Machining centers are developed from CNC milling machines. The biggest difference with the CNC milling machine is that the machining center has the ability of automatic exchange machining, by installing tools for different purposes on the tool magazine, the machining tools on the spindle can be changed by the automatic tool changer in a single clamping to realize a variety of machining functions. CNC machining centers are high-efficiency automated machine tools suitable for machining complex parts, which are composed of mechanical equipment and CNC systems. Its comprehensive processing capability is stronger, the workpiece can be completed after a clamping more processing content, processing accuracy is higher, on the medium processing difficulty of the batch of workpieces, the efficiency of ordinary equipment is 5 to 10 times, especially it can complete many ordinary equipment can not be completed machining, the shape of the more complex, high precision requirements of the single piece of machining or small and medium batches of multi-species production is more suitable. It concentrates the functions of milling, boring, drilling, thread tapping and thread cutting in one equipment, which makes it have a variety of machining process technology means.