Numerical control technology is a digital program to control the realization of automatic mechanical CNC technology. It is widely used in the field of mechanical manufacturing and automation, to bette...
Numerical control technology is a digital program to control the realization of automatic mechanical CNC technology. It is widely used in the field of mechanical manufacturing and automation, to better solve the multi-species, small batch and complex parts processing and automation of the production process. With the rapid development of computer and automatic control technology, numerical control technology has been widely used in CNC machine tools, robots and various mechatronic devices. At the same time, the rapid social and economic development of the numerical control devices and numerical control machinery requirements in the theory and application of rapid development and improvement.
Servo system is an important part of CNC machine tools, numerical control machine tool accuracy and speed indicators are often determined by the servo system. With the development of technology, high-precision, high-performance AC servo has become a new trend of servo system development.
Second, an overview
CNC lathe, also known as CNC lathe, namely CNC lathe, is currently the largest and most widely used CNC machine tool in China. Generally it consists of input and output devices, CNC devices, servo system, detection feedback device and machine tool mainframe composition. It is one of the main varieties of CNC machine tools. It solves the problem of automatic machining of most mechanical parts and becomes the most important machining equipment. It occupies a very important place in CNC machine tools and has been valued by all countries in the world for decades The rapid development.
CNC machine tool servo drive system with or without feedback detection unit is divided into two types of closed-loop and open-loop, the two types of servo drive system is not exactly the same basic composition. But no matter what type, the implementation of components and their drive control unit are essential. The function of the drive control unit is to convert the feed command into the signal form required to drive the actuator, and the actuator converts the signal to the corresponding mechanical displacement. For closed-loop servo drive system, it is composed of the actuator, the drive control unit, the comparison control loop, the feedback detection unit, and machine tools. The feedback detection unit feedbacks the actual position of the workbench to the comparative control link, and compares the command signal with the feedback signal in comparison with the control link so as to follow the error of the servo system to the drive control unit, drive and control Components drive table movement. In the CNC system, due to the introduction of the computer, the function of the comparative control is completed by the software, resulting in some changes of the system structure, but basically it is composed of the actuator, the feedback detection unit, the comparison control section, the drive control unit and the machine tool.
Third, CNC industry outlook
With the development of the times, efficiency has become the most fundamental factor of efficiency. We are in a period of rapid development of manufacturing technology. The machining accuracy of CNC system directly affects the overall processing time.
The position accuracy of the servo system on CNC machine tools to a large extent determines the machining accuracy of CNC machine tools. Therefore, position accuracy is a very important indicator. CNC machine tool servo system in order to ensure adequate position accuracy, on the one hand is the correct choice of open-loop system magnification size, on the other hand is the accuracy of the position detection element requirements. Because in the closed-loop control system, the servo system of CNC machine tool is very difficult to distinguish the error of the detection component and the deviation of the detected quantity. The accuracy of the feedback detection component often plays a decisive role in the accuracy of the system. It can be said that the machining accuracy of CNC machine tools is mainly determined by the accuracy of the inspection system.
Displacement detection system can measure the minimum amount of displacement called resolution. The resolution depends not only on the test element itself, but also on the resolution or pulse equivalent of the measurement system, which generally requires an order of magnitude more precision than machining.
The reliability of a CNC machine tool servo system is one of the main quantitative indicators to evaluate the reliability. It is defined as the probability that a product fulfills its prescribed function under specified conditions and within a prescribed time. For CNC machine tools, its conditions refer to its environmental conditions, working conditions and working methods, such as temperature, humidity, vibration, power, interference intensity and operating procedures. Here mainly refers to the functions of CNC machine tools to use features such as CNC machine tools of various functions, servo performance. Average failure (failure) interval (MTBF) refers to the repair or replacement of parts can continue to work with repairable equipment or systems, CNC machine tool servo system from failure to the average time of the next failure, it is commonly used in CNC machine tools As a quantitative indicator of reliability.
CNC machine tool servo system as a result of numerical control devices using a microcomputer, the reliability greatly improved, so the reliability of the servo system is relatively prominent. Its main fault from the servo components and mechanical transmission parts. Hydraulic servo system is usually less reliable than the electrical servo system, solenoid valves, relays and other electromagnetic components of the reliability of poor, should try to use non-contact element instead. At present, CNC machine tools due to component quality, process conditions and cost constraints, its reliability is not high.
Fourth, the new Sichuan Electric servo system advantages
1. High-resolution servo can effectively meet the numerical control system for high-precision requirements.
2 servo response wide range of frequencies, can effectively adapt to the numerical control system load changes and rapid response requirements.
3. Servo provides a wealth of parameter settings, by setting the electronic gear ratio, frequency factor, S-curve, gain filtering parameters can be effectively with the host computer system to complete processing.
4. Servo low-speed high-precision steady-state, speed range, can adapt to some special industries on the speed requirements.
5. Servo reliability, you can use a variety of harsh environments, effectively improve system stability and anti-interference ability.
Five, concluding remarks
The use of the new Sichuan AC servo CNC lathe can achieve the performance of CNC machine tools to design, feed axis with quick start and stop, smooth operation, improve cutting accuracy and efficiency of good features.