Thaum qhov kub ntawm lub siab Tg luam ntawv nce mus rau ib qho chaw, lub substrate yuav hloov los ntawm "iav xeev" mus rau "lub xeev roj hmab", thiab qhov kub ntawm lub sij hawm no hu ua lub iav hloov kub (Tg) ntawm lub rooj tsavxwm.

Hauv lwm lo lus, Tg yog qhov kub siab tshaj plaws (° C) uas lub substrate tswj rigidity. Qhov ntawd yog hais tias, cov ntaub ntawv zoo tib yam PCB substrate tsis tsuas yog tsim softening, deformation, melting thiab lwm yam tshwm sim nyob rau hauv high kub, tab sis kuj qhia ib tug ntse poob ntawm txhua yam thiab hluav taws xob yam ntxwv (Kuv xav tias koj tsis xav pom qhov no nyob rau hauv koj cov khoom). .

Feem ntau, Tg daim hlau yog siab dua 130 degrees, siab Tg feem ntau siab dua 170 degrees, thiab nruab nrab Tg yog li 150 degrees. Feem ntau cov PCB luam ntawv board nrog Tg≥: 170 ℃ yog hu ua siab Tg luam ntawv board. Tg ntawm lub substrate yog nce, thiab lub tshav kub tsis kam, noo noo tsis kam, tshuaj tiv thaiv, stability thiab lwm yam ntxwv ntawm lub board luam ntawv yuav raug txhim kho thiab txhim kho. Qhov siab dua TG tus nqi, qhov zoo dua qhov ntsuas kub ntawm lub rooj tsavxwm, tshwj xeeb tshaj yog nyob rau hauv cov txheej txheem tsis muaj txhuas, qhov siab Tg daim ntawv thov ntau dua. High Tg hais txog kev kub siab ua haujlwm.

Nrog rau txoj kev loj hlob sai ntawm kev lag luam hluav taws xob, tshwj xeeb tshaj yog cov khoom siv hluav taws xob uas sawv cev los ntawm cov khoos phis tawj, kev txhim kho ntawm kev ua haujlwm siab thiab siab multilayers yuav tsum muaj kev kub ntxhov siab dua ntawm cov khoom siv hauv PCB raws li qhov tseem ceeb lav.

Kev tshwm sim thiab kev loj hlob ntawm high-density mounting technology sawv cev los ntawm SMT.CMT tau ua PCBs ntau thiab ntau inseparable los ntawm kev txhawb nqa ntawm high kub kuj ntawm substrates nyob rau hauv cov nqe lus ntawm me me aperture, zoo Circuit Court thiab thinning. Yog li ntawd, qhov sib txawv ntawm qhov dav dav FR-4 thiab siab Tg FR-4: nws yog lub zog txhua yam, qhov ruaj khov, ruaj khov, adhesiveness, dej nqus, thiab thermal decomposition ntawm cov khoom nyob rau hauv lub xeev kub, tshwj xeeb tshaj yog thaum rhuab tom qab noo noo nqus. Muaj qhov sib txawv ntawm ntau yam xws li thermal expansion, siab Tg khoom yog pom tseeb zoo dua li cov khoom siv PCB substrate. Nyob rau hauv xyoo tas los no, tus naj npawb ntawm cov neeg siv khoom xav tau siab Tg cov ntawv luam tawm tau nce xyoo los ntawm xyoo.