Precision machining is a process in which the dimensions or properties of a workpiece are changed with a processing machine. According to the temperature state of the workpiece to be processed, it is divided into cold processing and hot processing. Generally processed at room temperature, and does not cause chemical or phase changes in the workpiece, called cold processing.

Generally, processing at a state higher than or lower than normal temperature will cause chemical or phase changes in the workpiece, called hot processing. Cold processing can be divided into cutting processing and pressure processing according to the difference in processing methods. Common hot work is heat treatment, forging, casting and welding. Fine machining, broadly speaking, refers to the processing of small sizes or small operating sizes.

The general outline size is less than 3 mm, and the processing technology with little or no cutting is a fine processing. It is widely used in aerospace, precision instruments, biomedicine and so on. In addition to mechanical processing, fine processing mostly uses electrical processing, chemical processing, wave processing, plasma, laser, particle, lithography and other technological means.

From a narrow point of view, fine machining mainly refers to semiconductor integrated circuit manufacturing technology. Fine machining, not necessarily precision machining. Especially in the field of semiconductor integrated circuit manufacturing technology, their definition and requirements for precision are different from the definition of precision in traditional machining. CNC machine tools are not necessarily precision machines. Numerical control technology is to solve the control, detection, feedback, calculation and part of the executive mechanism. The accuracy of machining mainly depends on the accuracy of mechanical components.