Reflow soldering yog ib kauj ruam tseem ceeb hauv cov txheej txheem SMT.Qhov kub thiab txias profile cuam tshuam nrog reflow yog ib qho tseem ceeb parameter los tswj kom paub meej kev sib txuas ntawm qhov chaw.Cov tsis muaj qee yam tseem yuav cuam tshuam ncaj qha rau qhov kub thiab txias profile xaiv rau cov kauj ruam ntawd hauv cov txheej txheem.
Ntawm cov khoom siv dual-khiav, cov laug cam nrog cov khoom tsim tshiab tau dhau los ntawm qhov chaw kub thiab txias ntawm qhov cub reflow.Cov kauj ruam no yog tsim los kom meej meej tswj lub melting thiab txias ntawm solder kom sau cov pob qij txha.Cov kev hloov pauv kub tseem ceeb cuam tshuam nrog cov reflow profile tuaj yeem muab faib ua plaub theem / cheeb tsam (cov npe hauv qab no thiab piav qhia hauv qab no):
1. Ua kom sov
2. Cov cua kub tsis tu ncua
3. Kub kub
4. Cua txias
1. Preheating cheeb tsam
Lub hom phiaj ntawm cheeb tsam preheat yog kom volatilize qis melting point solvents nyob rau hauv lub solder paste.Cov khoom tseem ceeb ntawm flux nyob rau hauv solder paste muaj xws li resins, activators, viscosity modifiers thiab cov kuab tshuaj.Lub luag haujlwm ntawm cov kuab tshuaj yog feem ntau yog cov cab kuj rau cov resin, nrog rau kev ua haujlwm ntxiv ntawm kev ua kom txaus cia ntawm cov tshuaj txhuam hniav.Lub cheeb tsam preheating yuav tsum tau volatilize cov kuab tshuaj, tab sis qhov kub nce nqes hav yuav tsum tau tswj.Cov cua kub ntau dhau tuaj yeem ua rau thermally ntxhov siab rau cov khoom, uas tuaj yeem ua rau cov khoom puas lossis txo nws cov kev ua haujlwm / lub neej.Lwm qhov kev mob tshwm sim ntawm cov cua kub siab dhau yog tias cov tshuaj txhuam hniav tuaj yeem tawg thiab ua rau luv luv.Qhov no yog tshwj xeeb tshaj yog muaj tseeb rau solder pastes nrog high flux ntsiab lus.
2. Qhov kub thiab txias tsis tu ncua
Kev teeb tsa ntawm thaj chaw kub tsis tu ncua yog tsuas yog tswj tau nyob rau hauv qhov tsis sib xws ntawm cov chaw muab tshuaj txhuam thiab lub peev xwm kub ntawm PCB.Cov theem no muaj ob txoj haujlwm.Thawj yog kom ua tiav qhov ntsuas kub tsis sib xws rau tag nrho PCB pawg thawj coj saib.Qhov no yuav pab txo qhov cuam tshuam ntawm thermal stress nyob rau hauv lub reflow cheeb tsam thiab txwv tsis pub lwm yam soldering tsis xws luag xws li loj ntim tivthaiv nqa.Lwm qhov tseem ceeb ntawm cov theem no yog qhov flux nyob rau hauv lub solder paste pib react aggressively, ua rau lub wettability (thiab lub zog nto) ntawm weldment nto.Qhov no xyuas kom meej tias cov molten solder wets lub soldering nto zoo.Vim yog qhov tseem ceeb ntawm cov txheej txheem no, lub sijhawm so thiab qhov kub thiab txias yuav tsum tau tswj kom zoo kom ntseeg tau tias cov flux huv si huv si thiab cov flux tsis tas yuav tsum tau noj ua ntej nws mus txog cov txheej txheem reflow soldering.Nws yog ib qho tsim nyog yuav tsum khaws cov flux thaum lub sij hawm reflow raws li nws yooj yim rau cov txheej txheem solder wetting thiab tiv thaiv re-oxidation ntawm soldered nto.
3. Qhov kub thiab txias:
Qhov chaw kub kub yog qhov ua tiav melting thiab wetting cov tshuaj tiv thaiv yuav siv qhov chaw uas cov txheej intermetallic pib tsim.Tom qab ncav cuag qhov kub siab tshaj plaws (siab tshaj 217 ° C), qhov kub thiab txias pib poob thiab poob qis hauv qab kab rov qab, tom qab ntawd cov solder solidifies.Ib feem ntawm cov txheej txheem no kuj yuav tsum tau ua tib zoo tswj kom qhov kub thiab txias ramp up thiab down ramps tsis cuam tshuam rau thermal shock.Qhov siab tshaj plaws kub nyob rau hauv lub reflow cheeb tsam yog txiav txim los ntawm qhov kub thiab txias tsis kam ntawm kub-rhiab Cheebtsam ntawm lub PCB.Lub sij hawm nyob rau hauv qhov kub thiab txias cheeb tsam yuav tsum luv li sai tau los xyuas kom meej tias lub Cheebtsam weld zoo, tab sis tsis ntev li ntawd lub intermetallic txheej yuav thicker.Lub sijhawm zoo tshaj plaws hauv cheeb tsam no feem ntau yog 30-60 vib nas this.
4. Qhov chaw txias:
Raws li ib feem ntawm tag nrho cov txheej txheem reflow soldering, qhov tseem ceeb ntawm qhov chaw txias yog feem ntau overlooked.Txoj kev ua kom txias zoo kuj tseem ua lub luag haujlwm tseem ceeb hauv qhov kawg ntawm qhov vuam.Ib tug zoo solder sib koom yuav tsum kaj thiab tiaj tus.Yog tias qhov kev ua kom txias tsis zoo, ntau yam teeb meem yuav tshwm sim, xws li kev nce qib, cov pob qij txha tsaus, tsis sib xws ntawm qhov sib koom ua ke thiab thickening ntawm intermetallic compound txheej.Yog li ntawd, reflow soldering yuav tsum muab ib tug zoo txias profile, tsis ceev heev los yog qeeb heev.qeeb dhau thiab koj tau txais qee yam ntawm cov lus hais saum toj no tsis zoo cua txias teeb meem.Kev txias sai heev tuaj yeem ua rau thermal shock rau cov khoom.
Zuag qhia tag nrho, qhov tseem ceeb ntawm SMT reflow kauj ruam tsis tuaj yeem kwv yees.Cov txheej txheem yuav tsum tau tswj kom zoo kom tau txais txiaj ntsig zoo.
Post lub sij hawm: May-30-2023