Cia: Yog tias cov kav dej yuav tsum tau muab tso ua ke thiab khaws cia, lawv yuav tsum tsis txhob sib sau ntau dhau thiab yuav tsum tau muab tso rau hauv txoj kab ncaj nraim. Yog tias cov kav dej tsis tau muab tso ua ke kom zoo, cov kav dej yuav raug deformed; Qhov hnyav: Txawm hais tias cov kav dej PE yog sib dua li lwm cov kav dej ib txwm muaj, lawv tseem muaj qee yam khoom. Yog li ntawd, yuav tsum tau saib xyuas thaum tuav thiab tsim kho; unloading: yuav tsum tau siv cov chaw unloading kom raug, thiab tag nrho cov cuab yeej siv los tuav yuav tsum tau kuaj xyuas kom ua raws.
