Sheet metal is the process of stamping some sheet metal by hand or in a die to produce plastic deformation, forming the desired shape and size, and further by welding or a small amount of mechanical processing to form more complex parts, usually, the four most important steps in sheet metal processing are shearing, punching/cutting, folding/winding, welding, surface treatment, etc. . With the more and more extensive application of sheet metal, the design of sheet metal parts has become a product, which is an important link in the development process. Sheet metal has the characteristics of light weight, high strength, conductive (can be used for electromagnetic shielding) , low cost, good mass production performance, etc. , for example, in computer case, mobile phone, MP3, sheet metal is an essential component.