The process design of CNC machining is very specific. When using general-purpose machine tools, many specific process problems, such as the division and arrangement of steps in the process, the geometry of the tool, the path of the cutting tool and the amount of cutting, etc., to a large extent They are all considered and decided by the operating workers based on their own practical experience and habits. Generally, there is no need for the craftsman to make excessive regulations when designing the process rules. In the processing of numerically-controlled machine tools, the above-mentioned specific technological problems not only become the contents that must be considered when designing the numerical control process, but also must make correct choices and be incorporated into the processing program.