Lub hom phiaj tseem ceeb ntawm PCB ci yog kom dehumidify muaj nyob rau hauv pcb lossis nqus tau ntawm lub ntiaj teb sab nraud, vim qee cov ntaub ntawv siv hauv PCB nws tus kheej yooj yim tsim cov dej lwg me me.
Tsis tas li ntawd, tom qab tus PCB yog tsim thiab muab tso rau ib lub sijhawm, muaj ib lub sijhawm los nqus noo noo hauv ib puag ncig ntawm PCB paj yeeb lossis delamination.
Vim tias thaum tus PCB tau muab tso rau hauv ib puag ncig uas qhov kub tshaj 100 ° C, cov dej soldering, dej yuav hloov mus rau hauv lub vapor thiab tom qab ntawd nthuav dav nws ntim.
Lub nrawm dua rau cov cua sov yog thov rau PCB, cov dej ntws nrawm dua; Qhov siab dua qhov ntsuas kub, qhov ntau dua qhov ntim ntawm cov dej vapor; Thaum cov dej dej ntws tsis tuaj yeem khiav tawm ntawm PCB tam sim, muaj txoj hmoo zoo ntawm kev nthuav dav PCB.
Tshwj xeeb, cov z kev taw qhia ntawm PCB yog qhov tsis yooj yim tshaj plaws. Qee zaum cov vias ntawm txheej ntawm PCB tej zaum yuav tawg, thiab qee zaum nws yuav ua rau kev sib cais ntawm cov khaubncaws sab nraud ntawm PCB. Txawm tias muaj qhov hnyav dua, txawm tias cov pcb tuaj yeem pom. Tshwm sim xws li blistering, o, thiab bursting;
Qee zaum txawm hais tias cov xwm txheej saum toj no tsis pom nyob sab nraum tus PCB, nws yog qhov sab hauv. Sij hawm dhau los, nws yuav ua rau muaj kev tsis ruaj khov ntawm cov khoom hluav taws xob, lossis chaw noj mov thiab lwm yam teeb meem, thiab nws thiaj ua rau khoom tsis ua haujlwm.
Kev tsom xam ntawm qhov tseeb qhov tseeb ntawm PCB tawg thiab tiv thaiv kev ntsuas
Tus txheej txheem PCB yog qhov teeb meem heev. Thaum ci, lub ntim thawj yuav tsum tau muab tshem tawm ua ntej nws tuaj yeem muab tso rau hauv qhov cub, thiab tom qab ntawd qhov kub yuav tsum tau ua rau muaj kev kub ntxhov, tab sis qhov kub yuav tsum tsis txhob siab dhau lub sijhawm ci. Ntau dhau kev nthuav dav ntawm dej vapor yuav tawg pcb.
Feem ntau, tus PCB ci kub hauv kev lag luam feem ntau tau teeb tsa thaum muaj PCB ua ntej nws tuaj yeem tsim tawm ntawm SMT kab mus rau lub refle rauv taws.
Lub sijhawm ci ntsa iab nrog cov tuab tuab thiab loj ntawm PCB. Rau cov thinner lossis loj pcbs, koj yuav tsum nias lub rooj tsavxwm nrog ib qho khoom hnyav tom qab ci. Qhov no yog txhawm rau txo lossis zam rau lub pcb qhov kev tu ncua ntawm pcb bending deformation vim kev ntxhov siab tso tawm thaum cua txias tom qab ci.
Vim tias muaj ib zaug PCB yog deformed thiab khoov, yuav muaj kev tawm tsam lossis tsis sib xws thaum luam tawm cov kev sib tw luv luv lossis cov khoob khoob khoob thaum lub sij hawm xav tsis thoob thaum lub sij hawm rearow.
PCB ci chaw
Tam sim no, kev lag luam feem ntau teeb tsa cov xwm txheej thiab sijhawm rau PCB ci raws li nram no:
1. Tus PCB tau muab ntim zoo nyob hauv 2 hlis ntawm hnub tsim khoom. Tom qab tsis tas, nws tau muab tso rau hauv qhov chaw kub thiab cov av noo tswj ib puag ncig (≦ 30 ℃ / 60% rh, raws li IPC-1601) rau ntau tshaj 5 hnub ua ntej mus online. Ci ntawm 120 ± 5 ℃ rau 1 teev.
2. Tus PCB khaws cia rau 2-6 lub hlis dhau hnub tsim khoom, thiab nws yuav tsum yog ci ntawm 120 ± 5 teev ua ntej mus online.
3. Tus PCB khaws cia rau 6-12 lub hlis dhau hnub tsim khoom, thiab nws yuav tsum yog ci ntawm 120 ± 5 ° C rau 4 teev ua ntej mus online.
4. PCB tau khaws cia ntau dua 12 lub hlis ntawm kev tsim khoom lag luam, vim tias kev ua haujlwm zoo xws li muaj kev pheej hmoo xws li phaj tawg thiab noj mov tsis zoo. Yog tias koj yuav tsum siv nws, nws pom zoo kom ci nws ntawm 120 ± 5 ° C rau 6 teev. Ua ntej pawg ntau lawm, thawj zaug sim luam tawm ob peb daim ntawm cov cam tov thiab paub tseeb tias tsis muaj teeb meem sib luag ua ntej ntau lawm.
Lwm qhov laj thawj yog tias nws tsis pom zoo kom siv cov PCBs uas tau khaws cia ntev dhau vim tias lawv txoj kev kho deg yuav maj mam poob sijhawm. Rau cov enig, lub neej txee ntawm kev lag luam yog 12 lub hlis. Tom qab lub sijhawm no txwv, nws nyob ntawm cov nyiaj kub. Lub thickness nyob ntawm lub thickness. Yog tias cov tuab tuab yog thinner, txheej npib tsib xee tuaj yeem tshwm sim ntawm cov txheej kub vim diffusion thiab tsim oxidation, uas cuam tshuam rau kev ntseeg tau.
5. Txhua lub pcbs uas tau ci yuav tsum tau muab siv tsis pub dhau 5 hnub, thiab tsis tau muaj PCBs tsis tau muab ci dua li ntawm 120 ° C rau lwm 1 teev ua ntej mus online.