Features Of Cnc Controller

1. Multi-coordinate and multi-system control, such as Fanuc's latest high-end controller 11s30i -model a system, the maximum number of control systems is 10 systems (channels), the maximum number of axes and the maximum number of spindle configurations is 40 axes, of which 32 feed axes Axes, the main axis is 8 axes, and the maximum number of simultaneous control axes is 24 axes/system. The maximum pmc system is 3 systems. The maximum number of i/o points is 4096 points/4096 points, and the basic command speed of pmc is 25ns. The largest pre-read block: 1000 blocks. This is currently the most equipped CNC system in the world. Due to the multi-axis and multi-system configuration, it is especially suitable for the needs of large-scale automatic machine tools, compound machine tools, and multi-head machine tools.

2. High-precision and high-speed machining function This is the most important function of the cnc system. Thanks to this function, the manufacturing technology (mt) has been greatly developed. The CNC machine tool adopts computer control, which can ensure that the processed parts have high precision and repeatability. But in order to obtain a certain function, the signal input to the controller has to undergo a series of processing, which inevitably requires distortion and delay. Therefore, in high-speed machining, certain measures must be taken to reduce distortion and delay to maintain high machining accuracy. High-precision, high-speed processing, in addition to mechanical design and manufacturing to ensure that the target can be achieved, the main requirements for the cnc system are fast processing speed and high control accuracy. The feedforward control is used to compensate the error caused by the servo lag and improve the machining accuracy. Properly controlling the feed rate and adopting the appropriate acceleration and deceleration curve can reduce the error caused by the acceleration and deceleration lag. "Foresight" control performs calculation, processing and multi-segment buffering of motion data before program execution, so as to control the tool to move at high speed, and the error is small. For the high-precision contour control of the smooth running of the machine tool, real-time recognition of the command form is adopted to optimally control the speed, acceleration and jerk, so that the processing is always kept in the best state. In order to prevent disturbances, a digital filter technology was developed to eliminate mechanical resonance and improve the position gain of the servo system. High precision feed and spindle servo system are very important for high speed, high precision and high efficiency. At present, its performance is mainly improved from the following aspects. Reduce the size of the motor, driver and control unit, and improve the resolution of the encoder; the linear movement axis can be driven by a linear servo motor; reduce the mechanical transmission chain, improve the rigidity, and improve the accuracy. When the spindle motor adopts a synchronous motor, it is very suitable for the system of a gear machine tool, which sometimes requires a very low spindle speed, but the accuracy is very high. For example, the fanuc servo motor has a small design and uses high gain control. The servo motor is a cogging-free motor with an encoder with a resolution of 1.6xlo' pulse/revolution. Servo control adopts AC digital servo control, which has high current detection accuracy. Using corresponding hardware, it can produce so-called "nano control", that is, when the system detection resolution is 1 ridge m, the interpolation resolution can reach 1nm; it Minimize the calculation error in the cnc, and use nanometers or smaller units for each internal calculation, which greatly improves the quality of processing. For the control of linear motors, a digital filter is designed to avoid the multi-point resonance characteristics caused by the direct drive mechanism. Combining these functions, the movement of the machine tool can be executed accurately according to instructions. For processing molds with free-form surfaces, stripes will appear between program segments. In order to solve this problem, fanuc has developed a "nano-smoothing" function, which rounds the tolerance of the cnc command, evaluates the original curve in units of "nano", and It performs nurbs interpolation. These properties meet the requirements of "high speed and high precision" and "low speed and high precision" of machine tools.

3. Shaft machining and complex machining functions. As the 5-axis machining process is reasonable, it can make full use of the best geometric shape of the tool for cutting, compared with 3D curved surface machining, which can improve efficiency and improve finish in high-speed and high-precision machining of complex shapes . Therefore, it is more and more widely used. The configuration of 5-axis machining machinery mainly includes tool rotation mode, table rotation mode and a combination of these two modes. Therefore, the 5-axis machining function must be able to meet the requirements of various configurations. According to the characteristics of 5-axis machining, they, such as tcp (tool center control), tool radius compensation and other functions, are applied to 5-axis machining machines with different mechanical configurations.

4. Numerical control complex function In order to improve productivity, the development and manufacture of numerical control compound processing machine tools has become a development trend of numerical control machine tools. The compound processing machine tool refers to the processing of multiple processes on the same machine, such as turning, milling, and hammering on a machine tool. For example, a cylinder needs to be turned on the cylindrical surface, hammered, etc. It is also required to mill grooves on the cylindrical surface, and these processing must be completed on the same CNC machine tool. This can greatly increase productivity. Therefore, for CNC compound machine tools, Baixian needs to add a control system that can be used to perform compound processing functions. For example, a milling machine needs to add a spiral cone line function, a spiral line function, a 3D arc function, a tool center point control, etc. In addition, the tool The compensation function also needs to have both turning and milling functions. In addition, this machine tool often requires high-speed machining. In order to centrally monitor and manage multiple machine tools through the PC or the CNC system itself, the system needs to communicate through the network. In order to transfer the program and monitor the processing status. In addition, the network function can also transmit maintenance data, remotely control, operate and diagnose the system; transmit cad/ cam data. Cnc has the function of on-site communication network, which can transfer control, monitoring and diagnostic data between cnc and servo device, and between cnc and i/o control. Currently, Ethernet and fieldbus are mainly used. With the development of technology, applied wireless technology has also appeared. Wireless technology can make information reach almost anywhere.

6. High reliability and safety function The cnc system works in the bottom workshop together with the CNC machine tool, and is subjected to harsh environments such as: temperature, humidity, vibration, oil mist, dust, and continuous operation; therefore, it is reliable In addition to measures such as reliability design and manufacturing technology, the reliability of modern CNC systems mainly adopts the following measures: ①Using optical fibers to reduce cable connections. For example, Fanuc's CNC system connects CNC and servo amplifiers through optical fibers. High-speed transmission of large amounts of data from cnc to multiple servo amplifiers. ② Use error correction code (ecc: enorcorrecting code) to transmit data. As the software processes a large amount of data at high speed, the processing speed of the microprocessor, memory and lsi is also required to be greatly improved. Because these high-speed electronic components mounted on the printed board of the cnc perform high-speed reading, writing and data transfer, the signal waveform driven by the ic becomes lagging. Under such conditions, when the analog circuit processing method is not used, it results in The digital signal cannot be transmitted correctly. In addition, when the latest electronic components are supplied with low voltage, the operating range of the circuit with low noise resistance is reduced. For this reason, the cnc circuit will adopt more advanced error correction codes to transmit data. ecc is a leading high-reliability technology. By adding ecc to data to transmit various types of data, the system is more reliable. ②Using dual check safety (dual check sa and cylinder y) measures. "Double inspection safety" is consistent with European safety standards (en954-1). Its principle is to embed multiple processors in the cnc to redundantly monitor servo motors and spindle motors, as well as safety-related i/ 0 signals, and use emergency stop and related i/ 0 circuits to make the system run and stop safely.