Matsalolin Tsarin SMT da Mafita: Cikakken Jagora don Taro Mai Inganci na PCB

Dalilin da yasa Kula da Lalacewar Tsarin SMT yake da Muhimmanci
Fasahar Dutsen Sama (SMT) tana buƙatar daidaiton matakin micron a cikin manna, sanya sassan, da kuma sarrafa zafi. Bambancin ƙira a cikin stencil, ƙarar manna solder, ko bayanan sake kwarara na iya haifar da lahani waɗanda ke lalata amincin samfura - musamman a cikin ƙira mai yawa, mai sauri, ko mai yawa. Don aikace-aikacen sararin samaniya, motoci, likita, da sadarwa, lahani na SMT da ba a gano ba na iya haifar da mummunan gazawar filin. Wannan jagorar ta yi bayani dalla-dalla game da lahani na SMT da suka yawaita, tushen abubuwan da suka haifar, da mafita na injiniya.

1. Jifan Kabari (Tasirin Manhattan)

Ma'anar: Wani ɓangaren guntu (misali, 0201/0402) yana ɗagawa tsaye yayin sake kwarara, yana rabuwa da kushin ɗaya.

Dalilan Fasaha:

• ·Rashin daidaiton adadin manna solder tsakanin kushin da aka haɗa
• ·Matsakaicin zafi mara daidaito (misali, faɗin alamar da ba ta daidaita ba ko kuma ruwan jan ƙarfe)
• ·Yawan sake kwararar ruwa mai yawa (>2°C/sec)
• ·Tsarin buɗewar stencil mara inganci
• ·Tsarin lissafi na kushin da ya karya ƙa'idodin daidaito na IPC-7351

Mafita a Injiniya:

• ·Tsarin faifan/alamomi masu daidaito a kowace IPC-7351B jagororin
• ·Daidaita girman/girman buɗewar stencil don ƙarewar sassan
• ·Iyakance ƙimar sake kwararar ruwa zuwa 1–2°C/sec
• ·A shafa overprint na budewa (don ≤01005 marasa amfani)
• ·A guji sanya sassan kusa da manyan jiragen jan ƙarfe

2. Haɗin Solder

Ma'anar: Haɗin solder da ba a yi niyya ba tsakanin masu jagoranci/kushin da ke kusa.

Dalilan Fasaha:

• ·Manyan ramukan stencil ko girman manna mai yawa
• ·Rashin isasshen madatsar abin rufe fuska ta solder (
• ·Rashin kyawun sakin manna (misali, rashin isasshen rabon stencil)
• ·Daidaito mara kyau yayin buga stencil

Mafita a Injiniya:

• ·Aiwatar da rage budewa (misali, "kare-kashi" ga QFPs, "home-plate" ga BGAs)
• ·Inganta rabon ɓangaren buɗewa (≥1.5) da rabon yanki (≥0.66)
• ·Faɗin mashin ɗin solder ≥0.025mm don ƙirar ƙira mai kyau
• ·Tura Binciken Manna na 3D (SPI)
• ·Aiwatar da ka'idojin tsaftacewar stencil

3. Rashin isasshen mai danshi (Ba ya jika/buɗewar haɗin gwiwa)

Ma'anar: Haɗin ƙarfe mara cika saboda rashin isasshen solder.

Dalilan Fasaha:

• ·Rashin isasshen adadin manna
• ·Bayanin sake kwarara mara kyau (ƙarancin zafin kololuwa ko TAL)
• ·Kushin/shafawa na sashi
• ·Busar da manna a lokacin da ake tsawaita amfani da shi

Mafita a Injiniya:

• ·Inganta sake kwarara: Kololuwar 240–245°C, TAL 60–90s
• ·Amfani Nau'in manna 4/5
• ·A ƙayyade gamawa guda ɗaya/guda ɗaya
• ·Yanayin sarrafawa na bugu: 25±3°C, 40–60% RH

4. Canjin/Rashin Daidaito na Sassan

Ma'anar: Matsar da sassan yayin sake kwarara.

Dalilan Fasaha:

• ·Rashin isasshen manna
• ·Matsalolin girgizar na'ura/matsalolin convector
• ·Ƙarfin bututun ƙarfe mara daidai/tsawo z
• ·PCB warpage kusa da Tg

Mafita a Injiniya:

• ·Ƙarfin manna manna > 500g/mm²
• ·Daidaita wurin da aka zaɓa: ≤30μm daidai, ƙarfin 0.2–0.5N
• ·Sarrafa saurin fanka da girgizar na'ura mai jigilar kaya
• ·Amfani FR-4 Tg170+ ko tallafin kayan aiki

5. Ƙunshin Haɗin gwiwa na Solder

Ma'anar: Rufewar iskar gas yana haifar da ramuka a cikin gidajen abinci.

Yankunan da ke da Haɗari sosai: Kushin zafi na QFN, ƙwallon BGA, da hanyoyin lantarki masu ƙarfi.

Dalilan Fasaha:

• ·Masu saurin kama kwararar ruwa masu sauri
• ·Danshi a cikin abubuwan da ba a gasa ba na MSL 2a+
• ·Ta hanyar-in-pad ba tare da cika/rufewa ba
• ·Rashin kyawun jika

Mafita a Injiniya:

• ·Ƙimar tudu: 1.0–1.5°C/sec
• ·Kafin a gasa kowace J-STD-033
• ·Tashoshin da aka cika/an rufe
• ·Yi amfani da injin sake kwarara ko man shafawa mai ƙarancin voiding

6. Kai a cikin matashin kai (HIP)

Ma'anar: Mannewar ƙwallon BGA ta manna amma ta kasa haɗuwa.

Dalilan Fasaha:

• ·Rashin daidaito tsakanin Warpage
• ·Ƙwallon solder mai oxidized
• ·TAL ya yi gajere sosai

Mafita a Injiniya:

• ·Gasa BGAs: 125°C/awanni 12–24
• ·Yi amfani da kwararar ruwa tare da aiki ≥0.2%
• ·A ƙara TAL zuwa sama da 90s, a tabbatar da X-ray
• ·Inganta tarin bayanai don sarrafa shafin warpage

7. Solder Ball Splatter

Ma'anar: Ƙwallon da aka saka a cikin ƙananan ƙwayoyin halitta (

Dalilan Fasaha:

• ·Tsayin da ke da tsauri (>3°C/sec)
• ·Haɗin da ba ya daidaita: manna mai juyi
• ·Gurɓatar kushin
• ·Mannewa mai rauni na abin rufe fuska na solder

Mafita a Injiniya:

• ·Manna mara tsabta tare da resins masu ƙarfi
• ·Matattarar dumamawa: 1.0–1.5°C/sec zuwa 150–180°C
• ·A shafa tsaftace plasma
• ·A ƙayyade abin rufe fuska na solder tare da CTI > 175V

8. Ɗaga/Rage Faɗin Kushin

Ma'anar: Rabuwar kushin daga tushen PCB.

Dalilan Fasaha:

• ·Yawan sake yin aiki da zagaye
• ·Kayan CTE ko Tg mai ƙarancin axis na z
• ·Sha danshi

Mafita a Injiniya:

• ·Iyaka zuwa ≤2 zagayowar zafi a kowace kushin
• ·Yi amfani da kayan aikin sake fasalin thermocouple
• ·Gasa PCBs: 125°C/awanni 4–8 (IPC-1601)
• ·Yi amfani da laminates: Tg >170°C, Td >340°C

Rigakafin Lalacewar SMT na Tsari

• ·DFM: IPC-2581, Binciken Tsarin Ƙasa na IPC-7351B
• ·Dubawa: Tsarin SPI na Inline → AOI → AXI, KIC
• ·Kayan aiki: Gwajin SLP ga kowace IPC-J-STD-033, MSL
• ·Horarwa: Takardar shaidar IPC-A-610H, IPC-7711/7721

Cimma SMT mara lahani tare da Cikakken Farin Ciki

SMT mai aminci yana buƙatar ƙwarewa wajen hulɗar ƙira-tsari da kayan aiki. Cikakken Farin Ciki Mai Albarka, muna isar da PCBA mai mahimmanci ta hanyar:

• ·DFM da aka Inganta a Tsarin Aiki: Ra'ayoyin lokaci-lokaci tare da Valor NPI
• ·Binciken Ci gaba: 3D SPI, AOI mai amfani da AI, X-ray 5μm
• ·Babban Aminci na Taro: μBGA (0.2mm), void na QFN
• ·Bin diddigin abubuwa: Rijistar asalin iyali na matakin sassa

Tuntube mu don yin bita kyauta ta DFM da kuma binciken tsarin SMT.