Precision machining is a process of changing the size or performance of a workpiece with machining machinery. According to the temperature state of the workpiece to be machined, it is divided into cold machining and hot machining. Machining at room temperature, which does not cause chemical or physical changes in the workpiece, is called cold machining. Processing at a temperature higher or lower than room temperature will cause chemical or physical changes in the workpiece and is called hot processing. Cold machining can be divided into cutting and pressure machining according to the difference of processing methods. Hot working commonly includes heat treatment, forging, casting and welding.
Precision machining surface treatment
1、On the machined surface of the parts, there should be no scratches, abrasions and other defects that damage the surface of the parts.
2、No defects such as black skin, bump, messy buckle and burr are allowed on the machined thread surface. Before painting, all steel parts must be free of rust, oxide, grease, dust, mud, salt and dirt.
3、Before removing rust, remove grease and dirt from the surface of steel parts with organic solvent, alkali, emulsifier, steam, etc.
4、The time interval between the surface to be coated by shot blasting or manual rust removal and the primer coating shall not be more than 6h.
5, riveted parts in contact with each other's surface, before connecting must be coated with a thickness of 30 ~ 40μm anti-rust paint. The edge of the lap joint should be closed with paint, putty or adhesive. The primer damaged due to processing or welding should be repainted.
