With the continuous development of the world’s advanced manufacturing technology, the application of ultra-high-speed cutting, ultra-precision machining and other technologies, the rapid development of flexible manufacturing systems and the continuous maturity of computer integrated systems, have put forward higher requirements for CNC machining technology. Today’s CNC machine tool industry will develop towards the following six trends.
1. All kinds of machining centers equipped with automatic tool changer (tool magazine capacity can reach more than 100) can realize milling, boring, drilling, turning, reaming and reaming on the same machine , Tapping and other processes, modern CNC machine tools also use multi-spindle, polyhedron cutting, that is, cutting different parts of a part at the same time in different ways. The numerical control system adopts multi-CPU structure and hierarchical interrupt control mode, so that parts processing and programming can be performed on one machine tool at the same time, so as to realize the so-called “foreground processing, background editing”. In order to meet the requirements of flexible manufacturing systems and computer integrated systems, the CNC system has a long-distance serial interface, and can even be networked to realize data communication between CNC machine tools, and can also directly control multiple CNC machine tools.
2. High-speed, high-precision speed and precision are two important indicators of CNC machine tools, which directly relate to processing efficiency and product quality. At present, the numerical control system uses a processor with a higher number of digits and a higher frequency to increase the basic operation speed of the system. At the same time, the use of ultra-large-scale integrated circuits and multi-microprocessor structures to improve the system’s data processing capacity, that is, to improve the speed and accuracy of interpolation operations. And adopt linear motor to directly drive the linear servo feed mode of the machine tool table, its high speed and dynamic response characteristics are quite superior. The feedforward control technology is used to greatly reduce the tracking lag error, thereby improving the machining accuracy of corner cutting.
In order to meet the requirements of ultra-high-speed machining, the CNC machine tool adopts the structure form of combining the spindle motor and the machine tool spindle into one, and realizes the integration of the frequency conversion motor and the machine tool spindle. The bearing of the spindle motor adopts the magnetic bearing, the hydrostatic bearing or the ceramic rolling bearing, etc. form. At present, ceramic tools and diamond-coated tools have begun to be applied.
3. The intelligent modern CNC machine tool will introduce adaptive control technology to automatically adjust the working parameters according to the changes in cutting conditions, so that the best working state can be maintained during the processing process, thereby obtaining higher processing accuracy and smaller surface roughness , At the same time, it can also improve the service life of the tool and the production efficiency of the equipment. It has self-diagnosis and self-repair functions. In the whole working state, the system performs self-diagnosis and inspection on the CNC system itself and various devices connected to it at any time. Once a fault occurs, measures such as shutdown are immediately adopted, and a fault alarm is given to indicate the location and cause of the fault. It can also automatically take the faulty module offline and switch on the standby module to ensure the requirements of unmanned working environment. In order to achieve higher fault diagnosis requirements, its development trend is to use artificial intelligence expert diagnosis system.
4. CNC programming automation With the development of computer application technology, currently CAD/CAM graphics interactive automatic programming has been widely used, which is a new trend in the development of CNC technology. It is a part processing drawing drawn by CAD, and then calculated and post-processed by the tool trajectory data in the computer, thereby automatically generating NC part processing programs to realize the integration of CAD and CAM. With the development of CIMS technology, there is now a fully automatic CAD/CAPP/CAM integrated programming method. The biggest difference between it and CAD/CAM system programming is that the processing technology parameters required for programming do not need to be manually participated, directly from the system Obtained within the CAPP database.
5. Reliability maximization The reliability of CNC machine tools has always been the main indicator that users care about most. The numerical control system will use a higher integrated circuit chip, using large-scale or ultra-large-scale dedicated and hybrid integrated circuits to reduce the number of components to improve reliability. The hardware function is softwareized to meet the requirements of various control functions. At the same time, the modularization, standardization, generalization and serialization of the machine structure of the hardware structure are adopted, which not only improves the hardware production volume, but also facilitates the organization of production and quality control. It also automatically diagnoses and alarms the hardware, software, and various external devices in the system by automatically running various diagnostic programs such as startup diagnosis, online diagnosis, and offline diagnosis. Use alarm prompts to eliminate faults in a timely manner; use fault-tolerant technology to adopt “redundant” design for important components to achieve fault self-recovery; use various testing and monitoring technologies to produce various products such as overtravel, knife damage, interference, power outage, etc. When an accident occurs, the corresponding protection is automatically performed.
6. Miniaturization of control system The miniaturization of numerical control system facilitates the integration of machine and electrical devices. At present, ultra-large-scale integrated components and multi-layer printed circuit boards are mainly used, and the three-dimensional mounting method is used to enable high-density installation of electronic components and reduce the space occupied by the system on a larger scale. The use of a new type of color liquid crystal thin display to replace the traditional cathode ray tube will make the CNC operating system further miniaturized. In this way, it can be easily installed on the machine tool equipment, and it is more convenient for the operation and use of the CNC machine tool.