It is a processing method of automobile maintenance, also called cold working. To put it bluntly, if the appearance of the car body is damaged and deformed, the sheet metal process is needed to restore the original appearance. Basically, the tool used is a hammer. With hammers of different shapes, the iron block is placed behind the sheet metal part and hammered repeatedly to shape it. If necessary, use the Appearance Restorer. This thing actually belongs to welding. Weld the iron ring on the car body and pull it out with the hook. Used to repair the sunken part. The large flat body is usually difficult to put back in place, so it is sometimes used to turn off the fire. That is, local heating and cooling make the iron sheet shrink. The ultimate goal is to restore the damaged body to its original appearance. 2. Sheet metal: Sheet metal means a series of processes for thin sheet metal, including folding, cutting, punching, welding, riveting and splicing. 3. This is a design module, mainly for things made of sheet metal materials. It is different from the entity, the thickness of the entity has changed, but the sheet metal is basically the same thickness, and many of them are sheet metal in life. The concept of automobile collision repair In the traditional sense, automobile collision repair is simply to fix the damaged and deformed automobile body after collision, then repair it by heating and mechanical stretching, then adjust and repair the gaps and shapes of the steel plate, door and pillar of the automobile body with simple tools such as hammer, and finally restore the original appearance with putty, putty and repair paint. However, with the in-depth development of automobile industry, many advanced materials are applied to automobile production, which makes many parts on the automobile body play a role in safety protection for drivers and passengers. Automobile collision repair has developed from the original "smashing welding repair" to "secondary manufacturing and assembly of automobile body", and the repaired automobile body should be restored to the factory state. Vehicle repair in a collision accident is no longer a simple automotive sheet metal knock! The quality of repair can not be observed by naked eyes alone. To repair a vehicle damaged by collision, the maintenance personnel should not only know the technical parameters and overall dimensions of the vehicle body, but also master the material characteristics, stress characteristics, force transmission, deformation trend and stress points of the vehicle body and the production technology of the vehicle body, such as welding technology. On the basis of mastering these knowledge, maintenance personnel should also use advanced measuring tools and accurate three-dimensional measurement of the car body to judge the direct and indirect damage and deformation of the car body and the hidden dangers caused by the car body deformation, formulate a complete car body repair plan, and then cooperate with correct maintenance technology and accurate three-dimensional data of car body key points to restore the car body key points to their original positions and restore the damaged car body to the factory state.