Kusankhidwa kwa PCB Ukadaulo wokutira pamwamba pa SMT soldering mu SMT processing makamaka zimadalira mtundu wa zigawo zomaliza zomwe zasonkhanitsidwa, ndipo njira yochizira pamwamba idzakhudza kupanga, kusonkhanitsa ndi kugwiritsa ntchito komaliza kwa PCB. Zotsatirazi zikuwonetsa mwachidule maziko osankhidwa a PCB solderability pamwamba ❖ kuyanika.

Posankha ❖ kuyanika pamwamba solderable wa PCB mu chigamba processing, osankhidwa solder aloyi zikuchokera ndi ntchito mankhwala ayenera kuganiziridwa.

1. Solder aloyi zikuchokera

Kugwirizana kwa zokutira za PCB pad ndi alloy solder ndiye chinthu chofunikira kwambiri posankha zokutira za PCB zomwe zimatha kugulitsidwa (kubisa). Izi zimakhudza mwachindunji kugulitsa ndi kudalirika kwa mgwirizano wazitsulo zogulitsa mbali zonse za pedi. Mwachitsanzo, mpweya wotentha wa Sn-Pb uyenera kusankhidwa wa aloyi a Sn-pb, ndipo mpweya wotentha wachitsulo wopanda lead kapena aloyi wopanda lead uyenera kusankhidwa kuti ukhale wopanda lead.

2. Zofunikira zodalirika

Zogulitsa zomwe zili ndi zofunikira zodalirika ziyenera kusankha kaye mpweya wotentha womwewo ngati aloyi ya solder, yomwe ili yabwino kwambiri kuti igwirizane. Kuphatikiza apo, Ni-Au (ENIG) yapamwamba imatha kuganiziridwanso, chifukwa mphamvu yolumikizira mawonekedwe a alloy Ni3Sn4 pakati pa Sn ndi Ni ndiyokhazikika kwambiri. Ngati ENIG ikugwiritsidwa ntchito, gawo la Ni liyenera kulamulidwa kuti likhale> 3 µm (5 mpaka 7 µm), ndi wosanjikiza wa Au uyenera kukhala ≤ 1 µm (0.05 mpaka 0.15 µm), ndipo zofunikira za solderability ziyenera kuperekedwa kwa wopanga.

3. Njira yopanga

Posankha PCB solderable pamwamba ❖ kuyanika (plating) wosanjikiza, ngakhale PCB PAD ❖ kuyanika wosanjikiza ndi kupanga ndondomeko ayeneranso kuganizira. Hot air leveling (HASL) ili ndi kuwotcherera kwabwino, imatha kugwiritsidwa ntchito powotcherera mbali ziwiri, ndipo imatha kupirira kuwotcherera angapo. Komabe, popeza pamwamba pa pad silathyathyathya mokwanira, sikoyenera phula lopapatiza. OSP ndi malata omiza (I-Sn) ndi oyenera kwambiri kusonkhana kwa mbali imodzi ndi njira imodzi yogulitsira.