Milling is the most important machining process in the machining center. It can be said that all machining processes in the machining center are carried out through milling. Milling can be divided into reverse milling and forward milling according to the direction of spindle movement and workpiece feed. It is an efficient and common machining method for machining centers to cut workpieces with rotating multi-edge tools. Suitable for machining plane, groove, all kinds of complex surface and curved surface mold and other special surface.