Computerized numerical control (Computerized numerical control, referred to as CNC) system is a computer-controlled machining functions to achieve numerical control of the system.CNC system according to the computer memory stored in the control program, the implementation of some or all of the numerical control functions, and is equipped with interface circuits and servo drive device dedicated computer system.
CNC system consists of CNC program, input device, output device, computer numerical control device (CNC device), programmable logic controller (PLC), spindle drive device and feed (servo) drive device (including detection device) and other components.
The core of the CNC system is the CNC unit. As a result of the use of computers, the system has a software function, and PLC instead of the traditional machine tool electrical logic control device, so that the system is more compact, its flexibility, versatility, reliability is better, easy to realize the complexity of the numerical control function, the use of the maintenance is also convenient, and has the function of connecting with the host computer and remote communication.
Fourteen trends in machine tool technology
1, high-speed machine tools
With the automotive, aerospace and other industrial light alloy materials are widely used, high-speed machining has become an important trend in manufacturing technology. High-speed machining has the advantages of shortening the processing time, improve machining accuracy and surface quality, etc., in the mold manufacturing and other areas of application is also becoming increasingly widespread. High-speed machine tools require new CNC systems, high-speed electric spindles and high-speed servo feed drives, as well as optimization of the machine structure and lightweight. High-speed machining is not only the equipment itself, but the integration of machine tools, tools, shanks, fixtures and CNC programming technology, as well as the quality of personnel. The ultimate goal of high-speed is efficient, the machine tool is only one of the keys to achieve high efficiency, never all, productivity and efficiency in the "tip".
2, the precision of the machine tool
In accordance with the processing accuracy, machine tools can be divided into ordinary machine tools, precision machine tools and ultra-precision machine tools, processing accuracy of about every 8 years to double. Positioning accuracy of CNC machine tools is about to say goodbye to the micron era and enter the sub-micron era, ultra-precision CNC machine tools are marching to the nanometer. In the next 10 years, precision and high-speed, intelligent and miniaturized convergence of a new generation of machine tools. Precision of machine tools is not only automotive, electronics, medical equipment and other urgent needs of the industry, but also directly related to aerospace, missiles and satellites, new types of weapons and other defense industry modernization.
3, from process composite to complete processing
The machining centers appeared in the 70's to open the first multi-process integration, has been developed to complete processing, that is, in a machine tool to complete all the processing of complex parts. Complete machining through the process of integration, a card will be a part of the machining process is completed. As a result of reducing the number of times the card is loaded, improve the machining accuracy, easy to ensure the process of high reliability and realize the zero-defect production. In addition, complete machining shortens the machining process chain and auxiliary time, reduces the number of machine tools, simplifies the material flow, improves the flexibility of the production equipment, the total production footprint is small, so that the investment is more effective.
4, machine tool information technology
The typical case of machine tool information technology is the Mazak410H, the machine tool is equipped with an information tower, to achieve autonomous management of the workplace. The information tower has communication functions such as voice, text and video. It is networked with the production planning and scheduling system to download work instructions and machining programs. The machining process can be observed on the screen when the workpiece is test cut. The information tower reflects the working status of machine tools and processing progress in real time, and can be queried by cell phone. The information tower also carries out statistical analysis of workplace data and tool life management, as well as fault alarm display and online help troubleshooting. Fingerprint confirmation is required for machine tool operation privileges.
5, machine tool intelligence - measurement, monitoring and compensation
Machine tool intelligence includes online measurement, monitoring and compensation. CNC machine tool position detection and its closed-loop control is a simple application case. In order to further improve machining accuracy, the machine's circumferential motion accuracy and the spatial position of the tool head point can be compensated for by ballbar and laser measurements, which are fed into the CNC system. Future CNC machine tools will be equipped with a variety of miniature sensors to monitor the cutting force, vibration, thermal deformation and other errors generated, and automatically compensate or adjust the machine's operating state to improve the machine's operating accuracy and stability.
6, the miniaturization of machine tools
With the rapid progress of nanotechnology and microelectromechanical systems, the development of machine tools for processing micro-parts has been put on the agenda. Micro-machine tools at the same time with high speed and precision features, the smallest micro-machine tools can be placed in the palm of your hand, a micro-factory can be placed in the suitcase. The operator controls the entire factory through a joystick and a monitor screen.
7, the new parallel mechanism principle
Traditional machine tools are based on Cartesian coordinates will move along the three coordinate axes X, Y, Z and around the three coordinate axes rotating A, B, C sequentially superimposed in series, the formation of the desired tool movement trajectory. Parallel motion machine tools use various types of rod mechanisms to shift spindle parts in space to form the desired tool trajectory. Parallel motion machine tools have a series of advantages such as simple and compact structure, high stiffness, good dynamic performance, etc., and have a broad application prospect.
8, the new process
In addition to metal cutting and forging forming, new processing methods and processes are endless, the concept of machine tools are changing. Laser processing field is expanding, in addition to laser cutting, laser welding, laser hole processing, laser three-dimensional processing, laser heat treatment, laser direct metal manufacturing applications are becoming increasingly widespread. Electro-processing, ultrasonic processing, stacked milling, rapid prototyping technology, three-dimensional printing technology each show their skills.
9, new structures and new materials
Machine tool speed and precision requires the simplification of the structure of the machine tool and lightweight, in order to reduce the inertia of the machine tool components on the negative impact on the machining accuracy, and significantly improve the dynamic performance of the machine tool. For example, with the help of finite element analysis for topology optimization of machine components, the design of box-in-box structure, and the use of hollow welded structures or lead alloy materials have begun to move from the laboratory to practical.
10, new design methods and tools
China's machine tool design and development means to dump the board as soon as possible from the two-dimensional CAD to three-dimensional CAD transition. Three-dimensional modeling and simulation is the basis of modern design, is the source of technological advantage of enterprises. In this three-dimensional design based on the integration of CAD/CAM/CAE/PDM to speed up the development of new products, to ensure the smooth production of new products, and gradually realize the product life cycle management.
11, direct drive technology
In the traditional machine tool, the motor and machine components are connected with the help of coupling elements, such as belts, gears and couplings, etc., to achieve the required movement or rotation of the components, machine and electricity are separated. Direct drive technology is the motor and mechanical components into one, become a mechatronic functional components, such as linear motors, electric spindles, electric ball screws and torque motors. Direct drive technology simplifies the structure of the machine tool, improves the rigidity and dynamic performance of the machine tool, movement speed and machining accuracy.
12, open CNC system
The openness of the CNC system is the trend. Currently there are three forms of open CNC system: 1) full open system, that is, microcomputer-based CNC system, the microcomputer as a platform, using a real-time operating system, the development of a variety of functions of the CNC system, through the servo card to transmit data to control the movement of the coordinate axis motors. 2) Embedded system, that is, the CNC + PC, CNC control of the movement of coordinate axis motors, the PC as a human-machine interface and network communications. 3) Fusion system, in the CNC control of the movement of coordinate axes, PC as a human-machine interface and network communications. ) Fusion system, on the basis of the CNC to increase the PC motherboard, provide keyboard operation, improve the human-machine interface functions, such as Siemens840Di and Fanuc210i.
13, reconfigurable manufacturing system
With the accelerated rate of product replacement, the reconfigurability of the special-purpose machine tools and the reconfigurability of the manufacturing system is becoming increasingly important. Through the modularization of CNC machining units and functional components, the manufacturing system can be quickly restructured and configured to adapt to the production of variable products. Normalization and standardization of interfaces between mechanical, electrical and electronic, hydraulic and pneumatic, and control software are key to achieving reconfigurability.
14, virtual machine tools and virtual manufacturing
In order to speed up the development of new machine tools and the quality of the design stage with the help of virtual reality technology, can be in the machine tool has not been manufactured before, will be able to evaluate the correctness of the machine tool design and the use of performance, in the early discovery of a variety of mistakes in the design process to reduce losses and improve the quality of the development of new machine tools.
Focus on the scope of development
1, high-speed, precision CNC lathes, turning centers and more than four-axis linkage of composite processing machine tools. Mainly to meet the needs of aerospace, aviation, instruments, meters, electronic information and bioengineering industries.
2, high-speed, high-precision CNC milling and boring machine and high-speed, high-precision vertical and horizontal machining centers. Mainly meet the automobile engine cylinder block cylinder head and aerospace, high-tech industries such as large-scale complex structure bracket, shell, box, light metal material parts and precision parts processing needs.
3, heavy, ultra-heavy CNC machine tools: CNC floor milling and boring machine, heavy-duty CNC gantry boring and milling machine and gantry machining centers, heavy-duty CNC horizontal lathe and vertical lathe, CNC heavy hobbing machine, etc., this type of products to meet the energy, aerospace, military, naval host manufacturing, heavy machinery manufacturing, large-scale mold machining, turbine cylinder block and other industry parts processing needs.
4, CNC grinding machines: CNC ultra-precision grinding machines, high-speed and high-precision crankshaft grinding machines and camshaft grinding machines, various types of high-precision and high-speed special grinding machines to meet the demand for precision and ultra-precision processing.
5, CNC electric processing machine tools: large precision CNC EDM forming machine tools, CNC low-speed wire EDM cutting machine tools, precision small-hole electric processing machine tools, etc., mainly to meet the large and precision mold processing, precision parts processing, tapered holes or shaped holes, and aerospace, aviation and other industries, the special needs of the industry.
6, CNC metal forming machine tools (forging and pressing equipment): CNC high-speed precision plate stamping equipment, laser cutting composite machine, CNC spinning machine, etc., mainly to meet the automotive, motorcycle, electronic information industry, home appliances and other industries, sheet metal batch production needs and automotive wheel hubs and the military industry, a variety of thin-walled, high-strength, high-precision transformation of the parts processing needs.
7, CNC special machine tools and production lines: flexible machining automated production line (FMS / FMC) and a variety of special CNC machine tools, the production line for automotive, home appliance and other industries to process the cylinder, cylinder head, transmission case, and other multi-species variable batch shell, box parts processing needs.