Explore the development trend of CNC machine tool industry

With the rapid increase in the demand for CNC machine tools and the rapid advancement of computer technology and modern design technology in the manufacturing industry, the application of CNC machine tools continues to expand and continues to evolve to meet the needs of production and processing.

1, high speed

With the rapid development of industries such as automobiles, defense, aerospace, and aerospace, as well as the application of new materials such as aluminum alloys, the requirements for high-speed machining of CNC machine tools are increasing.

(1) Spindle speed: The machine adopts electric spindle (built-in spindle motor), and the maximum spindle speed reaches 200000r/min;

(2) Feed rate: When the resolution is 0.01μm, the maximum feed rate reaches 240m/min and the precise processing of complex surfaces can be obtained;

(3) Speed ​​of operation: The rapid development of microprocessors has provided a guarantee for the development of high-speed and high-precision CNC systems. The CPU has been developed to 32-bit and 64-bit numerical control systems. The frequency has been increased to several hundred megahertz and thousands. megahertz. Due to the greatly increased speed of operation, a feed rate of up to 24 to 240 m/min can still be achieved at resolutions of 0.1 μm and 0.01 μm.

(4) Tool change speed: At present, the tool exchange time of foreign advanced machining centers has generally been around 1s, and the height has reached 0.5s. The Chiron company in Germany designed the tool magazine as a basket style, with the spindle as the axis, and the tool was arranged on the circumference. The knife-to-knife tool change time was only 0.9s.

2, high precision
The precision requirements of numerically-controlled machine tools are now not limited to static geometrical accuracy. More attention has been paid to machine tool movement accuracy, thermal deformation, and vibration monitoring and compensation.

(1) Improve CNC system control accuracy: Adopt high-speed interpolation technology to achieve continuous feed with small program segments, refine the CNC control unit, and adopt high-resolution position detection device to improve position detection accuracy (Japan has developed The AC servo motor with built-in position detector of 106 pulses / rev, the position detection accuracy can reach 0.01μm / pulse), the position servo system adopts feedforward control and nonlinear control;

(2) Error compensation techniques: Backlash compensation, screw pitch error compensation and tool error compensation techniques are used to comprehensively compensate for thermal distortion and spatial errors of the equipment. The research results show that the application of comprehensive error compensation technology can reduce the machining error by 60% to 80%;

(3) Using a grid decoder to check and improve the precision of the movement trajectory of the machining center, and predict the machining accuracy of the machine tool through simulation, so as to ensure the positioning precision and repeat positioning accuracy of the machine tool, so that its performance is stable over a long period of time and can be under different operating conditions. Complete a variety of processing tasks and ensure the quality of parts.

3, function complex
The meaning of a compound machine tool refers to the realization of a single machine tool or the completion of the processing of various elements from the blank to the finished product. According to its structural characteristics, it can be divided into two types: process complex type and process complex type. Process compound machine tools such as boring and milling and drilling compounding - machining center, turning and milling compounding - turning center, milling and drilling boring machine compounding - compound machining center, etc.; process compound type machine tool such as multi-faceted and multi-axis machining compound machine tool and double spindle Turning center and so on. The use of a compound machine tool to process, reduce the workpiece loading and unloading, replacement and adjustment of the tool's auxiliary time and the error generated in the middle process, improve the part processing accuracy, shorten the product manufacturing cycle, improve the production efficiency and the manufacturer's market reaction ability, Compared with the traditional process of decentralized production methods have obvious advantages.

The compounding of the machining process has also led to the development of machine tools that are modular and multi-axis. The latest turning machining center of Index Company in Germany is a modular structure. The machining center can complete various operations such as turning, milling, drilling, hobbing, grinding, and laser heat treatment, and can complete all processing of complex parts. With the continuous improvement of modern machining requirements, a large number of multi-axis linkage CNC machine tools are increasingly welcomed by major companies.

4, control intelligence

With the development of artificial intelligence technology, in order to meet the development needs of flexible manufacturing and manufacturing automation in the manufacturing industry, the degree of intelligence in CNC machine tools is constantly increasing. Specifically embodied in the following aspects:

(1) Self-adaptive control of the machining process: By monitoring the cutting force in the machining process, the power of the spindle and the feed motor, current, voltage, etc., the identification is performed using traditional or modern algorithms to identify the tool's acceptance. Force, wear, damage status and stability of machine tool processing, and adjust the machining parameters (spindle speed, feedrate) and machining instructions in real time according to these conditions, so that the equipment is in the best operating state to improve the machining accuracy and reduce the machining surface. Roughness and improve the safety of equipment operation;

(2) Intelligent optimization and selection of processing parameters: Using the experience of process experts or technicians, the general and special laws of parts processing, and the use of modern intelligent methods to construct "intelligent optimization and selector of processing parameters" based on expert systems or models. , Use it to obtain optimized processing parameters, so as to achieve the purpose of improving programming efficiency, processing technology level, and shortening production preparation time;

(3) Intelligent fault self-diagnosis and self-healing technology: According to the existing fault information, the application of modern intelligent methods to achieve fast and accurate fault location;

(4) Intelligent fault playback and fault simulation technology: It can completely record various information of the system, play back and simulate various errors and accidents of CNC machine tools, determine the causes of errors, and find solutions to problems. Accumulation of production experience;

(5) Intelligent AC servo drive device: An intelligent servo system that can automatically identify the load and automatically adjust parameters, including intelligent spindle AC drive device and intelligent feed servo device. This kind of drive device can automatically identify the moment of inertia of the motor and the load, and automatically optimize and adjust the control system parameters so that the drive system can get the best operation.

(6) Intelligent 4M numerical control system: In the manufacturing process, integration of processing and inspection is an effective way to achieve rapid manufacturing, rapid detection, and rapid response. Measurement, modeling, machining, and machinery Manipulators (4Ms) are integrated into one system to share information and facilitate the integration of measurement, modeling, processing, fixtures, and operations.

5. System openness

(1) Open to future technologies: Since both software and hardware interfaces follow accepted standard protocols, only a few redesigns and adjustments are required. A new generation of general-purpose hardware and software resources may be adopted, absorbed, and compatible with existing systems. This means that the development cost of the system will be greatly reduced and the system performance and reliability will continue to improve and be in a long life cycle;

(2) Open to users' special requirements: update products, expand functions, provide various combinations of hardware and software products to meet special application requirements;

(3) The establishment of numerical control standards: Internationally, a new CNC system standard ISO14649 (STEP-NC) is being researched and developed to provide a neutral mechanism that does not depend on specific systems and can describe the entire life cycle of products. Unified data model to achieve standardization of product information throughout the entire manufacturing process and even in various industrial fields. The standardized programming language not only facilitates the use of the user, but also reduces the labor consumption directly related to the operating efficiency.

6, drive parallel connection

Parallel kinematic machine tool overcomes the inherent defects such as large mass of moving parts, low rigidity of the system, the fact that the tool can only feed along the fixed guide rail, low degree of freedom of operation, insufficient flexibility and flexibility of the equipment processing, and the like in the machine tool spindle (generally For the moving platform) and the base (usually the static platform) using a multi-bar parallel connection mechanism to drive, through the length of the rod in the control rod to make the platform supported by the rod to obtain the corresponding degree of freedom of movement, can achieve multi-coordinate linkage Processing, assembly and measurement of multiple functions can better meet the processing of complex special parts, with the advantages of modern robots with high degree of modularity, light weight and speed.

As a new type of processing equipment, the parallel machine tool has become an important research direction of current machine tool technology and has been highly valued by the international machine tool industry. It is considered to be “the most significant progress in the machine tool industry since the invention of CNC technology” and "A new generation of CNC machining equipment in the 21st century."

7. Extreme (larger and smaller)

Large-scale development of defense, aerospace, and aerospace businesses, and basic industries such as energy, require the support of large-scale and well-performing CNC machine tools. The ultra-precision machining technology and micro-nano technology are strategic technologies in the 21st century. New manufacturing processes and equipment that can adapt to the micro size and micro/nano processing precision need to be developed. Micro-machine tools include micro-cutting (car, milling, grinding) machines. Demand for microelectronics processing machines, micro-laser processing machines and micro-presses is gradually increasing.

8, <br> <br> information exchange network for businesses facing fierce competition, the CNC machine has a two-way, high-speed network communications capabilities to ensure the flow of information between various departments unimpeded workshop is very important. It can not only realize the sharing of network resources, but also realize the remote monitoring, control, training, teaching and management of CNC machine tools. It can also realize the digital service of CNC equipment (remote diagnosis and maintenance of CNC machine tool faults). For example, Mazak of Japan introduced a new generation of machining centers equipped with an external device called an e-Tower, including computers, mobile phones, off-camera and in-camera cameras, capable of voice, graphics, video, and text The functions of communication fault alarm display and online help troubleshooting are independent and self-managing manufacturing units.

9, <br> <br> new features in order to improve various aspects of performance CNC machine tool, with high accuracy and reliability of the application of new features become inevitable. Representative new features include:

High-frequency motor spindle: High-frequency motor spindle is the integration of high-frequency motor and spindle components, with a series of advantages of small size, high speed, stepless speed regulation, etc. It has been widely used in various new types of CNC machine tools;

Linear motors: In recent years, linear motors have become more widely used. Although their prices are higher than traditional servo systems, mechanical transmission structures have been simplified due to the application of key technologies such as load variation disturbance, thermal deformation compensation, magnetic isolation, and protection. The dynamic performance has improved. Such as: Siemens 1FN1 series of three-phase AC permanent magnet synchronous linear motor has been widely used in high-speed milling machines, machining centers, grinding machines, parallel machine tools and dynamic performance and high precision moving machine tools; Germany EX-CELL-O The company's XHC horizontal machining center three-way drive uses two linear motors;

Electric Ball Screw: The electric ball screw is an integration of servo motor and ball screw, which can greatly simplify the structure of CNC machine tools, and has a series of advantages such as less transmission links and compact structure.

10, <br> <br> high reliability compared with conventional CNC machine tools, and a corresponding increase in the numerical control system monitoring devices, application of a large electrical, hydraulic and electromechanical device, liable to cause an increase in probability of failure; Industrial network voltage fluctuations and interference are extremely unfavorable to the reliability of CNC machine tools, and the part surface of CNC machine tools is complex, the processing cycle is long, and the average time between failures is more than 20,000 hours. In order to ensure high reliability of CNC machine tools, it is necessary to carefully design the system, strictly manufacture and define the reliability objectives, and analyze and analyze the failure modes through maintenance and identify weak links. The average time between failures of foreign CNC systems is from 7 to 100,000 hours. The average time between failures of domestic CNC systems is only 10,000 hours, and the average total time between failures of foreign machines is more than 800 hours, while the domestic maximum is only 300 hours.

11, processing of green <br> <br> With increasingly stringent environmental and resource constraints, manufacturing and processing of the green more and more important, while China's resources and environment is particularly prominent. Therefore, in recent years, machine tools that do not use or minimize the use of coolant, dry cutting, and semi-dry cutting are becoming more and more important and continue to develop. In the 21st century, the major trend of green manufacturing will accelerate the development of various energy-saving and environmental protection machine tools and occupy more world markets.

12, multimedia technology applications <br> <br> set of computer multimedia technology, audio-visual and communications technology, and the computer has an integrated handle voice, text, image and video capability, and therefore also proposed a graphical user interface The request. Reasonable user-friendly user interface greatly facilitates the use of non-professional users, people can operate through windows and menus, and facilitate blueprint programming and rapid programming, three-dimensional color three-dimensional dynamic graphic display, graphic simulation, graphics dynamic tracking and simulation, different Directional view and partial display scaling. In addition, the application of multimedia technology in the field of numerical control technology can be integrated, intelligent information processing, applied to real-time monitoring systems and production field equipment fault diagnosis, monitoring of production process parameters, etc., so it has a significant application value.

The rapid development of CNC machine tools, high-speed, high-precision, composite, intelligent, open, parallel drive, networking, extreme, green has become the trend and direction of the development of CNC machine tools. China's CNC industry can not be satisfied with the status quo, it should seize the opportunity to continue development, and strive to develop their own advanced technology, increase technological innovation and personnel training, improve the company's comprehensive service capabilities, and strive to shorten the gap with the developed countries. We will strive to achieve the transition from low-end to high-end CNC machine tool products, from primary product processing to high-precision product manufacturing as early as possible, and realize the transition from manufacturing in China to creation in China, and from manufacturing to manufacturing.