1. Pwm kaw siab: Raws li txoj cai, nws yuav tsum siab tshaj qhov siab ntawm cov yas txhaj rau hauv pwm, tsis muaj burrs raws li qhov ntsuas.
2. Lub hom phiaj ntawm kev siv lub siab thiab ceev rau cov pwm yog los xyuas kom meej tias cov ntaub ntawv raw nkag mus rau hauv pwm tusyees, kom huv si, thiab tsim nyog, sau tag nrho cov ces kaum. Yog tias nws qis dhau, nws yuav ua rau luv luv, shrinkage, thiab yog tias nws siab dhau lawm, yuav muaj burrs, oversaturation, nplaum rau pwm, hlawv, yooj yim puas rau pwm, thiab siab sab hauv.
3. Qhov ceev txiav txim siab qhov xwm txheej ntawm cov khoom siv raw hauv cov pwm khiav thiab hauv cov khoom tiav. Yog tias muaj burrs, oversaturation, hlawv, thiab yog tias nws qeeb, kev txhaj tshuaj luv luv, shrinkage, thiab kev sib raug zoo tsis zoo yuav tshwm sim.
4. Qhov kub ntawm cov ntaub ntawv raw sib txawv, thiab yog tias cov kua nplaum melting tsawg dhau, nws yuav tsis muaj pob tshab, ua rau cov xim tsis sib xws thiab muaj kev ntxhov siab hauv cov khoom tiav. Yog hais tias qhov kub thiab txias yog siab dhau lawm, nws yuav ua rau cov ntsia hlau tawg. Yog tias nws siab dhau lawm, cov khoom yuav muaj burrs, thiab yuav muaj qhov sib txawv ntawm qhov kub thiab txias vim qhov txias, ua rau shrinkage. Cov khoom siv raw yuav decompose, tig daj, hloov xim, thiab nws yooj yim tawg. Lub sij hawm cua txias nce, ua rau nws nyuaj rau huab cua tawm.
