Sheet metal parts are the products manufactured by metal plate technology, produced by means of filament winding, laser cutting, heavy processing, metal bonding, metal drawing, plasma cutting, precision welding, roll forming, sheet metal brake forming, die forging, water-jet cutting. Characteristics of sheet metal are light weight, high strength, electric conduction (used for electromagnetic shielding), low cost and large-scale quantity production. Widely used in Electrical and Electronic Engineering, communication, automobile industry, medical apparatus and instruments, such as computer case, mobile phone, MP3, sheet metal is an essential part.