Ntchito ya kuwotcherera reflow mu njira ya SMT

Reflow soldering ndiyo njira yowotcherera yomwe imagwiritsidwa ntchito kwambiri pamakampani a SMT.Njira inanso yowotcherera ndi yowotchera mafunde.Reflow soldering ndi yoyenera pazigawo za chip, pomwe ma wave soldering ndi oyenera ma pini amagetsi.

Reflow soldering ndi njira yopangira reflow soldering.Mfundo yake ndi kusindikiza kapena jekeseni mlingo woyenera wa solder phala pa PCB pad ndi kumata lolingana SMT chigamba processing zigawo zikuluzikulu, ndiye ntchito otentha mpweya convection Kutentha kwa ng'anjo reflow kusungunula solder phala, ndipo potsiriza kupanga odalirika solder olowa. kupyolera mu kuziziritsa.Lumikizani zigawozo ndi PCB pad kuti mugwire ntchito yolumikizira makina ndi kulumikizana kwamagetsi.Nthawi zambiri, reflow soldering imagawidwa m'magawo anayi: kutenthetsa, kutentha kosalekeza, kuyambiranso ndi kuziziritsa.

1. Preheating zone

Preheating zone: ndi gawo loyamba la kutentha kwa chinthucho.Cholinga chake ndi kutenthetsa mankhwala mwamsanga kutentha ndi yambitsa solder phala flux.Panthawi imodzimodziyo, ndi njira yowotchera yofunikira kuti tipewe kutaya kwa kutentha kwa zigawo zikuluzikulu zomwe zimayambitsidwa ndi kutentha kwachangu panthawi yomizidwa ndi malata.Choncho, mphamvu ya kukwera kwa kutentha kwa mankhwalawa ndi yofunika kwambiri ndipo iyenera kuyendetsedwa mosiyanasiyana.Ngati ithamanga kwambiri, imatulutsa kugwedezeka kwamafuta, PCB ndi zigawo zake zidzakhudzidwa ndi kupsinjika kwamafuta ndikuwononga.Pa nthawi yomweyo, zosungunulira mu solder phala adzakhala volatilize mofulumira chifukwa mofulumira Kutentha, chifukwa splashing ndi mapangidwe solder mikanda.Ngati ndi pang'onopang'ono, solder phala zosungunulira si volatilize mokwanira ndi kukhudza kuwotcherera khalidwe.

2. Kutentha kwanthawi zonse

Kutentha kwanthawi zonse: cholinga chake ndikukhazikitsa kutentha kwa chinthu chilichonse pa PCB ndikukwaniritsa mgwirizano momwe mungathere kuti muchepetse kusiyana kwa kutentha pakati pa chinthu chilichonse.Panthawi imeneyi, nthawi yotentha ya chigawo chilichonse ndi yaitali, chifukwa zigawo zing'onozing'ono zidzafika bwino poyamba chifukwa cha kutentha kochepa, ndipo zigawo zikuluzikulu zimafunikira nthawi yokwanira kuti zigwirizane ndi zigawo zing'onozing'ono chifukwa cha kuyamwa kwakukulu kwa kutentha, ndikuonetsetsa kuti kutentha kumatuluka. mu solder phala kwathunthu volatilized.Panthawi imeneyi, pansi pa kusinthasintha, oxide pa pad, mpira wa solder ndi chigawo cha pini zidzachotsedwa.Panthawi imodzimodziyo, kutulutsako kudzachotsanso banga lamafuta pamwamba pa chigawocho ndi pad, kuonjezera malo otsekemera ndikulepheretsa kuti chigawocho chisakhale oxidized kachiwiri.Pambuyo pa siteji iyi, zigawo zonse ziyenera kukhala zofanana kapena kutentha, mwinamwake kuwotcherera kosauka kungachitike chifukwa cha kusiyana kwakukulu kwa kutentha.

Kutentha ndi nthawi ya kutentha kosalekeza kumadalira zovuta za mapangidwe a PCB, kusiyana kwa mitundu yamagulu ndi chiwerengero cha zigawo.Nthawi zambiri amasankhidwa pakati pa 120-170 ℃.Ngati PCB ndi yovuta kwambiri, kutentha kwa nthawi zonse kutentha kuyenera kutsimikiziridwa ndi kutentha kwa rosin kufewetsa monga chofotokozera, kuti muchepetse nthawi yowotcherera ya zone yowonjezereka mu gawo lotsatira.Kutentha kwanthawi zonse kwa kampani yathu nthawi zambiri kumasankhidwa pa 160 ℃.

3. Malo a Reflux

Cholinga cha reflow zone ndikupangitsa kuti phala la solder lisungunuke ndikunyowetsa pedi pamwamba pa chinthucho kuti chiwotchedwe.

Pamene bolodi PCB akulowa m'dera reflow, kutentha adzauka mofulumira kupanga solder phala kufika boma kusungunuka.Malo osungunuka a phala la lead solder SN: 63 / Pb: 37 ndi 183 ℃, ndi phala lopanda kutsogolo SN: 96.5 / ag: 3 / Cu: 0. Malo osungunuka a 5 ndi 217 ℃.M'chigawo chino, chowotcha chimapereka kutentha kwambiri, ndipo kutentha kwa ng'anjo kudzayikidwa pamwamba kwambiri, kotero kuti kutentha kwa solder phala kudzakwera mofulumira mpaka kutentha kwakukulu.

Kutentha kwapamwamba kwa reflow soldering curve nthawi zambiri kumatsimikiziridwa ndi malo osungunuka a solder phala, bolodi la PCB ndi kutentha kosagwira kutentha kwa gawo lomwelo.Kutentha kwapamwamba kwa zinthu zomwe zili m'dera la reflow zimasiyana malinga ndi mtundu wa solder phala logwiritsidwa ntchito.Nthawi zambiri, kutentha kwapamwamba kwambiri kwa phala lopanda zitsulo kumakhala 230 ~ 250 ℃, ndipo phala la lead solder nthawi zambiri ndi 210 ~ 230 ℃.Ngati kutentha kwapamwamba kumakhala kotsika kwambiri, ndikosavuta kupanga kuwotcherera kozizira komanso kunyowetsa kosakwanira kwa zida za solder;Ngati ndi okwera kwambiri, gawo lapansi la epoxy resin mtundu wagawo ndi zigawo za pulasitiki ndizosavuta kuyika, PCB kuchita thovu ndi delamination, komanso zipangitsa kuti pakhale zitsulo zochulukirapo za eutectic zitsulo, zomwe zimapangitsa kuti olowa olumikizirana asokonekere komanso mphamvu yowotcherera ikhale yofooka, zomwe zimakhudza makina katundu wa mankhwala.

Ziyenera kutsindika kuti kusinthasintha kwa solder phala m'dera reflow kumathandiza kulimbikitsa wetting pakati pa solder phala ndi chigawo kuwotcherera mapeto ndi kuchepetsa mavuto padziko la solder phala pa nthawi ino, koma Kukwezeleza Flux adzakhala. kukhala woletsedwa chifukwa cha mpweya wotsalira ndi zitsulo pamwamba oxides mu ng'anjo reflow.

Nthawi zambiri, kutentha kwa ng'anjo yabwino kumayenera kukumana kuti kutentha kwakukulu kwa mfundo iliyonse pa PCB kukhale kofanana momwe kungathekere, ndipo kusiyana kwake kusapitirire madigiri 10.Ndi njira iyi yokha yomwe tingatsimikizire kuti ntchito zonse zowotcherera zatha bwino pamene mankhwala alowa m'malo ozizira.

4. Malo ozizira

Cholinga cha zone yozizira ndikuziziritsa mwachangu tinthu tating'onoting'ono ta solder tomwe timasungunuka ndipo mwachangu kupanga zolumikizana zowoneka bwino zokhala ndi radian pang'onopang'ono komanso malata.Choncho, mafakitale ambiri adzalamulira malo ozizira bwino, chifukwa ndi abwino kupanga mgwirizano wa solder.Nthawi zambiri, kuzizira kofulumira kumapangitsa kuti phala losungunuka lizizizira komanso kuti likhale lotchinga, zomwe zimapangitsa kuti pakhale kutsetsereka, kunona komanso kung'ambika kwa olowa.Kutsika kozizira kwambiri kumapangitsa kuti zinthu zoyambira za PCB pad ziphatikizidwe ndi phala la solder, zomwe zimapangitsa kuti olowa nawo asokonekere, kuwotcherera opanda kanthu komanso olowa akuda.Komanso, magazini onse zitsulo pa chigawo solder mapeto adzasungunuka pa malo olowa solder, chifukwa chonyowa kukana kapena osauka kuwotcherera pa chigawo solder mapeto, Zimakhudza kuwotcherera khalidwe, kotero kuzirala wabwino mlingo n'kofunika kwambiri kwa solder olowa kupanga. .Nthawi zambiri, wogulitsa phala solder amalangiza solder olowa kuzirala mlingo ≥ 3 ℃ / s.

Makampani a Chengyuan ndi kampani yomwe imagwira ntchito popereka zida za SMT ndi PCBA.Imakupatsirani njira yabwino kwambiri.Ili ndi zaka zambiri zopanga komanso luso la R & D.Akatswiri aukadaulo amapereka malangizo oyikapo ndikugulitsa pambuyo pa khomo ndi khomo, kuti musakhale ndi nkhawa kunyumba.