For NC machining of plane section method, the machining path of tool cutting plane and implicit surface can be found, and the curve of the tool path is drawn by the positive-negative method.

Using this method, the post-machining inner surface is obtained, and it makes the cutting locus planning in NC machining process possible.

The principle of the vibration cutting is discussed. It is pointed out that the vibration cutting is an important method to improve the machined surface integrity of components.