Cov txheej txheem ntawm cov hlau lead-dawb reflow soldering muaj ntau dua cov kev xav tau ntawm PCB dua li cov txheej txheem txhuas.Lub tshav kub tsis kam ntawm PCB yog qhov zoo dua, lub iav hloov pauv kub Tg siab dua, thermal expansion coefficient tsawg, thiab tus nqi qis.
Lead-free reflow soldering yuav tsum tau rau PCB.
Hauv reflow soldering, Tg yog cov cuab yeej tshwj xeeb ntawm polymers, uas txiav txim siab qhov kub thiab txias ntawm cov khoom siv.Thaum lub sij hawm SMT soldering txheej txheem, qhov kub ntawm soldering yog ntau dua li Tg ntawm PCB substrate, thiab cov hlau lead-free soldering kub yog 34 ° C siab dua li cov hlau lead, uas ua rau nws yooj yim rau thermal deformation ntawm PCB thiab puas. rau cov khoom thaum lub caij txias.Cov khoom siv hauv PCB nrog Tg siab dua yuav tsum tau xaiv kom raug.
Thaum lub sij hawm vuam, yog tias qhov kub thiab txias nce, Z-axis ntawm cov txheej txheem multilayer PCB tsis phim CTE ntawm cov khoom siv laminated, iav fiber, thiab Cu hauv XY kev taw qhia, uas yuav ua rau muaj kev ntxhov siab ntau ntawm Cu, thiab hauv mob hnyav, nws yuav ua rau lub plating ntawm lub qhov metallized tawg thiab ua rau vuam tsis xws luag.Vim nws nyob ntawm ntau qhov sib txawv, xws li PCB txheej tooj, thickness, laminate khoom, soldering nkhaus, thiab Cu tis, ntawm geometry, thiab lwm yam.
Hauv peb qhov kev ua haujlwm tiag tiag, peb tau siv qee qhov kev ntsuas kom kov yeej qhov tawg ntawm lub qhov metallized ntawm lub rooj tsavxwm multilayer: piv txwv li, cov resin / iav fiber ntau raug tshem tawm hauv lub qhov ua ntej electroplating hauv cov txheej txheem recess etching.Txhawm rau ntxiv dag zog rau kev sib raug zoo ntawm cov phab ntsa metallized qhov thiab cov txheej txheem ntau txheej.Qhov tob etch yog 13 ~ 20µm.
Qhov ntsuas kub ntawm FR-4 substrate PCB yog 240 ° C.Rau cov khoom siv yooj yim, lub ncov kub ntawm 235 ~ 240 ° C tuaj yeem ua tau raws li qhov yuav tsum tau ua, tab sis rau cov khoom siv, nws yuav xav tau 260 ° C los ua kom sov.Yog li ntawd, cov phaj tuab thiab cov khoom siv nyuaj yuav tsum tau siv cov khoom kub FR-5.Vim tias tus nqi ntawm FR-5 yog qhov siab, rau cov khoom siv zoo tib yam, cov khoom sib xyaw CEMn tuaj yeem siv los hloov FR-4 substrates.CEMn yog lub hauv paus tsis sib xyaw tooj liab-clad laminate uas nws nto thiab cov tub ntxhais yog ua los ntawm cov khoom sib txawv.CEMn rau luv luv sawv cev rau cov qauv sib txawv.
Post lub sij hawm: Lub Xya hli ntuj-22-2023