If the machining part is a curved contour, the system that selects the two-coordinate linkage and the three-coordinate linkage should be determined according to the geometry of the surface. According to the requirements of parts processing, on the basis of the general CNC milling machine, the numerical control indexing head or the numerical control rotary table can be added. At this time, the system of the machine tool is a four-coordinate numerical control system, which can process spiral grooves, blade parts, etc. Tag：cnc milling service/ cnc precision milling/ high speed milling/ mill parts/ milling/ precision milling