In layman's terms, sheet metal is a tinsmith, and automobile sheet metal workers are a type of technical work that specializes in repairing the shape of automobile shells. In the past, all car shells were hammered out by sheet metal workers. Sheet metal workers are actually the same, but there are differences in technology. The same materials, the same defects, and the work results of different technical levels are different. The higher the level, the better it can be restored to its original state, so less putty powder will be used for repairs. The repaired areas with less putty powder will not be prone to crusting and cracking (which will happen when exposed to cold or heat).