Hauv kev tsim khoom siv hluav taws xob niaj hnub no, SMT tau dhau los ua cov txheej txheem tseem ceeb rau kev sib dhos PCB. Tshwj xeeb tshaj yog rau ob - sab laug boards, ua kom tiav siab - cov txheej txheem ceev yuav tsum tau muab cov khoom siv hluav taws xob tso rau ntawm ob sab ntawm PCB. Txawm li cas los xij, ntau tus neeg yuav xav tias: tom qab thawj sab tau sib sau ua ke, yuav tsum tos ntev npaum li cas ua ntej sib sau ua ke ob sab?
Cia wb mus saib ntxiv. Lub sijhawm tos ua ntej sib sau ua ke ob sab feem ntau yog nyob ntawm qhov kev ua tau zoo ntawm cov tshuaj txhuam thiab ib puag ncig. solder paste yog cov khoom tseem ceeb tshaj plaws nyob rau hauv ob chav - sab sib dhos, vim nws tsis tsuas yog ruaj ntseg cov khoom ntawm PCB tab sis kuj muab cov hluav taws xob sib txuas thaum lub sij hawm reflow soldering. Nws cov dej num maj mam txo qis thaum lub sij hawm, thiab lub sij hawm ntev raug rau huab cua tuaj yeem ua rau oxidation lossis noo noo nqus, uas yuav cuam tshuam rau kev sib koom tes zoo. Feem ntau, rau cov hlau lead- dawb solder paste nyob rau hauv chav tsev kub, qhov thib ob - sab sib dhos yuav tsum ua kom tiav li ntawm 4 teev, thiab tsis pub dhau 8 teev. Rau cov khoom siv lead ua, lub qhov rais tuaj yeem ntev me ntsis, tab sis feem ntau nws pom zoo kom ua tiav hauv 6 teev.
Dhau li ntawm solder paste, kev sib dhos ua ntu zus thiab cov khoom siv kuj tseem ceeb heev. Lub teeb thiab cov khoom me me, xws li 0201 lossis 0402 pob, feem ntau yog muab tso rau ntawm lub teeb, thaum cov khoom loj lossis hnyav dua raug pom zoo kom muab tso rau hauv qab ntawm PCB los tiv thaiv lawv los ntawm kev poob tawm thaum lub sij hawm rov qab thib ob. Hauv kev tsim khoom tiag tiag, cov kab ke ib txwm yog: hauv qab - sab tso → reflow soldering → sab saum toj - sab tso → thib ob reflow. Xyuas kom meej tias sab thib ob yog sib sau ua ke nyob rau hauv lub sij hawm nquag ntawm cov tshuaj txhuam hniav tuaj yeem txo qhov tsis xws luag xws li cov voids, cov khoom siv, lossis cov pob qij txha txias, txhim kho ob qho tib si tawm los thiab kev ntseeg tau ntawm cov khoom.
