In the late 1940s, the United States began to study CNC milling machine, in 1952, the Massachusetts Institute of Technology (mit) servo mechanism laboratory successfully developed the first CNC milling machine, and put into use in 1957. This is a major breakthrough in the development of manufacturing technology, marking the beginning of the era of NC machining in the manufacturing field. NC machining is the foundation of modern manufacturing technology. This invention has epoch-making significance and far-reaching impact on the manufacturing industry. The major developed countries in the world attach great importance to the research and development of NC machining technology. China began to develop CNC milling machine in 1958, successfully trial-produced CNC milling machine with sub-tube CNC system, 1965 began to mass-produce three-coordinate CNC milling machine with transistor CNC system. After decades of development, the current CNC milling machine has realized computer control and has been widely used in industry, especially in the mold manufacturing industry.

According to the requirements of metal cutting processes such as turning, milling, grinding, drilling and planer, and special machining processes such as electrical machining and laser machining, various kinds of NC milling machines are developed. There are many kinds of CNC milling machines. Generally, CNC milling machines can be divided into 16 categories:

1 CNC lathe (turning center with milling function)

2 CNC milling machine (including milling center)

3 CNC clam bed

4 machining center based on milling process.

5 CNC grinding machine (including grinding center)

6 CNC drilling machine (including drilling center)

7 CNC broaching machine

8 NC planer

9 CNC cutting milling machine

10 CNC gear milling machine

11 CNC laser milling machine

12 CNC WEDM milling machine

13 CNC EDM milling machine (including electrical machining center)

14 CNC board Village shaping milling machine

15 CNC tube forming milling machine

16 other CNC milling machines

CNC milling machines commonly used in mold manufacturing are: CNC milling machine, CNC EDM forming milling machine, CNC WEDM milling machine, CNC grinding machine and CNC lathe.

CNC milling machine is usually composed of control system, servo system, detection system, mechanical transmission system and other auxiliary systems.

The control system is used for the operation, management and control of the NC milling machine. The data are obtained through the input medium, and the data are interpreted and calculated. The servo system drives the milling machine according to the instructions of the control system, so that the cutter and parts execute the movement specified by the NC code. The detection system is used to detect the milling. The displacement and velocity variation of the machine actuator (worktable, turntable, sliding plate, etc.) are fed back to the input and compared with the input instructions to adjust the milling machine motion according to their differences. Various, such as: fixed cycle (can carry out a variety of repeated processing), automatic tool change (can be exchanged specified tool), transmission clearance compensation mechanical transmission system caused by clearance error, and so on.

In NC machining, NC milling is the most complicated and many problems need to be solved. Besides NC milling, NC WEDM, NC EDM, NC turning, NC grinding and other NC programming have their own characteristics.

The function of servo system is to transform the pulse signal from the numerical control device into the movement of the moving parts of the milling machine.