1. Lub luj ntawm lub rooj tsavxwm nws tus kheej yuav ua rau lub rooj tsavxwm kev nyuaj siab deformation
Generalreflow qhov cubyuav siv cov saw hlau los tsav lub rooj tsavxwm rau pem hauv ntej, uas yog, ob sab ntawm lub rooj tsavxwm raws li ib tug fulcrum los txhawb tag nrho lub rooj tsavxwm.
Yog tias muaj qhov hnyav dhau ntawm lub rooj tsavxwm, lossis qhov loj ntawm lub rooj tsavxwm loj heev, nws yuav qhia qhov kev nyuaj siab hauv nruab nrab vim nws qhov hnyav, ua rau lub rooj tsavxwm khoov.
2. Qhov tob ntawm V-Cut thiab cov hlua txuas txuas yuav cuam tshuam rau qhov deformation ntawm lub rooj tsavxwm.
Yeej, V-Cut yog qhov ua txhaum ntawm kev rhuav tshem cov qauv ntawm lub rooj tsavxwm, vim tias V-Cut yog txiav cov grooves rau ntawm daim ntawv loj ntawm lub rooj tsavxwm, yog li V-Cut cheeb tsam yog feem ntau deformation.
Cov nyhuv ntawm cov khoom lamination, cov qauv thiab cov duab ntawm lub rooj tsavxwm deformation.
PCB pawg thawj coj saib yog ua los ntawm cov core board thiab semi-kho daim ntawv thiab txheej tooj liab ntawv xovxwm pressed ua ke, qhov twg lub core board thiab tooj liab ntawv ci yog deformed los ntawm tshav kub thaum nias ua ke, thiab tus nqi ntawm deformation nyob ntawm tus coefficient ntawm thermal expansion (CTE) ntawm ob yam khoom.
Lub coefficient ntawm thermal expansion (CTE) ntawm tooj liab ntawv ci yog hais txog 17X10-6;thaum lub Z-directional CTE ntawm zoo tib yam FR-4 substrate yog (50 ~ 70) X10-6 nyob rau hauv Tg point;(250 ~ 350) X10-6 saum TG point, thiab X-directional CTE feem ntau zoo ib yam li cov ntawv ci tooj liab vim muaj cov ntaub iav.
Deformation tshwm sim thaum lub sij hawm PCB board ua.
PCB board ua cov txheej txheem deformation ua rau nyuaj heev tuaj yeem muab faib ua thermal stress thiab mechanical stress los ntawm ob hom kev ntxhov siab.
Ntawm lawv, thermal stress yog tsim nyob rau hauv cov txheej txheem ntawm nias ua ke, txhua yam kev nyuaj siab yog tsuas yog generated nyob rau hauv lub board stacking, tuav, ci txheej txheem.Hauv qab no yog kev sib tham luv luv ntawm cov txheej txheem ua ntu zus.
1. Laminate cov khoom tuaj.
Laminate yog ob-sided, symmetrical qauv, tsis muaj duab, tooj liab ntawv ci thiab iav ntaub CTE tsis txawv ntau, yog li nyob rau hauv tus txheej txheem ntawm nias ua ke yuav luag tsis muaj deformation los ntawm txawv CTE.
Txawm li cas los xij, qhov loj ntawm laminate xovxwm thiab qhov kub ntawm qhov sib txawv ntawm qhov sib txawv ntawm cov phaj kub tuaj yeem ua rau qhov sib txawv me ntsis ntawm qhov ceev thiab qib ntawm resin curing nyob rau hauv ntau qhov chaw ntawm cov txheej txheem lamination, nrog rau qhov sib txawv loj ntawm dynamic viscosity. ntawm cov cua kub sib txawv, yog li tseem yuav muaj kev ntxhov siab hauv zos vim qhov sib txawv ntawm cov txheej txheem kho.
Feem ntau, qhov kev ntxhov siab no yuav khaws cia hauv qhov sib npaug tom qab lamination, tab sis yuav maj mam tso tawm hauv kev ua haujlwm yav tom ntej los tsim deformation.
2. Lamination.
PCB lamination txheej txheem yog cov txheej txheem tseem ceeb los ua kom muaj kev ntxhov siab thermal, zoo ib yam li laminate lamination, tseem yuav tsim kev ntxhov siab hauv zos los ntawm qhov sib txawv ntawm cov txheej txheem kho, PCB board vim thicker, graphic faib, ntau daim ntawv kho ib nrab, thiab lwm yam. nws cov thermal kev nyuaj siab kuj yuav nyuaj rau tshem tawm ntau tshaj li cov tooj liab laminate.
Cov kev ntxhov siab tam sim no nyob rau hauv lub rooj tsavxwm PCB raug tso tawm hauv cov txheej txheem tom ntej xws li drilling, shaping lossis grilling, uas ua rau deformation ntawm lub rooj tsavxwm.
3. Cov txheej txheem ci xws li solder tiv taus thiab ua cim.
Raws li solder tiv thaiv tus number case curing tsis tuaj yeem muab tso rau sab saum toj ntawm ib leeg, yog li PCB pawg thawj coj saib yuav muab tso rau hauv rack ci board curing, solder tiv taus kub ntawm li 150 ℃, tsuas yog saum toj no Tg taw tes ntawm cov khoom siv qis Tg, Tg point. saum toj no cov resin rau siab elastic xeev, lub rooj tsavxwm yog ib qho yooj yim rau deformation nyob rau hauv cov nyhuv ntawm tus kheej-qhov hnyav los yog muaj zog cua qhov cub.
4. Cua kub solder leveling.
Ordinary board kub cua solder leveling rauv kub ntawm 225 ℃ ~ 265 ℃, lub sij hawm rau 3S-6S.Cov cua kub kub ntawm 280 ℃ ~ 300 ℃ .
Solder leveling board los ntawm chav tsev kub rau hauv lub qhov cub, tawm ntawm lub cub tawg li ntawm ob feeb thiab tom qab ntawd chav tsev kub tom qab ua dej ntxuav.Tag nrho cov cua kub solder leveling txheej txheem rau tam sim ntawd kub thiab txias txheej txheem.
Vim tias cov khoom siv ntawm lub rooj tsavxwm sib txawv, thiab cov qauv tsis sib xws, hauv cov txheej txheem kub thiab txias yog khi rau thermal stress, uas ua rau micro-strain thiab tag nrho deformation warpage.
5. Cia.
PCB pawg thawj coj saib nyob rau theem ib nrab ntawm kev khaws cia yog feem ntau ntsug tso rau hauv lub txee, qhov kev hloov kho ntawm lub txee tsis tsim nyog, lossis cov txheej txheem khaws cia tso rau ntawm lub rooj tsavxwm yuav ua rau lub rooj tsavxwm txhua yam deformation.Tshwj xeeb tshaj yog rau 2.0mm hauv qab ntawm lub rooj tsavxwm nyias yog qhov hnyav dua.
Ntxiv rau qhov saum toj no, muaj ntau yam cuam tshuam rau PCB board deformation.
Post lub sij hawm: Sep-01-2022