The method of machining the surface of cnc machining parts depends on the technical requirements of the machining surface. However, it should be noted that these technical requirements are not necessarily the requirements stipulated in the parts drawing, and may sometimes be higher than the requirements in the part drawing due to technical reasons. For example, due to the non-coincidence of the benchmarks, the processing requirements on the surface of some CNC machining parts are increased. Or because it is used as a precision benchmark, it may put forward higher processing requirements. When the technical requirements of the surface of each cnc processed part are clarified, the final processing method that can guarantee this requirement can be selected accordingly, and the processing steps required for several steps and each step are determined. The selected cnc processing method should meet the requirements of the quality of parts, good processing economy and high production efficiency. For this reason, the following factors should be considered when choosing a processing method: 1. The processing accuracy and surface roughness that can be obtained with any cnc processing method have a considerable range, but only in a narrower range is economical Yes, the processing accuracy in this range is the economical processing accuracy. For this reason, when selecting a processing method, the corresponding processing method that can obtain economical processing accuracy should be selected. 2. It is necessary to consider the nature of cnc processed parts materials. 3. To consider the structural shape and size of cnc processed parts. 4. To consider productivity and economic requirements. When mass production is in mass, advanced and efficient processes should be used. It can even fundamentally change the manufacturing method of the blank, which can reduce the labor of mechanical processing. 5. It is necessary to consider the existing equipment and technical conditions of the factory or workshop. When selecting the processing method, the existing equipment should be fully utilized to tap the potential of the enterprise and give play to the enthusiasm and creativity of the workers. But we should also consider continuously improving the existing processing methods and equipment, adopting new technologies and improving the level of technology.