Cov Kev Tsis Zoo thiab Kev Dais Teeb Meem ntawm SMT: Ib Daim Ntawv Qhia Tag Nrho rau Kev Sib Dhos PCB Txhim Khu Kev
Vim li cas SMT Txheej Txheem Kev Tswj Xyuas Qhov Tsis Zoo yog Qhov Tseem Ceeb
Kev Siv Tshuab Ncej (SMT) xav tau qhov kev ua kom raug ntawm qib micron hauv kev tso cov tshuaj nplaum, kev tso cov khoom, thiab kev tswj hwm thermal. Kev hloov pauv hauv kev tsim stencil, qhov ntim ntawm cov tshuaj nplaum solder, lossis cov qauv rov ua dua tuaj yeem ua rau muaj qhov tsis zoo uas ua rau cov khoom tsis ntseeg tau - tshwj xeeb tshaj yog hauv kev tsim cov khoom siv high-density, high-speed, lossis multilayer. Rau cov ntawv thov aerospace, automotive, medical, thiab telecom, cov qhov tsis zoo SMT uas tsis pom yuav ua rau muaj kev puas tsuaj loj heev. Phau ntawv qhia no piav qhia txog cov qhov tsis zoo SMT, lawv cov hauv paus, thiab kev daws teeb meem engineering.
1. Kev Ua Pob Zeb Rau Tombstone (Manhattan Effect)
Kev Txhais Lus: Ib qho khoom siv chip (piv txwv li, 0201/0402) tsa ntsug thaum lub sijhawm rov ua dua, sib cais ntawm ib lub ncoo.
Cov laj thawj kev txawj ntse:
- ·Qhov ntim ntawm cov khoom sib xyaw tsis sib npaug ntawm cov ntaub qhwv ua ke
- ·Qhov hnyav thermal tsis sib xws (piv txwv li, qhov dav tsis sib npaug lossis nchuav tooj liab)
- ·Kev hloov pauv ntau dhau ntawm qhov nrawm (> 2 ° C / sec)
- ·Kev tsim qauv qhov aperture uas tsis zoo
- ·Cov qauv geometry ntawm lub ncoo ua txhaum cov cai ntawm IPC-7351 symmetry
Kev daws teeb meem engineering:
- ·Tsim cov ntaub qhwv / cov kab sib luag ib qho IPC-7351B cov lus qhia
- ·Sib phim qhov loj me ntawm lub qhov (stencil aperture sizes/volumes) rau cov khoom siv xaus (component terminations)
- ·Txwv qhov nrawm ntawm kev rov ua dua tshiab rau 1–2°C/sib
- ·Siv qhov aperture overprint (rau ≤01005 passives)
- ·Tsis txhob muab cov khoom tso ze ntawm cov dav hlau tooj liab loj
2. Kev Txuas Txuas
Kev Txhais Lus: Kev sib txuas tsis xav tau ntawm cov xov hlau / cov ntaub qhwv uas nyob ib sab.
Cov laj thawj kev txawj ntse:
- ·Cov qhov loj ntawm stencil loj dhau los yog cov ntim nplaum ntau dhau
- ·Tsis txaus lub npog ntsej muag solder (
- ·Kev tso tawm cov nplaum tsis zoo (piv txwv li, qhov sib piv ntawm stencil tsis txaus)
- ·Kev tsis sib haum xeeb thaum lub sijhawm luam ntawv stencil
Kev daws teeb meem engineering:
- ·Siv cov kev txo qhov aperture (piv txwv li, "dog-bone" rau QFPs, "home-plate" rau BGAs)
- ·Txhim kho qhov sib piv ntawm qhov aperture (≥1.5) thiab thaj chaw piv (≥0.66)
- ·Qhia kom meej qhov dav ntawm lub npog ntsej muag solder ≥0.025mm rau cov qauv tsim zoo nkauj
- ·Tso Tawm Kev Tshuaj Xyuas Cov Tshuaj Nplaum 3D (SPI)
- ·Siv cov txheej txheem ntxuav stencil
3. Tsis Txaus Cov Khoom Siv Txuas (Tsis-Ntxhov/Qhib Cov Pob Qij Txha)
Kev Txhais Lus: Kev sib txuas hlau tsis tiav vim tsis muaj cov khoom siv solder txaus.
Cov laj thawj kev txawj ntse:
- ·Tsis txaus cov tshuaj nplaum
- ·Qhov profile reflow tsis zoo (qhov kub siab tshaj plaws lossis TAL)
- ·Kev ua kom tawv nqaij/khoom sib xyaw ua ke
- ·Cov tshuaj nplaum qhuav thaum lub sijhawm ntev raug tshav ntuj
Kev daws teeb meem engineering:
- ·Kev kho kom rov qab zoo dua: Qhov kub siab tshaj plaws yog 240–245°C, TAL yog 60–90 vib nas this
- ·Siv Hom 4/5 nplaum
- ·Qhia meej IB ZAUG / IB ZAUG TAG NRHO
- ·Tswj qhov chaw luam ntawv: 25 ± 3 ° C, 40–60% RH
4. Kev Hloov Pauv/Kev Tsis Sib Haum ntawm Cheebtsam
Kev Txhais Lus: Kev hloov pauv ntawm cov khoom thaum lub sijhawm rov ua dua.
Cov laj thawj kev txawj ntse:
- ·Cov tshuaj nplaum tsis zoo
- ·Cov teeb meem ntawm kev co / convection ntawm lub conveyor
- ·Lub zog ntawm lub nozzle tsis raug/qhov siab z
- ·PCB warpage ze Tg
Kev daws teeb meem engineering:
- ·Lub zog nplaum nplaum > 500g/mm²
- ·Calibrate pick-and-place: ≤30μm qhov tseeb, 0.2–0.5N zog
- ·Tswj qhov ceev ntawm lub kiv cua thiab kev co ntawm lub tshuab nqa khoom
- ·Siv FR-4 Tg170+ los yog kev txhawb nqa khoom siv
5. Cov Voids Sib Koom Tes
Kev Txhais Lus: Kev ntes roj ua rau muaj qhov hauv cov pob qij txha.
Cov Cheeb Tsam Muaj Kev Pheej Hmoo Siab: QFN thermal pads, BGA pob, high-current vias.
Cov laj thawj kev txawj ntse:
- ·Cov khoom siv hluav taws xob uas ntes tau cov dej phwj sai
- ·Cov dej noo hauv cov khoom MSL 2a+ uas tsis tau ci
- ·Via-in-pad tsis muaj sau / capping
- ·Kev ua luam dej tsis zoo
Kev daws teeb meem engineering:
- ·Tus nqi nce toj: 1.0–1.5°C/sec
- ·Ua ntej ci ib J-STD-033
- ·Cov qhov dej puv/kaw
- ·Siv lub tshuab nqus tsev vacuum reflow los yog cov tshuaj nplaum uas tsis muaj dej ntau
6. Lub Taub Hau Hauv Lub Hauv ncoo (HIP)
Kev Txhais Lus: BGA pob contacts sib xyaw tab sis tsis sib koom ua ke.
Cov laj thawj kev txawj ntse:
- ·Kev sib txawv ntawm nplooj ntawv tsis sib xws
- ·Cov pob oxidized solder
- ·TAL luv dhau
Kev daws teeb meem engineering:
- ·Bake BGAs: 125°C/12–24 teev
- ·Siv cov kua dej uas muaj ≥0.2% kev ua haujlwm
- ·Txuas ntxiv TAL mus rau >90s, xyuas kom meej nrog X-ray
- ·Txhim kho stackup rau kev tswj hwm warpage
7. Cov Pob Sib Txuas
Kev Txhais Lus: Cov pob me me (
Cov laj thawj kev txawj ntse:
- ·Nce toj siab (>3°C/sec)
- ·Cov hlau tsis sib xws: flux paste
- ·Kev ua qias tuaj ntawm cov ntaub pua plag
- ·Lub ntsej muag tsis muaj zog lo rau
Kev daws teeb meem engineering:
- ·Cov tshuaj nplaum tsis huv nrog cov resins ruaj khov
- ·Ua ntej cua sov: 1.0–1.5°C/sec txog 150–180°C
- ·Siv cov tshuaj ntxuav plasma
- ·Qhia kom meej lub npog ntsej muag nrog CTI > 175V
8. Kev Tshem Tawm/Kev Tshem Tawm Cov Ncej
Kev Txhais Lus: Kev sib cais ntawm lub hauv paus PCB.
Cov laj thawj kev txawj ntse:
- ·Kev ua haujlwm rov ua dua ntau dhau
- ·Cov khoom siv CTE lossis Tg qis z-axis
- ·Kev nqus dej noo
Kev daws teeb meem engineering:
- ·Txwv rau ≤2 lub voj voog cua sov ib daim ntaub
- ·Siv cov cuab yeej kho dua tshiab uas tswj tau los ntawm thermocouple
- ·Cov PCBs: 125°C/4–8 teev (IPC-1601)
- ·Siv cov laminates: Tg > 170 ° C, Td > 340 ° C
Kev Tiv Thaiv Qhov Tsis Zoo ntawm SMT
- ·DFM: IPC-2581, IPC-7351B kev kuaj xyuas cov qauv av
- ·Kev Tshuaj Xyuas: Inline SPI → AOI → AXI, KIC qhov cub profiling
- ·Khoom siv: MSL ib IPC-J-STD-033, kev kuaj SLP
- ·Kev Kawm: IPC-A-610H, daim ntawv pov thawj IPC-7711/7721
Ua tiav qhov tsis zoo ntawm SMT nrog kev xyiv fab puv npo
SMT txhim khu kev qha yuav tsum muaj kev paub txog kev sib cuam tshuam ntawm cov khoom siv-txheej txheem-kev tsim qauv. Kev Xyiv Fab Tag Nrho, peb xa cov PCBA tseem ceeb los ntawm:
- ·DFM uas Zoo Rau Cov Txheej Txheem: Cov lus teb tiag tiag nrog Valor NPI
- ·Kev Tshuaj Xyuas Siab Tshaj: 3D SPI, AI-powered AOI, 5μm X-ray
- ·Kev Sib Dhos Zoo Siab: μBGA (0.2 hli), QFN voiding
- ·Kev taug qab tau: Kev sau cov ntaub ntawv keeb kwm ntawm theem Cheebtsam
Tiv tauj peb rau kev tshuaj xyuas DFM dawb thiab kev tshuaj xyuas cov txheej txheem SMT.
