Tsis tas li ntawd, cov tuam txhab tsim pwm kuj tuaj yeem muab faib ua cov pwm pwm raws li cov khoom pwm sib txawv: suav nrog stamping tuag, forging tuag, extrusion tuag, extrusion tuag, tuag-casting tuag, forging tuag, thiab lwm yam. non-metallic tuag tau muab faib ua: yas pwm thiab Inorganic non-metal pwm. Raws li cov khoom sib txawv ntawm pwm nws tus kheej, cov pwm tuaj yeem muab faib ua: xuab zeb pwm, hlau pwm, nqus pwm, paraffin pwm thiab lwm yam. Ntawm lawv, nrog rau kev loj hlob sai ntawm cov yas yas, cov pwm yas muaj feem xyuam nrog tib neeg lub neej. Cov pwm yas feem ntau tuaj yeem muab faib ua: txhaj tshuaj molding pwm, extrusion molding pwm, roj-pab pwm pwm, thiab lwm yam.