(2) Kev xav tau
Raws li kev ua tau zoo thiab kev pabcuam kev ua haujlwm ntawm lub khob ntawv, daim ntawv khob lub hauv paus ntawv yuav tsum muaj cov kev cai hauv qab no.
① Kev tiv thaiv dej siab
Lub khob ntawv luam ntawv yuav tsum tsis txhob muaj dej seepage thiab to, yog li cov ntawv khob hauv paus ntawv yuav tsum muaj dej tsis kam.
② Yooj yim rau txheej txheem
Thaum ua cov khob ntawv, kom tsis txhob muaj daim ntawv jamming thiab wrinkling thaum lub sij hawm tsim cov txheej txheem thiab tiv thaiv lub deformation ntawm daim ntawv khob tom qab molding, nws yuav tsum tau hais tias qhov nruj ntawm daim ntawv khob hauv paus ntawv yuav tsum siab, lub flatness yuav tsum zoo, cov txheej txheem luam ntawv yuav tsum zoo, qhov ntom thiab tuab yuav tsum yog nruab nrab, thiab nws yooj yim rau kev ua thiab cov duab.