Introduction to the generation of nc machine tools and development

Nc machine is developed on the basis of ordinary machine tool, because it has good flexibility, high machining precision and stability, can process complex parts, reduce the labor intensity of the workers, and easy to realize modernization management and a series of advantages, the current has been widely used in mechanical manufacturing industry.The world’s first computer was born in 1946, let the human into the information society, six years later, the computer technology used in machine tools, from then on, the nature of traditional machine tools produced change, half a century on, the numerical control machine tool of the two phases and six generations of development.Especially in 1970, general small computer industry began to develop, computing speed is greatly increased, and transplanted it into the core component of numerical control system, since has entered the phase of computer numerical control (CNC), until now, the sixth generation, nc machine tools based on PC.Along with the development of computer technology, numerical control machine tool technology is also the development of corresponding, and constantly using the control theory of the computer, the latest technical achievement, improving its performance, application field is more and more broad, in order to meet the demand of new markets, new requirements, the current world of CNC technology and its equipment is developing towards the following characteristics: 1) high speed, high efficiency, high precision and reliability.Which is embodied in the spindle high speed, high feed speed, high speed and high transfer speed.2) modular, intelligent, flexible and integration.3) open.4) a new generation of numerical control processing technology and equipment.At present, the United States, Japan and Germany are in the world today in the numerical control machine tool of scientific research, design, manufacture and use the most advanced technology and experience the most rich countries.Because of the different social conditions, have their own characteristics.The United States government attaches importance to the development of machine tool industry, the department of defense and some because of its military needs, proposed the development direction of machine tool, the scientific research task, and provide sufficient funding, the online world of talent, focus on efficiency and innovation, combined with advanced computer technology, so the leading machine tool manufacturing industry;The German government has always attached importance to important strategic position of the machine tool industry, fostering energetically in many aspects, especially the combination of theory and practical application of basic research and applied research and technology, closely combine enterprises and scientific research departments, in the numerical control machine tool in-depth study on the commonness and characteristics of the problem, to excellence in quality.Germany’s nc machine tools, advanced applicable, real quality and performance is good, export all over the world, especially the Siemens company is famous all over the world;Japan in importance to talents and form a complete set of machine tool components on learning German, study American on quality management and numerical control technology, the result was better in some ways and is better than blue;In the aspect of nc machine tools in China and the western developed countries have a big gap, for three consecutive years in China since 2002 to become the world’s machine tool consumption and imports the first big country, we need to see the situation, fully aware not home-made numerical control machine, efforts to develop advanced technology and equipment, to narrow the gap with developed countries.Nc machine tools are usually program carrier, CNC equipment, servo system, detection and feedback device, auxiliary equipment, machine tool of ontology.Carrier program is used to access parts processing program of device, the device can be process in a certain format and code stored in the carrier, the carrier program can be a disk, tape, hard disk and flash memory CARDS, etc.;CNC unit is the core of the automatic processing machine tool, is the soul of the nc machine tools.The main control system mainly consists of CPU, memory, controller, etc.Numerical control system is the main control object position, Angle and speed, such as mechanical quantity and physical quantities, such as temperature, pressure and flow rate. The control mode and can be divided into data processing control and sequential logic control two kinds big.One of rolling repair module within the master controller is based on the read in parts of the program, through the decoding, compile processing, such as tool path interpolation operation is performed, and with the coordinate the position of the servo system, the comparison of speed feedback signal, so as to control machine tool the displacement of each coordinate axis.Servo system is the numerical control system and machine tool electric contact transmission link between ontology. Mainly driven by servo motor, control system and position detection and feedback device, etc. The servo motor is the system of executive element, is the power source of the servo motor drive control system. The numerical control system signal instructions compared with position feedback signal as displacement instructions, after again after driving system of power amplifier, driving motor running, through mechanical transmission device to drive a table or head movement.Detection and feedback device is beneficial to improve the machining precision of the nc machine tool, the guide rail and the moving track of spindle parameters detected, with one hundred city digital signal feedback to the CNC device, according to the feedback information.Auxiliary control unit receives the nc device is the main purpose of the switch output signals, compiled, and determine the logic, then through power amplifier drive after the corresponding electrical appliances, to drive the machine mechanical, hydraulic, pneumatic and other auxiliary equipment to complete the on-off action specified by the instruction.These controls include variable-speed of spindle moving parts, reversing and start-stop instruction, the choice of cutting tool and swap instructions, cooling and lubricating system of start stop, loosen, clamping workpiece and machine tool parts, dividing workbench transfer degree and other auxiliary motion of the switch.Nc machine tool similar to conventional machine tools, machine tools ontology by main shaft transmission device, feeding device, bed, table, and the auxiliary motion device, hydraulic pneumatic system, lubrication system, cooling device, etc.But nc machine tool in the overall layout, exterior modelling, the structure of transmission system, cutting tool system and operating mechanism and so on have been great changes have taken place.Change in order to meet the requirements of nc machine tools and give full play to the characteristics of nc machine tools.Working principle of the nc machine tools, CNC factory processing parts, the first should be woven processing parts geometry information and technology of the information processing procedures, have input device to the numerical control system, through the processing of numerical control system, operation, according to each component to the axis of the coordinate system in the drive circuit, zoom in on the servo motor drive, drive, each axis movement and feedback control, cutting tool and the workpiece and other devices strictly according to the regulations of the process sequence, trajectory and parameters in an orderly way, thus processing all of the parts contour.Nc machine tools has been more and more used in modern manufacturing industry, and play the incomparable advantage over ordinary machine tool, CNC machine tools mainly has the following characteristics: 1) transmission chain is short, compared with the ordinary machine tools spindle driver is no longer the motor speed, but the horizontal and vertical feed respectively driven by two electric servo motor movement.2) high rigidity, in order to match the numerical control system of high precision, numerical control machine tools of high rigidity, in order to adapt to the processing of high precision.3) drag, head ball screw pair adopted in moving, friction small, mobile light.At the ends of the lead screw bearing type bearing, its pressure Angle is larger than the ordinary bearing, chosen when it in the factory.Numerical control machine using oil mist lubrication part of the automatic lubrication, these measures have made numerical control machine tool moving light.The numerical control machine tool processing characteristics: 1) high degree of automation, can reduce the physical labor intensity of operators.Nc machining process is according to the input program automatically, the operator just starting on the knife, and replacement of cutting tools, loading and unloading workpieces in machining process, main is to observe and supervision and machine operation.However, because of nc machine tools of high technical content, the operator of the mental Labour increase.2) the processing parts with high precision, stable quality.Nc machine tool positioning accuracy and repeat precision is high, easy to guarantee the consistency of a batch of parts size, as long as the process design and procedure correct and reasonable, and careful operation, can guarantee the accuracy of parts and higher, also facilitate to carry on quality control process.3) high production efficiency.Numerical control machine is to be able to once again clamping in multiple machining surface, generally only testing first, so can provinces ordinary machine tool processing when a lot of middle process, such as line size detection, to reduce the auxiliary time, and because the nc machining of parts with stable quality, bring convenience for the follow-up process, the comprehensive efficiency improved significantly.4) facilitate new product development and modification.Generally don’t need a lot of complex numerical control processing technology and equipment, through the processing program can be the complicated shape and high precision parts processing, when the product modification, changes to the design, as long as the change program, without the need to design tooling.So, nc machining can greatly shorten the product development cycle, for new product research and development, product improvement, provides a shortcut.Suitable for the numerical control machine tool processing parts: 1) the most suitable for many kinds of medium and small batch parts.As nc machine tools in manufacturing costs decline gradually, now both here and abroad, processing of large quantities of parts is also has emerged.When processing small batch and single production, such as can shorten the debugging time and tooling preparation time can be chosen.2) high precision parts.Used in nc machine tool’s rigidity, manufacturing high accuracy, precision of the knife, can compensate the size, so can work require high dimensional accuracy of parts.3) the surface roughness value of small parts.In the workpiece and tool materials, finish machining allowance and tool Angle certain circumstances, the surface roughness depends on the cutting speed and feed speed of ordinary machine tool is a constant rotational speed, diameter of different cutting speed is different, like numerical control lathe with constant cutting function, surfacing, different diameter cylindrical can use the same linear velocity, ensure that the surface roughness value was small and consistent.When processing the surface roughness of different surface roughness of the surface of the small and the use of small feed speed, roughness of surface with larger feed rate, variability is very good, so it is difficult to do in ordinary machine tools.4) contour shape of complex parts.Any plane curve can be in a straight line or arc approximation, numerical control machine with circular arc interpolation function, can processing all kinds of complex profile parts.Conclusion: for the numerical control industry of our country, it is necessary to make the domestic numerical control system is advanced, reliable, vigorously promotes the quality of products and accessories, lay a technical foundation.Recently emphasized groundwork, build credibility, enlarge the market share of domestic CNC machine tools, the forward seek to surpass the advanced world level, striding towards the world market;Must vigorously promotes the fundamental, insist on & other;People-oriented & throughout;, accelerate improving personnel quality, cultivating various talents for experts, fundamentally change the current inefficient and backward state.People is fundamental to all business success or failure, layer upon layer are seriously & otherPeiCai, talent selection, relief of & throughout;, establishing the learning-type enterprise, setting up enterprise culture, accelerate the breeding, training on-the-job personnel.