As enterprises put forward higher requirements for machining accuracy and productivity, the principle of process concentration is being adopted, and various types of machining center machine tools have emerged. The machining center not only has all the functions of general CNC machine tools, but also has tool magazine and automatic tool change device, breaking the traditional concept that only oneortwo processes can be completed on a CNC machine tool. Taking the milling machining center as an example, a large capacity tool magazine (generally able to accommodate 20-120 various tools) and an automatic tool pressing device are added to the CNC milling machine. After the workpiece is clamped at one time, most of the machined surfaces of the parts can be processed by multiple processes such as milling, boring, drilling, reaming, dumpling hole and tapping. In recent years, the pentahedral machining center machine tool can complete the machining of all surfaces of the box type except the mounting surface in one clamping. Turning machining center has also been widely used. It can complete all machining processes of rotating parts (including turning internal and external surfaces, milling planes, milling grooves, drilling and tapping, etc.) in one clamping. The machining center machine tool can effectively avoid the positioning error caused by multiple clamping, and reduce the number and floor area of the machine tool, which greatly improves the productivity and processing automation. The method of classification according to process use can play an important guiding role in the continuous development of new products of CNC machine tools.
