Lub pwm los yog pwm yog lub thaiv uas muaj cov kua los yog cov khoom siv yas xws li yas, iav, hlau, los yog cov khoom siv los xij. Cov kua ua kom tawv los yog poob hauv cov pwm, siv nws cov duab. Lub pwm yog lub khauj khaum rau lub cam khwb cia. Cov txheej txheem siv ntau hom txheej txheem siv ob lub pwm, ib qho rau ib nrab ntawm cov khoom. Articulated molds muaj ntau daim uas tuaj ua ke los tsim kom tiav pwm, thiab ces disassemble tso tawm qhov tiav casting; lawv yog cov kim heev, tab sis tsim nyog thaum cov qauv casting tau muaj ntau lub cev. [qhov zoo tshaj qhov yuav tsum tau muaj] Vias-molding siv ntau lub pwm txawv, txhua tus tsim ib seem ntawm ib yam khoom nyuab. Qhov no tsuas yog siv rau cov khoom siv loj thiab tseem ceeb.
Lub khw tsim ua tuaj pwm hu ua "moldmaker". Tus neeg sawv cev tso tawm feem ntau yog siv los tshem tawm cov khoom sib tw / cov khoom tawm los ntawm cov pwm yooj yim. Cov kev siv rau cov yas molded muaj xws li cov ntaub moulded rooj tog, molded khoom vaj khoom tsev, cov ntaub molded, thiab cov ntaub ntawv cov khoom.