CNC milling machines generally do not need to use special process equipment such as special fixtures. When replacing workpieces, they only need to call the processing program, clamping tools and adjusting tool data stored in the CNC device, which greatly shortens the production cycle. Secondly, the CNC milling machine has the functions of milling machine, boring machine and drilling machine, Vertical machining center which makes the process highly concentrated and greatly improves the production efficiency. In addition, the spindle speed and feed speed of NC milling machine are stepless, so it is conducive to select the best cutting parameters;