Lub tshuab ua paug yog cov khoom tseem ceeb siv rau cov khoom siv roj hmab, thiab kho kom sov rau cov khoom siv roj hmab thiab cov tshuaj tua hluav taws xob muaj cov khoom siv hluav taws xob muaj cov khoom siv hauv qab no:
1. pulcanising roj hmab: kev siv roj hmab ntau dua, thiab siv roj hmab kom tiv thaiv, thiab cov roj hmab muaj pa tawm tau yooj yim, thiab siv cov roj hmab siab, lub sijhawm, thiab lwm yam tsis tau ua tiav txoj kev siv tshuaj phem ntawm cov roj hmab {{}}
{{02. Cov Khoom Siv Hluav Taws Xob: Cov Khoom Siv Hluav Taws Xob Ua Rau Cov Khoom Siv Cua Sov, Thiab yog li ntawm kev kho cov khoom siv kub, thiab yog li ntawm .
3.}} Tuam Txhab Kev Lag Luam, xws li muaj qhov kub thiab txias kom muaj zog, thiab li ntawm.
