Cikakkun bayanai da ya kamata a kula da su lokacin sayar da PCB

Bayan an sarrafa laminate ɗin tagulla don samarwa Kwamitin PCB, daban-daban ta hanyar ramuka, da ramukan taro, an haɗa abubuwa daban-daban. Bayan haɗawa, don sanya abubuwan da aka haɗa su kai ga haɗin kai tare da kowane da’irar PCB, dole ne a aiwatar da aikin walda na Xuan. An kasu brazing zuwa hanyoyi guda uku: sayar da igiyar ruwa, reflow soldering da manual soldering. Abubuwan da aka saka soket gabaɗaya ana haɗa su ta hanyar sayar da igiyoyin ruwa; haɗin brazing na abubuwan da aka ɗora a saman gabaɗaya yana amfani da reflow soldering; mutum aka gyara da aka gyara ne akayi daban-daban manual (lantarki chrome) saboda shigarwa tsari bukatun da mutum gyara waldi. Iron) walda.

ipcb

1. Solder juriya na jan karfe clad laminate

Copper clad laminate shine kayan da ake amfani da su na PCB. A lokacin brazing, yana ci karo da hulɗar abubuwa masu zafi a nan take. Sabili da haka, tsarin walda na Xuan wani muhimmin nau’i ne na “matsayi mai zafi” ga lamintin tagulla da kuma gwajin juriya na zafi na laminate na jan karfe. Laminates ɗin da aka yi da jan ƙarfe suna tabbatar da ingancin samfuran su yayin girgizar zafi, wanda shine muhimmin al’amari na tantance juriya na zafi na laminates na jan karfe. A sa’i daya kuma, amincin lamintin tagulla yayin waldar Xuan shima yana da nasaba da karfin ja da kansa, da karfin bawo a karkashin yanayin zafi, da danshi da juriya na zafi. Don tsarin aikin brazing na laminates na jan karfe, ban da abubuwan juriya na al’ada, a cikin ‘yan shekarun nan, don inganta amincin laminates na jan karfe a cikin waldi na Xuan, an ƙara wasu ma’aunin aikin aikace-aikacen da abubuwan kima. Irin su shayar da danshi da gwajin juriya na zafi (jiyya na 3 h, sannan gwajin 260 ℃ dip soldering test), gwajin shayarwar reflow na siyarwa (wanda aka sanya shi a 30 ℃, yanayin zafi 70% na ƙayyadadden lokaci, don gwajin siyarwar reflow) da sauransu. . Kafin samfuran laminate ɗin tagulla su bar masana’anta, masana’antar laminate ɗin tagulla za ta yi gwajin juriya mai tsauri (wanda aka fi sani da blistering thermal shock) gwargwadon ma’auni. Masu kera da’ira da aka buga suma yakamata su gano wannan abu cikin lokaci bayan lamintin tagulla ya shiga masana’anta. A lokaci guda, bayan an samar da samfurin PCB, yakamata a gwada aikin ta hanyar simintin yanayin siyar da igiyar ruwa a cikin ƙananan batches. Bayan tabbatar da cewa irin wannan nau’in substrate ya cika buƙatun mai amfani dangane da juriya ga siyarwar nutsewa, PCB na wannan nau’in ana iya samar da shi da yawa kuma a aika shi zuwa masana’antar cikakken injin.

Hanyar auna juriya na laminates na jan ƙarfe shine ainihin iri ɗaya da na duniya (GBIT 4722-92), ma’aunin IPC na Amurka (IPC-410 1), da ma’aunin JIS na Japan (JIS-C-6481-1996) . Babban buƙatun su ne:

①Hanyar yanke hukunci shine “hanyar shawagi mai iyo” (samfurin yana iyo akan farfajiyar siyarwa);

② Girman samfurin shine 25 mm X 25 mm;

③Idan ma’aunin ma’aunin zafin jiki shine ma’aunin zafi da sanyio na mercury, yana nufin cewa daidaitaccen matsayi na shugaban mercury da wutsiya a cikin solder shine (25 ± 1) mm; Matsayin IPC shine 25.4 mm;

④ Zurfin solder wanka bai kasa da 40 mm ba.

Ya kamata a lura da cewa: Matsayin ma’aunin zafin jiki yana da tasiri mai mahimmanci akan daidai kuma daidaitaccen tunani na matakin juriya na dip solder na jirgi. Gabaɗaya, tushen dumama tin ɗin yana a ƙasan wankan kwano. Mafi girma (zurfin) nisa tsakanin ma’aunin ma’aunin zafin jiki da saman mai siyar, mafi girma da sabawa tsakanin zazzabi na solder da zafin da aka auna. A wannan lokacin, ƙananan zafin jiki na ruwa ya fi zafin da aka auna, tsawon lokacin farantin tare da juriya na tsomawa wanda aka auna ta hanyar samfurin taso kan ruwa zuwa kumfa.

2. sarrafa igiyar ruwa

A cikin tsarin sayar da igiyar ruwa, yawan zafin jiki na siyarwar shine ainihin yanayin zafin mai siyar, kuma wannan zafin yana da alaƙa da nau’in siyarwar. Yawan zafin jiki na walda ya kamata a sarrafa ƙasa da 250’c. Matsakaicin zafin jiki na walda yana shafar ingancin walda. Yayin da yawan zafin jiki ya karu, lokacin siyarwar dip yana raguwa sosai. Idan yawan zafin jiki na siyarwar ya yi yawa, zai haifar da da’irar (bututun jan ƙarfe) ko ma’adinan zuwa blistering, delamination, da mummunan warpage na allo. Don haka, zafin walda dole ne a sarrafa shi sosai.

Uku, reflow sarrafa walda

Gabaɗaya, yawan zafin jiki na sake kwarara ya ɗan yi ƙasa kaɗan fiye da zazzabi soldering. Saitin zazzabi mai sake kwarara yana da alaƙa da abubuwa masu zuwa:

①Nau’in kayan aiki don reflow soldering;

② Yanayin saitin saurin layi, da sauransu;

③Nau’in da kauri daga cikin kayan aiki;

④ Girman PCB, da dai sauransu.

Saitin zafin jiki na reflow soldering ya bambanta da zafin jiki na PCB. A daidai wannan saitin zafin jiki don reflow soldering, da surface zafin jiki na PCB ne daban-daban saboda irin da kauri daga cikin substrate abu.

A lokacin reflow soldering tsari, zafi juriya iyaka na substrate zafin jiki inda jan karfe kumbura (kumfa) zai canza tare da preheating zafin jiki na PCB da gaban ko rashi danshi sha. Ana iya gani daga Hoto na 3 cewa lokacin da zafin zafin jiki na PCB (zazzabi na saman ƙasa) ya yi ƙasa, iyakar juriya na zafi na yanayin zafin ƙasa inda matsalar kumburi ta faru shima ƙasa. Ƙarƙashin yanayin zafin da aka saita ta hanyar sayar da reflow da preheating zafin jiki na reflow soldering sun kasance akai-akai, zafin jiki na saman yana faduwa saboda shayar da danshi na substrate.

Hudu, walda da hannu

A gyara waldi ko raba manual waldi na musamman aka gyara, da surface zafin jiki na lantarki ferrochrome ake bukata ya zama kasa 260 ℃ ga takarda na tushen jan karfe laminates, kuma a kasa 300 ℃ ga gilashin fiber zane-tushen jan karfe laminates. Kuma gwargwadon yadda zai yiwu don rage lokacin waldi, buƙatun gabaɗaya; takarda substrate 3s ko žasa, gilashin fiber zane substrate ne 5s ko žasa.