The development trend of modern CNC machine tools is high speed, high precision, high reliability, multi-function, compound, intelligent and open structure. The main development trend is the development of intelligent full-function general-purpose numerical control devices with open architecture in both software and hardware. NC technology is the foundation of machining automation and the core technology of NC machine tools. Its level is related to the country's strategic position and the level of reflecting the country's comprehensive strength. With the development of information technology, microelectronics technology, automation technology and testing technology, development of. NC machining center is a NC machine tool with a tool magazine and automatic tool change. The features of machining parts on the machining center are: after the machined parts are clamped once, the CNC system can control the machine tool to automatically select and change tools according to different procedures; automatically change the machine tool spindle speed, feed amount and tool's relative trajectory Other auxiliary functions, such as drilling, countersinking, reaming, boring, tapping, milling, etc., are automatically performed on each working surface of the workpiece continuously. Because the machining center can complete a variety of procedures centrally and automatically, it avoids human operating errors, reduces workpiece clamping, measurement and machine tool adjustment time, and workpiece turnover, handling and storage time, which greatly improves processing efficiency and processing accuracy. , So it has good economic benefits. The machining center can be divided into vertical machining center and horizontal machining center according to the position of the spindle in space.