See Servo Control on CNC Machine Tools

As a machine tool, especially the important functional components of CNC machine tools, the servo system is an important indicator that affects the processing performance of the system. Through the understanding of the servo system application in the machine tool industry to continuously improve its application in the machine tool industry.

Horizontal CNC machine tools consist of CNC controllers, servo drives, and motors, electrical cabinets, and racks of CNC machine tools. Its working principle is: through the special programming software configured in the CNC, the trajectory of the machined parts is expressed in the form of coordinates, and these information are converted into signals (pulse trains) that can drive the servo motor with power, and the servo is controlled. The motor drives the corresponding axis to achieve the trajectory. At the same time, the cutter holder is equipped with a numerically controlled lathe, and the corresponding workpiece is processed by cutting the machining material fixed on the spindle by configuring the corresponding cutter according to the machining material.

In CNC machine tools, servo control system is an indispensable part. Its task is to translate the numerical control information into the machine feed motion to achieve precise control. Since CNC machine tools require high product processing, the servo control system used is critical.

The advantages of the servo control system currently used on CNC machine tools are: high accuracy, and the accuracy of the servo system refers to the precision of the output quantity to reproduce the input quantity. Including positioning accuracy and contour machining accuracy; stability is good, stability refers to the system under a given input or outside interference, after a brief adjustment process, to reach a new or restored to the original equilibrium state. Directly affect the accuracy and surface roughness of CNC machining; rapid response, rapid response is an important indicator of the dynamic quality of the servo system, it reflects the tracking accuracy of the system; wide speed range, its speed range up to 0-30m/min; The servo control of low speed and large torque and feed coordinate belongs to constant torque control. This torque should be maintained throughout the entire speed range. Servo control of spindle coordinate is constant torque control at low speed, which can provide large torque. Constant power control at high speed, with sufficient output power.

In the feed servo of the machine tool, the permanent magnet synchronous AC servo system is mainly used. There are three types: analog form, digital form, and software form. The analog servo is single-purpose and only receives analog signals. The position control is usually implemented by the upper computer. Digital servos can be used for multiple purposes such as speed, torque and position control. Can receive analog commands and pulse commands, all kinds of parameters are set by digital, good stability. Has a rich self-diagnosis, alarm function. Software servo is a microprocessor-based all-digital servo system. It implements various control methods and monitoring programs for servo motors of different specifications and power in software. When used, the user can set the code and related data to automatically enter the working state. With digital interface, changing the working method, changing the motor specifications, just reset the code, it is also called universal servo.

AC servo has occupied the dominant position of the machine feed servo, and continues to improve with the development of new technologies, embodied in three aspects. First, the power electronic devices in the system power drive device continue to develop in the direction of high frequency, the intelligent power module is popularized and applied, and the second is based on the maturity of microprocessor embedded platform technology, which will promote the application of advanced control algorithms; It is the promotion of the networked manufacturing model and the maturity of fieldbus technology that will enable network-based servo control.

Currently in the machine tool industry, many domestic and foreign manufacturers have servo products in the industry, among which Siemens, Bosch Rexroth, domestic Dongneng, Huichuan, Delta and other products have performed well in 2011.