In the late 1940s, the United States began to study CNC machine tools. In 1952, the first servo-controlled CNC milling machine was successfully developed by the MIT servo laboratory in the United States and was put into operation in 1957. This is a major breakthrough in the development of manufacturing technology, marking the beginning of the era of CNC machining in manufacturing. CNC machining is the foundation of modern manufacturing technology, an invention of epoch-making significance and far-reaching implications for the manufacturing industry. The world's major industrialized countries attach great importance to CNC machining technology research and development. China began to develop numerical control machine tools in 1958, successfully trial-produced CNC machine tools with sub-tube numerical control system, 1965 began mass production with transistor CNC system of three-coordinate CNC milling machine. After decades of development, the current CNC machine tools have achieved computer control and are widely used in industry, especially in the mold manufacturing industry. For the turning, milling, grinding, drilling and shaving and other metal cutting and processing and electrical processing, laser processing and other special processing needs, has developed a wide range of CNC machining machine tools. There are a wide range of CNC machine tools, CNC machine tools are generally divided into 16 categories: 1 CNC lathes (turning center with milling function) 2 CNC milling machine (including milling center) 3 CNC milling machine 4 to milling-based machining center. 5 CNC grinding machine (including grinding center) 6 CNC drilling machine (including drilling center) 7 CNC broaching machine 8 CNC planer 9 CNC cutting machine 10 CNC gear machining machine 11 CNC laser machining machine 12 CNC WEDM 13 CNC EDM Molding machine (including electric machining center) 14 NC Bancun forming machine tools 15 CNC tube forming machine tools 16 Other CNC machine tool manufacturing CNC machining commonly used machine tools are: CNC milling machine, CNC EDM machine tools, CNC WEDM , CNC grinding machines and CNC lathes. CNC machine tools usually by the control system, servo systems, testing systems, mechanical transmission systems and other auxiliary systems. The control system is used for the operation, management and control of CNC machine tools. The data are obtained through the input medium, which can be interpreted and calculated for these data and have an effect on the machine tool. The servo system drives the machine tool according to the instructions of the control system to make the tools and parts execute the NC codes The detection system is used to detect the displacement and speed variation of the execution parts (worktable, turntable, skateboard, etc.) of the machine tool, and the test results are fed back to the input end, compared with the input command, and the machine motion is adjusted according to the difference ; Machine tool drive system is fed by the servo drive components to the implementation of the machine tool between the mechanical transmission drive; A wide range of auxiliary systems, such as: canned cycle (a variety of repeated processing), automatic tool change Designated tool), transmission clearance compensation compensation for mechanical transmission system gap error) and so on. In NC machining, CNC milling is the most complex, and most problems to be solved. In addition to CNC milling outside the CNC wire cutting, CNC EDM, CNC turning, CNC grinding and other NC programming has its own characteristics, the book will focus on the introduction of numerical control machining programs with guidance CNC milling CNC Programming. Servo system is the role of the pulse from the CNC device into a machine tool moving parts.