Servo system is an important part of CNC machine tools, used to achieve the CNC machine tool feed servo control and spindle servo control. The function of the servo system is to receive the instruction information from the numerical control device, after the power amplification, shaping processing, into the machine tool actuator linear displacement or angular displacement movement. Because the servo system is the last link of the NC machine tool, its performance will directly affect the accuracy and speed of the NC machine tool, and so on, it is required to have good quick reaction performance, to track the digital command signal sent out by the numerical control device accurately and sensitively, and to be able to execute the command from the numerical control device faithfully, the dynamic tracking characteristic and static tracking precision of the system are improved.

The servo system includes the driving device and the actuator. The driving device is composed of a spindle driving unit, a feed driving unit, a spindle servo motor and a feed servo motor. 

Stepper motor, DC servo motors and AC servo motors are common driving devices. The measuring element detects the actual displacement value of each coordinate axis of the NC machine tool and inputs it into the NC device of the machine tool through the feedback system. The NC device compares the actual displacement value returned by the feedback with the instruction value, and output to the servo system to achieve the set value of the required displacement instructions.

Main Body of machine tool main body of machine tool is numerical control machine tool.

 The machine comprises a bed body, a base, a column, a cross beam, a slide seat, a worktable, a spindle box, a feed mechanism, a tool holder, an automatic tool changing device and other mechanical parts. It is in the numerical control machine tool to automatically complete a variety of mechanical parts of the cutting process. Compared with traditional machine tools, the main body of NC machine tool has the following structural features: 

1) the new structure with high stiffness, high seismic resistance and small thermal deformation is adopted. In order to improve the rigidity and anti-seismic of the machine tool, the methods of increasing the static stiffness, increasing the damping, adjusting the quality and natural frequency of the structural parts are usually used. The influence of thermal deformation on the main machine can be reduced by improving the structure and layout of the machine tool, reducing heating, controlling temperature rise and adopting thermal displacement compensation.

 2) high performance spindle servo drive and feed servo drive are widely used to shorten the transmission chain of CNC machine tool and simplify the structure of mechanical transmission system. 

3) adopt high transmission efficiency, high precision, no gap transmission device and moving parts, such as ball screw nut pair, plastic slide guide, linear rolling guide, hydrostatic guide, etc. . The auxiliary device of NC machine tool is necessary to make full use of the function of NC machine tool. 

The common auxiliary devices include: pneumatic, hydraulic device, chip removal device, cooling, lubricating device, rotary table and NC dividing head, protection, lighting and other auxiliary devices.