1. Qhov kub ua haujlwm siab, qhov siv siab kub yog 650-1000 ℃;
2. Nrog rau qhov kub thiab txias thiab kub ua kom muaj zog thiab yooj;
3. Kev tsim kho kev ua tau zoo heev, tuaj yeem ua nplaum, thawb, xaws, qhwv, thiab lwm yam;
4. Kev tiv thaiv zoo tshaj plaws, ua rau cuam tshuam thiab ua lub pob;
5. Zoo heev kub rwb thaiv tsev kub, rwb thaiv tsev hluav taws xob thiab kev ua tau zoo sealing.
