Kev siv dav hauv cov khoom lag luam xws li cov khoom noj, tshuaj, txhua hnub - siv cov khoom, thiab cov ntawv ntim khoom, nrog rau cov txheej txheem extrusion rau cov khoom xws li cov duab thav duab, cov ntaub ntawv tsim kho, thiab cov ntawv pob tshab.
