PCB is an indispensable part of modern electronics and the carrier of electrical connection of electronic components. Tare da ci gaba da ci gaban fasahar lantarki, yawancin PCB yana samun girma da girma, don haka akwai ƙarin buƙatu don tsarin walda. Saboda haka, wajibi ne a yi nazari da kuma yin hukunci a kan abubuwan da suka shafi ingancin walda na PCB da kuma gano abubuwan da ke haifar da lahani na walda, don inganta haɓakawa da inganta ingancin PCB gabaɗaya. Let’s take a look at the causes of welding defects on Kwamitin PCB.

Why do PCB boards have welding defects

1. A weldability na kewaye hukumar rami rinjayar waldi quality

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Ramin weldability na allon kewayawa ba shi da kyau, zai haifar da lahani na walda mai kama-da-wane, yana shafar ma’auni na abubuwan da ke cikin kewaye, haifar da rashin kwanciyar hankali na abubuwan da ke tattare da kwamitin multilayer da jigilar layin ciki, haifar da gazawar duk aikin kewaye.

Babban abubuwan da ke shafar solderability na allon da’ira bugu sune:

(1) abun da ke ciki na solder da yanayin mai siyarwar. Solder wani muhimmin sashi ne na tsarin sarrafa sinadarai na walda, ya ƙunshi kayan sinadarai masu ɗauke da ruwa, wanda aka saba amfani da shi ƙarancin narkewar ƙarfe eutectic karfe shine Sn-Pb ko Sn-Pb-Ag. Ya kamata a sarrafa abin da ke cikin ƙazanta don hana oxide ɗin da ƙazanta ke samarwa daga narkar da su ta hanyar juyi. Ayyukan juyi shine don taimakawa mai siyarwar jika saman da’irar farantin da aka siyar ta hanyar canja wurin zafi da cire tsatsa. Farar rosin da barasa isopropyl ana amfani da su gabaɗaya.

(2) Welding zafin jiki da karfe farantin surface tsabta kuma zai shafi weldability. A zafin jiki ne ma high, da solder watsa gudun ne kara, a wannan lokaci yana da wani sosai high aiki, zai sa da kewaye hukumar da solder narke surface da sauri hadawan abu da iskar shaka, walda lahani, kewaye hukumar surface gurbatawa kuma zai shafi weldability don samar da lahani. ciki har da kwano beads, kwalayen kwano, buɗe kewaye, sheki ba shi da kyau.

2. Lalacewar walda ta hanyar warping

Allolin kewayawa da abubuwan da aka gyara sun lalace yayin walda, yana haifar da lahani kamar walda mai kama da gajeriyar kewayawa saboda nakasar damuwa. Yawanci yana faruwa ne sakamakon rashin daidaituwar yanayin zafi tsakanin sama da ƙananan sassa na allon kewayawa. Don babban PCBS, warping shima yana faruwa lokacin da hukumar ta faɗi ƙarƙashin nauyinta. Na’urorin PBGA na yau da kullun suna kusan 0.5mm nesa da allon da’ira da aka buga. Idan abubuwan da ke kan allon kewayawa suna da girma, haɗin gwiwa na solder zai kasance cikin damuwa na dogon lokaci yayin da allon kewayawa ya dawo daidai da yanayinsa bayan sanyaya. Idan an ɗaga bangaren da 0.1mm, zai isa ya haifar da da’irar buɗewar walda mai kama-da-wane.

3, zane na allon kewayawa yana rinjayar ingancin walda

A cikin shimfidar wuri, girman allon kewayawa yana da girma, kodayake waldawa yana da sauƙin sarrafawa, amma layin bugu yana da tsayi, haɓaka yana ƙaruwa, ƙarfin hana surutu yana raguwa, farashin yana ƙaruwa; Ya yi ƙanƙanta, raguwar zafi yana raguwa, walda ba ta da sauƙin sarrafawa, sauƙin bayyana layin da ke kusa da juna suna tsoma baki tare da juna, kamar kutsawar wutar lantarki na allon kewayawa. Don haka, dole ne a inganta ƙirar allon PCB:

(1) Rage haɗin kai tsakanin manyan abubuwan haɗin gwiwa kuma rage tsangwama na EMI.

(2) Abubuwan da ke da babban nauyi (kamar fiye da 20g) yakamata a gyara su tare da goyan baya sannan kuma a yi musu walda.

(3) Ya kamata a yi la’akari da zubar da zafi na abubuwan dumama don hana manyan lahani na δ T da sake yin aiki, kuma ya kamata a kiyaye abubuwa masu zafi daga tushen dumama.

(4) Shirye-shiryen abubuwan da aka gyara a matsayin layi daya kamar yadda zai yiwu, don haka ba kawai kyau da sauƙi ga walda ba, dace da samar da taro. 4∶3 ƙirar allon kewayawa na rectangular shine mafi kyau. Kar a canza nisan waya don guje wa yankewa a cikin wayoyi. Lokacin da allon kewayawa ya yi zafi na dogon lokaci, murfin jan karfe yana da sauƙi don faɗaɗawa kuma ya faɗi. Saboda haka, ya kamata a kauce wa babban jakar tagulla.

A taƙaice, don tabbatar da ingancin hukumar PCB gabaɗaya, ya zama dole a yi amfani da ingantaccen solder, inganta solderability na hukumar PCB, da hana warping don hana lahani a cikin tsarin samarwa.