1) Cov khoom siv raw nws tus kheej tsis zoo hauv cov xim thiab qhov ci, thiab nws tau hloov tom qab ua plasticized ntawm qhov kub.
(2) Kev pab cuam lub neej ntawm cov khoom siv tiv thaiv ntev dhau lawm, ua rau kev laus ntawm cov ntswj ntsia hlau, lub peev xwm ua tsis tau zoo, thiab hloov xim
(3) Kev tswj tsis tau kub tsis txaus ua rau cov cuab yeej ua rau lub ntsuas kub hauv cheeb tsam siab dhau. Nws raug nquahu kom hloov cov thermocouple tshiab thiab kho qhov kub ntawm cheeb tsam tswj cov ntaub ntawv hloov kho kom raws sijhawm.
(4) Tom qab cov khoom seem dhau ntawm kev tsim cov yas ntim khoom yog tsoo, qhov sib piv ntawm impurities mus rau cov ntaub ntawv raw yog qhov loj heev, ua rau muaj kev hloov xim.
