Cov ntaub ntawv raw yog thauj mus rau lub tshuab txhaj tshuaj molding, rhuab thiab melted, thiab ces txhaj rau hauv pwm rau molding. Tom qab txias, lawv raug tshem tawm los ntawm cov khoom noj mechanism thiab xa mus rau hauv qab dej los ntawm kev xa cov mechanism. Lawv tau nruab nrog kev tswj hwm, thiab qee qhov ntawm lawv muaj cov kev tshuaj xyuas zoo thiab cov khoom siv sau kom paub txog kev tsim khoom.