Kodi mphamvu ya chinyezi pa PCBA ndi yofunika bwanji?

PCB chifukwa cha kulondola komanso kukhwima kwake, zofunikira za thanzi la chilengedwe pa msonkhano uliwonse wa PCB ndizokwera kwambiri, ndipo zokambirana zina zimakhala ndi "kuwala kwachikasu" tsiku lonse. Chinyezi, ndi chimodzi mwa zizindikiro zomwe ziyenera kuyendetsedwa mosamalitsa, lero tikambirana za momwe chinyezi chimakhudzira PCBA.

"Chinyezi" chofunikira

Chinyezi ndichizindikiro chovuta kwambiri komanso choyendetsedwa bwino pakupanga. Chinyezi chochepa chingayambitse kuuma, kuwonjezeka kwa ESD, kuchuluka kwa fumbi, kutsekeka kwa ma templates mosavuta, komanso kuvala kwa ma template. Kuchita kwatsimikizira kuti chinyezi chochepa chidzakhudza mwachindunji ndikuchepetsa mphamvu yopangira. Kukwera kwambiri kumapangitsa kuti zinthuzo zizitha kuyamwa chinyezi, zomwe zimapangitsa kuti pakhale delamination, popcorn zotsatira, ndi mipira ya solder. Chinyezi chimachepetsanso mtengo wa TG wazinthu ndikuwonjezera kusinthasintha kwamphamvu panthawi yowotcherera.

Chiyambi cha chinyezi

Pafupifupi malo onse olimba (monga zitsulo, galasi, ceramics, silicon, etc.) amakhala ndi madzi otsekemera (osanjikiza amodzi kapena angapo) omwe amawonekera pamene kutentha kwa pamwamba kumafanana ndi kutentha kwa mame a mpweya wozungulira. kutengera kutentha, chinyezi, komanso kuthamanga kwa mpweya). Kukangana pakati pa zitsulo ndi zitsulo kumawonjezeka ndi kuchepa kwa chinyezi, ndipo pa chinyezi cha 20% RH ndi pansi, kukangana ndi 1.5 nthawi zambiri kuposa chinyezi cha 80% RH.

Porous kapena chinyezi kuyamwa pamalo (epoxy resins, mapulasitiki, fluxes, etc.) amakonda kuyamwa zigawo izi kuyamwa, ndipo ngakhale pamene kutentha pamwamba ndi pansi pa mame (condensation), kuyamwa wosanjikiza munali madzi sikuwoneka pamwamba pa zinthu.

Ndi madzi omwe ali m'magawo ang'onoang'ono okhala ndi molekyulu imodzi pamalo awa omwe amalowa mu chipangizo cha pulasitiki cha encapsulation (MSD), ndipo zigawo zoyamwa za molekyulu imodzi zikafika zigawo 20 mu makulidwe, chinyezi chomwe chimatengedwa ndi zigawo zoyamwa za molekyulu imodzi pamapeto pake. zimayambitsa popcorn effect panthawi ya reflow soldering.

Mphamvu ya chinyezi pakupanga

Chinyezi chimakhala ndi zotsatira zambiri pakupanga ndi kupanga. Nthawi zambiri, chinyezi sichiwoneka (kupatula kulemera kwake), koma zotsatira zake ndi pores, voids, solder spatter, solder mipira, ndi voids pansi.

Muzochita zilizonse, kuwongolera chinyezi ndi chinyezi ndikofunikira kwambiri, ngati mawonekedwe a thupi ndi osazolowereka, chomaliza sichili choyenera. Chifukwa chake, msonkhano wanthawi zonse uyenera kuwonetsetsa kuti chinyezi ndi chinyezi cha gawo lapansi zimayendetsedwa bwino kuti zitsimikizire kuti zizindikiro za chilengedwe pakupanga zinthu zomalizidwa zili mkati mwazomwe zafotokozedwa.