Bayanin Maimaitawa mara gubar: Nau'in jiƙa vs. Nau'in Slumping

Reflow soldering wani tsari ne wanda manna solder ke yin zafi kuma yana canzawa zuwa wani narkakkar yanayi domin haɗa fil ɗin da PCB pads tare har abada.

Akwai matakai/shiyoyi huɗu zuwa wannan tsari - preheating, jiƙa, sake kwarara da sanyaya.

Don nau'in bayanan martaba na gargajiya na trapezoidal akan manna mai siyar da gubar kyauta wanda Bittele ke amfani da shi don tsarin taro na SMT:

1. Yankin Preheating: Preheat yawanci yana nufin ƙara yawan zafin jiki daga al'ada zafin jiki zuwa 150 ° C kuma daga 150 ° C zuwa 180 C. Yanayin zafin jiki daga al'ada zuwa 150 ° C bai wuce 5 ° C / sec (a 1.5 ° C ~ 3 ° C / s), kuma lokacin tsakanin 150 ° C zuwa 180 ° C yana kusa da 60 ~ 220 sec.Amfanin jinkirin dumi shine barin sauran ƙarfi da ruwa a cikin tururin manna su fito akan lokaci.Hakanan yana barin manyan abubuwan haɗin gwiwa suyi zafi akai-akai tare da sauran ƙananan abubuwan.
2. Yankin jinƙai: Lokacin preheating daga 150 ° C zuwa madaidaicin alloy kuma ana san shi azaman lokacin jiƙa, wanda ke nufin jujjuyawa yana aiki kuma yana cire maye gurbin oxidized akan saman ƙarfe don haka yana shirye don yin haɗin gwiwa mai kyau na solder. tsakanin abubuwan da aka gyara da pads na PCB.
3. Yanki mai sake gudana: Yankin maimaitawa, wanda kuma ake kira "lokacin da ke sama da ruwa" (TAL), shine ɓangaren aiwatar da mafi girman zafin jiki.Mafi yawan zafin jiki na yau da kullun shine 20-40 ° C sama da ruwa.
4. Yanki mai sanyaya: A cikin yankin sanyaya, zafin jiki yana raguwa a hankali kuma yana yin ƙwaƙƙwaran haɗin gwiwa.Ana buƙatar yin la'akari da matsakaicin matsakaicin da za'a iya kwantar da hankali don guje wa kowane lahani daga faruwa.Ana ba da shawarar ƙimar sanyi na 4°C/s.

Akwai bayanan martaba daban-daban guda biyu da ke cikin tsarin sake kwarara - nau'in soaking da nau'in slumping.

Nau'in Soaking yana kama da siffar trapezoidal yayin da nau'in slumping yana da siffar delta.Idan allon yana da sauƙi kuma babu hadaddun abubuwa irin su BGAs ko manyan abubuwan haɗin gwiwa akan allon, bayanin martabar nau'in slumping zai zama mafi kyawun zaɓi.