The so-called assembly is to set up a number of parts or components together in a certain way to make it a complete material. It is necessary to pay attention to the protection of the material, not scratch. Assembly is the last step of a finished product. If the material is not able to be used for bruising, it needs to be redone and redone, which will waste a lot of processing hours and increase the cost of material. Therefore, we should pay special attention to the protection of the material.