I-PCB ngenxa yokuchaneka kwayo nokuba ngqongqo kwayo, iimfuno zempilo yokusingqongileyo kuzo zonke iindibano zocweyo zePCB ziphezulu kakhulu, kwaye ezinye iindibano zocweyo zide zibe sesichengeni “sokukhanya okutyheli” imini yonke. Ukufuma, kwakhona sesinye sezibonakaliso ezifuna ukulawulwa ngokungqongqo, namhlanje siza kuthetha ngempembelelo yokufuma kwi-PCBA.
"Ukufuma" okubalulekileyo
Ukufuma sisalathisi esibaluleke kakhulu kwaye silawulwa ngokungqongqo kwinkqubo yokuvelisa. Ukufuma okuphantsi kunokubangela ukoma, ukwanda kwe-ESD, ukwanda kwamanqanaba othuli, ukuvaleka ngokulula kokuvuleka kwetemplate, kunye nokunyuka kokunxiba kwetemplate. Uqheliselo lubonakalise ukuba ukufuma okuphantsi kuya kuchaphazela ngokuthe ngqo kwaye kunciphise umthamo wemveliso. Ukuphakama kakhulu kuya kubangela ukuba izinto zifunxe ukufuma, okukhokelela kwi-delamination, iziphumo ze-popcorn, kunye neebhola ze-solder. Ukufuma kwakhona kunciphisa ixabiso le-TG lezinto eziphathekayo kwaye kwandisa i-warping eguquguqukayo ngexesha le-welding ye-reflow.
Intshayelelo yokufuma komhlaba
Phantse yonke imiphezulu eqinileyo (enjengentsimbi, iglasi, iiseramikhi, isilicon, njl. njl.) inomaleko omanzi afunxa amanzi (omnye okanye oneemolekyuli ezininzi) obonakala xa ubushushu bomphezulu bulingana neqondo lombethe lomoya ojikelezileyo. kuxhomekeke kwiqondo lobushushu, ukufuma, kunye noxinzelelo lomoya). Ukruthakruthwano phakathi kwesinyithi kunye nentsimbi luyenyuka ngokuncipha kokufuma, kwaye xa kufumama okunxulumene ne-20% RH nangaphantsi, ukukhuhlana kukuphinda-phindwe ka-1.5 ngaphezulu kokufuma okunxulumene nama-80% e-RH.
Imiphezulu efunxayo okanye ukufuma (i-epoxy resins, iplastiki, i-fluxes, njl.njl.) ikholisa ukufunxa le maleko efunxayo, kwaye naxa ubushushu bomphezulu bungaphantsi kwendawo yombethe (i-condensation), umaleko ofunxayo oqulathe amanzi awubonakali kumphezulu womhlaba. izinto eziphathekayo.
Ngamanzi akwi maleko efunxa imolekyuli enye kule miphezulu ethi igqobhoze kwisixhobo sokufunxa seplastiki (MSD), kwaye xa umaleko ofunxayo onemolekyuli enye usondela kumaleko angama-20 ngobunzima, ukufuma okufunxwa yile maleko yokufunxa imolekyuli enye ekugqibeleni. ibangela isiphumo se-popcorn ngexesha le-reflow soldering.
Impembelelo yokufuma ngexesha lokuvelisa
Ukufuma kuneempembelelo ezininzi kwimveliso nakwimveliso. Ngokuqhelekileyo, umswakama awubonakali (ngaphandle kobunzima obuninzi), kodwa iziphumo ziyi-pores, i-voids, i-solder spatter, iibhola ze-solder, kunye ne-bottom-fill voids.
Kuyo nayiphi na inkqubo, ukulawulwa komswakama kunye nomswakama kubaluleke kakhulu, ukuba ukubonakala kwendawo yomzimba akuqhelekanga, imveliso egqityiweyo ayifanelekanga. Ngoko ke, iworkshop eqhelekileyo kufuneka iqinisekise ukuba umswakama kunye nomswakama we-substrate surface kulawulwa ngokufanelekileyo ukuqinisekisa ukuba izikhombisi zokusingqongileyo kwinkqubo yokuvelisa imveliso egqityiweyo ziphakathi koluhlu oluchaziweyo.
Ixesha lokuposa: Mar-26-2024
