Annealing
Vim tsis sib xwsplasticizationlos yog tsis sib xws crystallization, kev taw qhia, thiab cua txias ntawm cov yas hauv cov pwm kab noj hniav, qhov sib txawv shrinkage tshwm sim nyob rau ntau qhov chaw ntawm cov yas. Tsis tas li ntawd, kev cuam tshuam ntawm cov hlau ntxig thiab kev ua haujlwm tsis zoo ntawm cov yas inevitably ua rau muaj kev ntxhov siab sab hauv. Lub xub ntiag ntawm kev ntxhov siab sab hauv feem ntau ua rau deformation lossis tawg thaum siv, yog li ntawd, annealing feem ntau yuav tsum tau tshem tawm cov kev ntxhov siab seem.
Txoj kev annealing yuav tsum muab cov yas tso rau hauv qhov cub ntawm qhov kub thiab txias los yog hauv cov kua nruab nrab (xws li dej, kub ntxhia roj, glycerin, ethylene glycol, thiab kua paraffin) rau ib lub sij hawm, tom qab ntawd maj mam txias mus rau chav sov. Lub tshav kub generated thaum lub sij hawm annealing accelerates lub so ntawm macromolecules nyob rau hauv cov yas, yog li tshem tawm los yog txo cov residual kev nyuaj siab tom qab molding.
Annealing kub yog feem ntau tswj ntawm 10-20℃saum toj no qhov kev pab cuam kub ntawm cov yas los yog 10-20℃hauv qab lub tshav kub distortion kub ntawm cov yas.
Qhov kub yuav tsum tsis txhob siab dhau, txwv tsis pub cov yas yuav warp; qhov kub thiab txias yuav tsum tsis txhob qis dhau, txwv tsis pub lub hom phiaj ntawm kev tshaj tawm - kev kho mob yuav tsis ua tiav.
Lub sij hawm annealing nyob ntawm yam xws li hom yas, qhov kub thiab txias ntawm cov cua sov nruab nrab, cov duab thiab phab ntsa thickness ntawm cov yas, thiab cov precision yuav tsum tau ntawm cov yas. Table 2-6 qhia txog kev kho cua sov rau cov thermoplastics uas nquag siv.
Table 2-6 Common Kub Khiav Moulding Txheej Txheem rau Thermoplastics
| Khoom siv | Kev ntsuas kub (degree) | Lub sijhawm (h) | Txoj Kev Kub Kub |
|---|---|---|---|
| ABS | 70 | 4 | Qhov cub |
| Polyoxymethylene (POM) | 110 ~ 135 | 4 ~ 8 | Qhov cub |
| 100 ~ 110 | 8 ~ 12 | Far-infrared teeb, Qhov cub | |
| Polyamide (PA / Nylon) | 140 ~ 145 | 4 | Far-infrared cua sov, Qhov cub |
| Polyurethane (TPU) | 100 ~ 110 | 4 | Ntsev da dej |
| Tom ntej: Polymethylmethacrylate (PMMA) | 70 | 4 | Far-infrared cua sov, Qhov cub |
| Polycarbonate (PC) | 110 ~ 130 | 4 ~ 8 | Far-infrared cua sov, Qhov cub, roj da dej |
| Polyethylene terephthalate (PET) | 120 | 1 ~ 2 | Qhov cub |
Humidity txias
Conditioning yuav tsum muab cov yas demolded freshly demolded nyob rau hauv dej kub kom cais lawv los ntawm huab cua, tiv thaiv oxidation, tshem tawm kev ntxhov siab nyob rau hauv, thiab ceev kom ncav cuag ntawm noo noo equilibrium, yog li stabilizing lawv qhov ntev. Piv txwv li, cov khoom yas polyamide yog nquag oxidation thiab discoloration thaum raug huab cua kub tom qab demolding, thiab yooj yim nqus ya raws thiab nthuav thaum siv los yog khaws cia hauv huab cua. Conditioning cais lawv ntawm huab cua thiab tso cai rau lawv kom sai li sai tau mus cuag noo noo equilibrium, stabilizing lawv qhov ntev.
Kev txias txias tuaj yeem txhim kho qhov tawv ntawm cov khoom yas, ua rau muaj kev cuam tshuam toughness thiab tensile lub zog. Qhov ntsuas kub yog feem ntau 100-120 degree; rau cov yas uas muaj qhov kub thiab txias distortion, qhov txwv sab saud yog siv; conversely, qhov kev txwv qis yog siv.
Lub sijhawm txias yog nyob ntawm hom yas, qhov zoo ntawm qhov, nws cov phab ntsa thickness, thiab nws cov crystallinity. Tom qab lub sijhawm txias tau mus txog, cov khoom yog maj mam txias mus rau chav sov.