ntawm cov pob qij txha;Yog tias nws siab dhau lawm, cov epoxy resin hom substrate thiab cov khoom yas yog feem ntau ua rau coking, PCB foaming thiab delamination, thiab tseem yuav ua rau kev tsim cov eutectic hlau sib txuas ntau dhau, ua rau cov khoom sib koom ua ke nkig thiab vuam lub zog tsis muaj zog, cuam tshuam rau cov khoom siv hluav taws xob. mechanical zog ntawm cov khoom.

Nws yuav tsum tau hais tias cov flux nyob rau hauv lub solder paste nyob rau hauv lub reflow cheeb tsam yuav pab tau los txhawb lub wetting ntawm lub solder paste thiab cov khoom welding kawg thiab txo qhov nro ntawm lub solder paste nyob rau lub sij hawm no, tab sis kev nce qib ntawm flux yuav. yuav tsum tau txwv vim yog cov seem oxygen thiab hlau nto oxides nyob rau hauv reflow rauv.

Feem ntau, lub qhov cub kub kub zoo yuav tsum ua kom tau raws li qhov siab tshaj plaws ntawm txhua qhov taw tes ntawm PCB yuav tsum ua kom zoo ib yam li qhov ua tau, thiab qhov sib txawv yuav tsum tsis pub tshaj 10 degrees.Tsuas yog nyob rau hauv txoj kev no peb tuaj yeem xyuas kom meej tias txhua qhov kev ua haujlwm vuam tau ua tiav zoo thaum cov khoom nkag mus rau qhov chaw txias.

 

4. Qhov chaw txias

Lub hom phiaj ntawm qhov chaw txias yog kom ceev cov melted solder paste hais thiab sai sai tsim cov pob qij txha ci ntsa iab nrog qeeb radian thiab tag nrho cov tin.Yog li ntawd, ntau lub Hoobkas yuav tswj qhov chaw txias kom zoo, vim tias nws yog qhov tsim nyog rau kev sib koom ua ke.Feem ntau hais lus, ceev ceev txias yuav ua rau nws lig dhau rau lub molten solder paste kom txias thiab tsis, uas ua rau tailing, sharpening thiab txawm burrs ntawm cov tsim solder sib koom.Cov cua txias tsawg dhau yuav ua rau cov khoom siv hauv paus ntawm PCB ncoo nto sib xyaw ua ke rau hauv cov tshuaj txhuam hniav, ua rau cov khoom sib koom ua ke ntxhib, khoob vuam thiab tsaus muag sib koom ua ke.Dab tsi ntxiv, tag nrho cov ntawv xov xwm hlau ntawm cov khoom siv vuam kawg yuav yaj ntawm qhov sib koom ua ke ntawm txoj haujlwm, ua rau ntub dej tsis kam lossis vuam tsis zoo ntawm cov khoom siv vuam kawg, Nws cuam tshuam rau vuam zoo, yog li qhov txias txias yog qhov tseem ceeb heev rau kev sib koom ua ke. .Feem ntau hais lus, tus neeg muag khoom muab tshuaj txhuam yuav pom zoo rau qhov sib koom ua ke txias txias ≥ 3 ℃ / s.

Chengyuan kev lag luam yog lub tuam txhab tshwj xeeb hauv kev muab cov khoom siv SMT thiab PCBA ntau lawm.Nws muab cov kev daws teeb meem zoo tshaj plaws rau koj.Nws muaj ntau xyoo ntawm kev tsim khoom thiab R & D kev paub.Cov kws tshaj lij tshaj lij muab kev taw qhia kev teeb tsa thiab kev pab cuam tom qab muag ntawm qhov rooj, kom koj tsis muaj kev txhawj xeeb hauv tsev.


Post lub sij hawm: Apr-09-2022