For the processing of complex workpieces, circular feed motion with X, Y and Z axes is often required to complete the processing of such workpieces. The vertical machining center is usually completed by installing the fourth axis, of which the CNC rotary table is a typical device of this type. It can be realized by moving back and forth to feed the table. In addition to being used for various arc processing or curved surface processing in conjunction with linear feed, the CNC rotary table can also achieve accurate automatic indexing.