Precision machining is the process of changing the size or performance of a workpiece with a processing machine. According to the temperature state of the workpiece being processed, it is divided into cold working and hot working. Generally processed at room temperature, and does not cause chemical or physical phase changes of the workpiece, called cold processing. Generally, processing at a temperature higher or lower than the normal temperature causes a chemical or physical phase change of the workpiece, which is called thermal processing. Cold machining can be divided into machining and pressure machining according to the difference in processing methods. Thermal processing is commonly used for heat treatment, forging, casting and welding
Generally, machining is divided into three stages: general machining, precision machining, and ultra-precision machining. At present, precision machining refers to processing technology with a processing accuracy of 1 to 0.1 μm and a surface roughness of Ra 0.1 to 0.01 μm. However, this limit is constantly changing with the advancement of processing technology. Today's precision machining may be tomorrow's. General processing.
The problems to be solved by precision machining are: machining accuracy, including geometrical tolerance, dimensional accuracy and surface condition; second, processing efficiency, some machining can achieve better machining accuracy, but it is difficult to achieve high machining efficiency.