1. Keeb kwm
Wave soldering yog thov thiab rhuab los ntawm molten solder rau cov pins ntawm cov khoom.Vim yog qhov txheeb ze ntawm yoj crest thiab PCB thiab "stickiness" ntawm molten solder, cov txheej txheem yoj soldering yog ntau nyuaj tshaj li reflow vuam.Muaj qhov yuav tsum tau ua rau tus pin sib nrug, tus pin ncua ntev thiab ncoo loj ntawm pob yuav tsum tau welded.Kuj tseem muaj qhov yuav tsum tau ua rau kev taw qhia layout, qhov sib nrug thiab kev sib txuas ntawm qhov txuas ntawm lub PCB board nto.Hauv ib lo lus, cov txheej txheem ntawm yoj soldering yog qhov tsis zoo thiab yuav tsum tau ua kom zoo.Cov txiaj ntsig ntawm welding yeej nyob ntawm kev tsim.
2. Ntim cov cai
ib.Mount Cheebtsam haum rau yoj soldering yuav tsum muaj vuam xaus los yog ua tiav raug;Pob lub cev hauv av clearance (Sawv tawm) <0.15mm;Qhov siab <4mm qhov yuav tsum tau ua.
Mount cov ntsiab lus uas ua tau raws li cov xwm txheej no suav nrog:
0603 ~ 1206 nti tsis kam thiab capacitance ntsiab nyob rau hauv lub pob loj ntau yam;
SOP nrog lead center nrug ≥1.0mm thiab qhov siab <4mm;
Chip inductor nrog qhov siab ≤4mm;
Tsis-exposed coil nti inductor (hom C, M)
b.Lub compact pin haum haum rau yoj soldering yog lub pob nrog qhov tsawg kawg nkaus ntawm qhov nyob ib sab pins ≥1.75mm.
[Cov Lus Qhia]Qhov tsawg kawg nkaus qhov sib txawv ntawm cov khoom siv ntxig yog qhov tsim nyog rau kev siv nthwv dej.Txawm li cas los xij, ua tau raws li qhov yuav tsum tau muaj qhov sib nrug tsawg kawg tsis tau txhais hais tias kev vuam zoo tuaj yeem ua tiav.Lwm qhov yuav tsum tau muaj xws li kev taw qhia kev teeb tsa, qhov ntev ntawm cov hlau lead tawm ntawm qhov chaw vuam, thiab qhov sib txawv ntawm lub ncoo yuav tsum tau ua tiav.
Chip mount caij, pob loj <0603 tsis haum rau yoj soldering, vim hais tias qhov sib txawv ntawm ob kawg ntawm lub caij yog me me heev, yooj yim tshwm sim ntawm ob kawg ntawm tus choj.
Chip mount caij, pob loj> 1206 tsis haum rau yoj soldering, vim yoj soldering yog tsis sib npaug cua sov, loj loj nti kuj thiab capacitance caij yog ib qho yooj yim rau tawg vim thermal expansion mismatch.
3. Kev taw qhia kis tau tus mob
Ua ntej kev teeb tsa ntawm cov khoom ntawm cov nthwv dej saum npoo, kev hloov pauv ntawm PCB los ntawm lub qhov cub yuav tsum tau txiav txim siab ua ntej, uas yog "tus txheej txheem siv" rau kev teeb tsa ntawm cov khoom ntxig.Yog li ntawd, cov kev taw qhia ntawm kev sib kis yuav tsum tau txiav txim siab ua ntej lub layout ntawm cov khoom nyob rau hauv lub yoj soldering nto.
ib.Feem ntau, cov kev taw qhia kis tau tus mob yuav tsum yog sab ntev.
b.Yog hais tias lub layout muaj ib tug tuab pin insert connector (spacing <2.54mm), layout kev taw qhia ntawm lub connector yuav tsum yog cov kev taw qhia kis tau tus mob.
c.Nyob rau ntawm lub nthwv dej ntawm qhov chaw, silk screen lossis tooj liab ntawv etched xub yog siv los cim cov kev taw qhia ntawm kev xa mus rau kev txheeb xyuas thaum vuam.
[Cov Lus Qhia]Cov txheej txheem txheej txheem yog ib qho tseem ceeb heev rau yoj soldering, vim yoj soldering muaj cov txheej txheem tin hauv thiab tin tawm.Yog li ntawd, tsim thiab vuam yuav tsum nyob rau hauv tib txoj kev.
Qhov no yog vim li cas rau kos cov kev taw qhia ntawm yoj soldering kis tau tus mob.
Yog tias koj tuaj yeem txiav txim siab qhov kev taw qhia ntawm kev sib kis, xws li kev tsim cov khoom siv hluav taws xob uas raug nyiag lawm, cov kev taw qhia ntawm kev sib kis tsis tuaj yeem txheeb xyuas tau.
4. Cov kev taw qhia layout
Cov kev taw qhia layout ntawm cov khoom feem ntau suav nrog cov chips thiab ntau tus pin connectors.
ib.Cov kev taw qhia ntev ntawm LUB PACKAGE ntawm SOP cov cuab yeej yuav tsum tau teem caij mus rau qhov sib npaug ntawm cov kev taw qhia ntawm nthwv dej ncov vuam, thiab cov kev taw qhia ntev ntawm cov khoom siv chip yuav tsum yog perpendicular mus rau qhov kev taw qhia ntawm yoj peak vuam.
b.Rau ntau yam ob-pin plug-in Cheebtsam, cov kev taw qhia kev sib txuas ntawm lub jack center yuav tsum yog nyob rau hauv perpendicular mus rau lub kis tau tus mob kev taw qhia kom txo tau lub floating phenomenon ntawm ib kawg ntawm cov khoom.
[Cov Lus Qhia]Vim hais tias lub pob lub cev ntawm thaj chaw muaj kev cuam tshuam ntawm cov molten solder, nws yog ib qho yooj yim uas yuav ua rau cov xau vuam ntawm cov pins tom qab pob lub cev (sab destin).
Yog li ntawd, cov kev cai dav dav ntawm lub cev ntim tsis cuam tshuam rau cov kev taw qhia ntawm kev khiav ntawm molten solder layout.
Kev sib txuas ntawm ntau tus pin connectors tshwm sim feem ntau ntawm de-tinning kawg / sab ntawm tus pin.Alignment ntawm connector pins nyob rau hauv cov kev taw qhia ntawm kis tau tus mob txo tus naj npawb ntawm detinning pins thiab, thaum kawg, tus naj npawb ntawm Choj.Thiab tom qab ntawd tshem tawm tus choj tag nrho los ntawm kev tsim cov tin pad uas raug nyiag lawm.
5. Qhov yuav tsum tau sib nrug
Rau thaj thaj chaw, qhov sib txawv ntawm lub ncoo yog hais txog qhov sib nrug ntawm qhov siab tshaj plaws overhang nta (nrog rau cov ntaub qhwv) ntawm cov pob khoom uas nyob ib sab;Rau cov khoom siv plug-in, pad spacing yog hais txog qhov sib nrug ntawm cov ntaub qhwv.
Rau SMT Cheebtsam, qhov sib txawv ntawm lub ncoo tsis yog tsuas yog txiav txim siab los ntawm tus choj nam, tab sis kuj suav nrog kev cuam tshuam ntawm lub pob lub cev uas tuaj yeem ua rau vuam to.
ib.Pad qhov sib nrug ntawm cov khoom siv plug-in feem ntau yuav tsum yog ≥1.00mm.Rau qhov zoo-pitch plug-in connectors, kev txo qis yog tso cai, tab sis qhov tsawg kawg nkaus yuav tsum tsis pub tsawg tshaj 0.60mm.
b.Lub ncua sij hawm ntawm lub ncoo ntawm plug-in Cheebtsam thiab lub ncoo ntawm yoj soldering thaj Cheebtsam yuav tsum yog ≥1.25mm.
6. Cov kev cai tshwj xeeb rau kev tsim lub ncoo
ib.Txhawm rau txo cov vuam xau, nws raug nquahu kom tsim cov ntaub qhwv rau 0805/0603, SOT, SOP thiab tantalum capacitors raws li cov hauv qab no.
Rau 0805/0603 Cheebtsam, ua raws li kev pom zoo tsim ntawm IPC-7351 (pad nthuav dav los ntawm 0.2mm thiab dav txo los ntawm 30%).
Rau SOT thiab tantalum capacitors, pads yuav tsum tau ncua 0.3 hli sab nraud tshaj li cov qauv tsim.
b.rau lub qhov metallized lub phaj, lub zog ntawm qhov sib koom ua ke feem ntau yog nyob ntawm qhov sib txuas, qhov dav ntawm lub nplhaib ncoo ≥0.25mm.
c.Rau cov qhov uas tsis yog xim hlau (ib lub vaj huam sib luag), lub zog ntawm qhov sib koom ua ke yog nyob ntawm qhov loj ntawm lub ncoo, feem ntau lub taub ntawm lub ncoo yuav tsum ntau dua 2.5 npaug ntawm qhov aperture.
d.Rau SOP ntim, tin tub sab ncoo yuav tsum tau tsim ntawm tus pin kawg.Yog tias qhov sib txawv ntawm SOP yog qhov loj, tin tub sab pad tsim tuaj yeem loj dua.
e.rau lub multi-pin connector, yuav tsum tau tsim nyob rau hauv lub tin kawg ntawm lub tin ncoo.
7. coj ntev
a.Qhov ntev ntawm cov hlau lead muaj kev sib raug zoo nrog kev tsim ntawm kev sib txuas ntawm tus choj, qhov me me ntawm qhov sib txawv ntawm tus pin, qhov cuam tshuam ntau dua.
Yog hais tias tus pin sib nrug yog 2 ~ 2.54 hli, cov hlau lead ntev yuav tsum tau tswj hauv 0.8 ~ 1.3 hli
Yog tias qhov sib nrug ntawm tus pin tsawg dua 2 hli, qhov ntev ntawm cov hlau lead yuav tsum tau tswj hauv 0.5 ~ 1.0mm
b.Qhov kev ncua ntev ntawm cov hlau lead tuaj yeem tsuas yog ua lub luag haujlwm nyob rau hauv cov xwm txheej uas qhov kev taw qhia layout ua tau raws li qhov yuav tsum tau ua ntawm yoj soldering, txwv tsis pub cov nyhuv ntawm kev tshem tawm choj tsis pom tseeb.
[Cov Lus Qhia]Kev cuam tshuam ntawm cov hlau lead ntev ntawm kev sib txuas ntawm tus choj yog qhov nyuaj dua, feem ntau> 2.5mm lossis <1.0mm, qhov cuam tshuam ntawm kev sib txuas ntawm tus choj yog me me, tab sis ntawm 1.0-2.5m, lub zog kuj loj heev.Ntawd yog, nws feem ntau yuav ua rau muaj qhov tshwm sim txuas ntxiv thaum nws tsis ntev lossis luv dhau.
8. Daim ntawv thov ntawm vuam number case
ib.Peb feem ntau pom ib co connector ncoo graphics luam ink graphics, xws li ib tug tsim feem ntau ntseeg hais tias yuav txo tau cov bridging tshwm sim.Cov txheej txheem yuav yog qhov saum npoo ntawm tus number case txheej yog ntxhib, yooj yim rau nqus ntau flux, flux nyob rau hauv kub kub molten solder volatilization thiab tsim ntawm kev sib cais npuas, thiaj li yuav txo tau qhov tshwm sim ntawm bridging.
b.Yog tias qhov kev ncua deb ntawm tus pin pads <1.0mm, koj tuaj yeem tsim cov txheej txheem thaiv cov kua nplaum sab nraum lub ncoo kom txo tau qhov tshwm sim ntawm kev sib txuas, nws yog qhov tseem ceeb kom tshem tawm cov ntaub qhwv ntom ntom hauv nruab nrab ntawm tus choj ntawm cov pob qij txha, thiab lub ntsiab. tshem tawm ntawm pawg tuab tuab ntawm qhov kawg ntawm tus choj solder sib koom ua ke lawv cov haujlwm sib txawv.Yog li ntawd, rau tus pin ncua yog qhov me me ntom ntom ntom ntom ntom, ham number case thiab nyiag sad cawb ncoo yuav tsum tau siv ua ke.
Post lub sij hawm: Nov-29-2021