Lub luag haujlwm ntawm reflow soldering hauv SMT ua tshuab

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 solder paste (Solder paste) rau ntawm PCB ncoo thiab mount cov khoom siv SMT nti ua ke, thiab tom qab ntawd siv cov cua kub cua sov ntawm lub qhov cub reflow kom sov lub tin lub paste yog yaj. thiab tsim, thiab thaum kawg ib qho kev sib koom ua ke txhim khu kev qha yog tsim los ntawm kev ua kom txias, thiab cov khoom siv txuas nrog PCB ncoo, uas plays lub luag haujlwm ntawm kev sib txuas ntawm cov tshuab thiab hluav taws xob sib txuas.Cov txheej txheem reflow soldering yog qhov nyuaj thiab muaj ntau yam kev paub.Nws belongs rau ib tug tshiab technology interdisciplinary.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 thawj theem cua sov ntawm cov khoom.Nws lub hom phiaj yog kom sov cov khoom sai sai ntawm chav tsev kub thiab qhib lub solder paste flux.Nws tseem yog kom tsis txhob muaj cov khoom siv hluav taws xob los ntawm cov cua kub ceev ceev thaum lub sij hawm tom ntej ntawm immersion tin.Ib txoj kev cua sov tsim nyog rau kev puas tsuaj.Yog li ntawd, tus nqi cua sov yog ib qho tseem ceeb heev rau cov khoom, thiab nws yuav tsum tau tswj nyob rau hauv ib tug tsim nyog ntau yam.Yog tias nws ceev heev, thermal shock yuav tshwm sim, thiab PCB board thiab cov khoom yuav raug thermal stress, ua rau kev puas tsuaj.Nyob rau tib lub sij hawm, cov kuab tshuaj nyob rau hauv lub solder paste yuav evaporate sai heev vim cua kub ceev.Yog tias nws qeeb dhau lawm, cov kua nplaum nplaum nplaum yuav tsis tuaj yeem ua rau tsis muaj zog, uas yuav cuam tshuam rau qhov zoo ntawm cov khoom.

2. Qhov kub thiab txias tsis tu ncua

Thaj chaw ntsuas kub tas li: Nws lub hom phiaj yog los tswj qhov kub ntawm txhua qhov sib txuas ntawm PCB thiab ncav cuag kev pom zoo kom txo tau qhov sib txawv ntawm qhov sib txawv ntawm cov cheebtsam.Nyob rau theem no, lub sij hawm cua sov ntawm txhua yam yog qhov ntev.Yog vim li cas yog tias cov khoom me me yuav ncav cuag qhov sib npaug ua ntej vim qhov nqus cua sov tsawg, thiab cov khoom loj yuav xav tau sijhawm txaus los ntes cov khoom me me vim qhov nqus cua sov 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 txiav txim ntawm flux, oxides ntawm cov ntaub qhwv, cov khoom siv thiab cov pins yuav raug tshem tawm.Nyob rau tib lub sijhawm, flux tseem yuav tshem tawm cov roj ntawm cov khoom siv thiab cov ntaub qhwv, ua rau thaj tsam ntawm qhov sib tsoo, thiab tiv thaiv cov khoom los ntawm oxidized dua.Tom qab cov theem no dhau lawm, txhua qhov yuav tsum tau khaws cia rau tib yam lossis zoo sib xws, txwv tsis pub yuav muaj qhov tsis zoo vim qhov kub sib txawv ntau dhau.

Qhov kub thiab lub sijhawm ntawm qhov ntsuas kub tsis tu ncua yog nyob ntawm qhov nyuaj ntawm PCB tsim, qhov sib txawv ntawm cov khoom siv thiab cov khoom siv, feem ntau ntawm 120-170 ° C, yog tias PCB yog qhov tshwj xeeb, qhov kub ntawm qhov kub thiab txias tsis tu ncua. yuav tsum tau txiav txim siab nrog lub softening kub ntawm rosin raws li ib tug siv, lub hom phiaj yog kom txo tau lub sij hawm soldering nyob rau hauv lub rov qab-kawg reflow cheeb tsam, qhov kub thiab txias cheeb tsam ntawm peb lub tuam txhab feem ntau yog xaiv ntawm 160 degrees.

3. Reflow cheeb tsam

Lub hom phiaj ntawm cheeb tsam reflow yog ua kom cov tshuaj txhuam hniav mus txog lub xeev molten thiab ntub cov ntaub qhwv rau ntawm cov khoom siv los ua kom sov.

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 yaj.Lub melting point ntawm cov hlau lead solder paste Sn: 63 / Pb: 37 yog 183 ° C, thiab cov hlau lead-free solder paste Sn: 96.5 / Ag: 3 / Cu: Lub melting point ntawm 0.5 yog 217 ° C.Nyob rau hauv cheeb tsam no, cov cua sov muab los ntawm lub rhaub yog feem ntau, thiab lub cub tawg kub yuav tsum tau teem rau siab tshaj plaws, yog li ntawd qhov kub thiab txias ntawm solder paste yuav nce mus rau lub ncov kub sai sai.

Lub ncov kub ntawm qhov reflow soldering nkhaus feem ntau yog txiav txim los ntawm lub melting point ntawm solder paste, lub 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, tsis muaj qhov kub siab tshaj plaws ntawm cov hmoov txhuas muab tshuaj yog feem ntau 230-250 ° C, thiab cov hmoov txhuas txhuas feem ntau yog 210-230 ° C.Yog tias qhov kub siab tshaj plaws yog qis dhau, nws yuav yooj yim ua rau vuam txias thiab tsis txaus ntub ntawm cov pob qij txha;Yog tias nws siab dhau lawm, epoxy resin hom substrates yuav Thiab cov yas feem ntau yog ua rau coking, PCB foaming thiab delamination, thiab nws tseem yuav ua rau kev tsim cov hlau eutectic ntau dhau, ua rau cov pob qij txha tawg, ua rau lub zog vuam, thiab cuam tshuam rau cov khoom siv kho tshuab ntawm cov khoom.

Nws yuav tsum tau muab sau tseg tias cov flux nyob rau hauv lub solder paste nyob rau hauv lub reflow cheeb tsam yuav pab tau los txhawb lub wetting ntawm solder paste thiab solder kawg ntawm cov khoom nyob rau lub sij hawm no, thiab txo qhov nro ntawm lub solder paste.Txawm li cas los xij, vim muaj cov pa oxygen seem thiab hlau nto oxides nyob rau hauv reflow rauv, Kev nce qib ntawm flux ua raws li kev cuam tshuam.

Feem ntau, lub qhov cub hluav taws kub zoo yuav tsum ua kom tau raws li qhov kub ntawm txhua qhov taw tes ntawm PCB 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 tag nrho cov kev ua haujlwm soldering tau ua tiav tiav thaum cov khoom nkag mus rau hauv qhov chaw txias.

4. Qhov chaw txias

Lub hom phiaj ntawm qhov chaw txias yog kom txias sai sai rau cov melted solder paste hais, thiab sai sai tsim cov pob qij txha ci ntsa iab nrog lub arc qeeb thiab cov ntsiab lus tag nrho.Yog li ntawd, ntau lub Hoobkas yuav tswj qhov chaw txias, vim tias nws yog qhov tsim nyog rau kev tsim cov pob qij txha.Feem ntau hais lus, qhov txias txias heev yuav ua rau lub molten solder paste lig dhau lawm kom txias thiab tsis, ua rau tailing, sharpening thiab txawm burrs ntawm cov tsim solder pob qij txha.Cov cua txias tsawg dhau yuav ua rau lub hauv paus ntawm PCB pad nto Cov ntaub ntawv sib xyaw rau hauv cov tshuaj txhuam hniav, uas ua rau cov pob qij txha ntxhib, khoob khoob thiab cov pob qij txha tsaus.Dab tsi ntxiv, tag nrho cov ntawv xov xwm hlau nyob rau ntawm qhov kawg ntawm cov khoom siv yuav yaj hauv cov pob qij txha, ua rau cov khoom kawg ntawm cov khoom tiv thaiv ntub dej los yog tsis zoo soldering.Muaj feem xyuam rau qhov zoo soldering, yog li ib tug zoo txias tus nqi yog ib qho tseem ceeb heev rau solder sib koom tsim.Feem ntau hais lus, cov neeg muab tshuaj txhuam cov khoom lag luam yuav pom zoo kom muaj qhov sib koom ua ke txias ntawm ≥3 ° C / S.

Chengyuan Kev Lag Luam yog ib lub tuam txhab tshwj xeeb hauv kev muab SMT thiab PCBA cov khoom siv ntau lawm.Nws muab cov kev daws teeb meem zoo tshaj plaws rau koj.Nws muaj ntau xyoo ntawm kev tsim khoom thiab kev tshawb fawb.Cov kws tshaj lij kws tshaj lij muab kev taw qhia kev teeb tsa thiab kev pabcuam tomqab muag qhov rooj, kom koj tsis muaj kev txhawj xeeb.