Peb yuav tsum xyuam xim rau dab tsi thaum PBT txhaj tshuaj molding?

1. Txheej txheem yam ntxwv ntawm PBT
PBT muaj qhov pom tseeb melting point ntawm 225 ~ 235 degree. Nws yog cov khoom siv crystalline nrog crystallinity ntawm 40 feem pua.
Lub viscosity ntawm PBT yaj yog tsawg cuam tshuam los ntawm qhov kub thiab txias dua shear stress. Yog li ntawd, nyob rau hauv kev txhaj tshuaj molding, qhov cuam tshuam ntawm kev txhaj tshuaj siab ntawm fluidity ntawm PBT yaj yog pom tseeb.
PBT muaj fluidity zoo thiab tsis tshua muaj viscosity nyob rau hauv lub xeev molten, thib ob tsuas yog nylon, thiab nws yog "kab kab xev casting" thaum molding.
Anisotropy ntawm PBT molding khoom. PBT tau yooj yim degraded hauv dej ntawm qhov kub thiab txias.
2. Thaum xaiv cov ntsia hlau txhaj tshuaj molding tshuab, cov ntsiab lus hauv qab no yuav tsum tau xav txog.
① Cov khoom siv ntawm cov khoom siv yuav tsum tswj tsis pub dhau 30 feem pua ​​~ 80 feem pua ​​​​ntawm qhov ntsuas qhov siab tshaj plaws ntawm lub tshuab txhaj tshuaj molding. Nws tsis tsim nyog siv cov tshuab txhaj tshuaj loj loj los tsim cov khoom me me.
② Maj mam peb-theem ntsia hlau yuav tsum raug xaiv, nrog qhov ntev-inch piv ntawm 15 ~ 20 thiab compression piv ntawm 2.5 ~ 3.0.
③ Kev ntsuas tus kheej lub nozzle nrog cua sov thiab ntsuas kub yuav tsum raug xaiv.
④ Thaum tsim cov nplaim hluav taws-retardant PBT, qhov cuam tshuam ntawm lub tshuab txhaj tshuaj molding yuav tsum raug kho los tiv thaiv corrosion.
3. Khoom thiab pwm tsim
① Lub thickness ntawm cov khoom yuav tsum tsis txhob tuab heev, thiab PBT yog rhiab heev rau lub thais. Yog li ntawd, lub kaum sab xis thiab lwm yam kev hloov pauv ntawm cov khoom yuav tsum tau txuas nrog arc.
② Lub molding shrinkage ntawm unmodified PBT yog qhov loj, xws li 1.7 feem pua ​​​​rau 2.3 feem pua. Cov pwm yuav tsum muaj lub kaum sab xis tso tawm.
③ Cov pwm yuav tsum tau nruab nrog lub qhov tso tawm lossis cov qhov.
④ Txoj kab uas hla ntawm lub rooj vag yuav tsum loj.
⑤ Cov pwm yuav tsum tau nruab nrog cov cuab yeej tswj qhov kub thiab txias. Qhov siab tshaj plaws ntawm cov pwm yuav tsum tsis pub tshaj 100 degree.
⑥ nplaim retardant PBT molding, pwm nto yuav chrome plated los tiv thaiv corrosion.
4. Kev npaj cov khoom siv raw
Ua ntej txhaj tshuaj molding, qhuav thiab tswj cov dej noo hauv qab no 0.02 feem pua ​​. Thaum siv cov cua kub kom qhuav, thaum kub yog 105 degree, 120 degree lossis 140 degree, lub sijhawm sib xws yuav tsum tsis pub tshaj 6h, 4h thiab 2h. Cov khoom txheej thickness yog tsawg dua 30mm.
5. Kev txhaj tshuaj molding txheej txheem tsis
① Lub decomposition kub ntawm txhaj tshuaj kub PBT yog 280 degree, yog li nws yog feem ntau tswj ntawm 235 thiab 245 degree nyob rau hauv tiag tiag ntau lawm.
② Kev txhaj tshuaj siab Qhov kev txhaj tshuaj yog feem ntau 50 ~ 100MPa.
③ Tus nqi txhaj tshuaj PBT muaj qhov cua txias ceev, yog li yuav tsum tau txais kev txhaj tshuaj sai.
④ Cov ntsia hlau ceev thiab cov ntsia hlau ceev ntawm nraub qaum molding PBT yuav tsum tsis pub tshaj 80 r / min, feem ntau ntawm 25 thiab 60 r / min. Lub siab rov qab yog feem ntau 10% ~ 15 feem pua ​​​​ntawm kev txhaj tshuaj.
⑤ Cov pwm kub feem ntau tswj tau ntawm 70 ~ 80 degree, thiab qhov kub ntawm qhov sib txawv ntawm txhua qhov tsis ntau tshaj 10 degree.
⑥ Lub voj voog tsim feem ntau yog 15 ~ 60s.
teeb meem xav tau kev saib xyuas
① Qhov piv ntawm cov khoom siv rov qab rau cov khoom tshiab yog feem ntau 25 feem pua ​​~ 75 feem pua.
② Kev siv tus neeg tso tawm feem ntau tsis siv tus neeg tso tawm. Yog tias tsim nyog, silicone tso tawm tus neeg sawv cev tuaj yeem siv.
③ Lub sijhawm kaw ntawm PBT yog nyob rau hauv 30min, thiab nws tuaj yeem nres thaum qhov kub thiab txias txo mus rau 200 degree. Thaum qhov kev tsim khoom rov pib dua tom qab kaw lub sijhawm ntev, cov khoom siv hauv cov khoom siv yuav tsum tau muab pov tseg, thiab cov khoom siv tshiab tuaj yeem muab ntxiv rau kev tsim khoom ib txwm muaj.
④ Feem ntau, kev kho tom qab ntawm cov khoom tsis tas yuav tsum tau ua. Yog tias tsim nyog, kev kho mob yuav tsum tau ua ntawm 120 degree rau 1-2 teev.