What is sheet metal processing? Sheet metal processing (or CNC sheet metal processing) is defined as the mechanical or thermal processing of sheets. Sheet consists of boards of metal which were produced by a rolling process. It is divided into thin sheets, up to 3 mm, and heavy plates with a thickness of more than 3 mm. Most metals can be processed into sheets and further treated afterwards. Most frequently processed materials are: aluminum, structural steel, copper and stainless steel. For the initial processing of these sheets usually one of the following methods is selected: e.g. laser cutting, nibbling, stamping and bending, precision cutting, shearing. These manufacturing processes are all CNC-controlled on the basis of CAD/CAM-designed data. Downstream processes mainly include deep-drawing, bending, plate rolling, plate straightening, clinching, laser cutting 3D, fineblanking, spinning, pressing and punching, stamping / bending.