毕业论文英文翻译资料.doc

桂林电子科技大学毕业设计论文英文翻译资料CNC machine tools, CNC engravingmachine overview History of the development of CNC machine tools and necessity: half a century,CNC system has gone through two stages, six generations of development.Hard-line CNC phase (1952 to 1970). The initial computer processing speed is relatively low because, for real-time control of machine-wide fashion. So, people have to use digital logic circuits, ride into a dedicated computer as numerical control machine tool system, known as the hard-line numerical control (Hardwired Numerical Control), referred to as NC (NC). With the development of components, this stage of development through three generations, beginning in 1952 that the first generation of numerical control system, its main feature is the tubes, relays, analog circuit elements based; the second generation in 1959, CNC Its main feature is a transistor-based digital circuit elements; 1965, the third generation CNC system, its main features is the integrated digital circuit devices based. Computer numerical control phase (1970-present). 1970 the fourth generation CNC system, its main feature is a small computer-based and small-scale integrated circuits using CNC; 1974, the fifth generation of numerical control system, its main features are based on microprocessor and a digital display, fault self-diagnostic function numerical control systems; 1990, the sixth generation of numerical control system, which is characterized by a PC-based CNC system, now widely used to enter the stage, the price is relatively much lower, and for some large-scale equipment, the high-precision, versatile, easy to operate, develop simple, easy and so the price is very high, and some can reach millions or even thousands of yuan. The need for the development of CNC machine tools: (1): World War II reflected the demands of more sophisticated weapons and equipment; computer technology generation and continuous development; machine technology continues to evolve and mature and so on. (2): World War II reflected the demands of more sophisticated weapons and equipment; computer technology generation and continuous development; machine technology continues to evolve and mature and so on. CNC features:Digital control machine tool CNC machine tools is short, is a process control system with automated machine tools. The control system can deal with control logic or other symbolic instruction code procedures prescribed and decoding, so that the machine movement and processing of parts. CNC machine tool control unit:CNC machine operation and monitoring of all completed in the numerical control unit, which is the brain of CNC machine tools. Compared with ordinary machine tools, CNC machine tools has the following characteristics: high precision, stable processing quality; can be multi-axis linkage, can process complex shape of the parts; processing part changes, generally only need to change the NC program, saving production time to prepare; high precision machine itself, rigidity, choose the amount of benefit processing, production rate (usually for ordinary machine 3 to 5 times); high degree of automation tools, can reduce labor intensity; the quality of higher operators, maintenance personnel of higher technical requirements.CNC machine tools generally consists of the following components: host, he is the subject of CNC machine tools, including machine tools, column, spindle, feed mechanism and other mechanical parts. He is used to complete a variety of machining mechanical parts. CNC equipment, CNC machine tools is the core, including the hardware (printed circuit boards, CRT monitors, key boxes, paper tape reader, etc.) and the corresponding software, enter the number of parts used in the program, and complete input information storage, data transformation, interpolation operation and to achieve a variety of control functions. drive, he is a CNC machine tool actuators drive components, including the spindle drive unit, feed unit, the spindle motor and feed motor and so on. He was under the control of the NC device electrical or electro-hydraulic servo system to achieve through the spindle and feed drive. When the linkage of several feed, you can complete the position, line, plane curves and space curves processing. assist device, the index-controlled machine tools necessary supporting components to ensure the operation of CNC machine tools, such as cooling, chip removal, lubrication, lighting, monitoring and so on. It consists of hydraulic and pneumatic devices, chip conveyor, pallet, NC rotary table and CNC dividing head, including testing tool and monitoring devices. programming and other ancillary equipment used to make parts in the machine outside the programming, storage, etc. CNC milling and engraving machine introduction: CNC milling machine concept: milling CNC milling machine is generally developed on the basis of the two are basically the same processing technology, the structure is also somewhat similar, but the CNC milling machine is controlled automatically by the machine tool program, so its structure and general milling machine with generally very different from CNC milling machine CNC system, the main drive system, servo feed system, cooling and lubrication systems of several major components: (1), including the spindle head and the headstock spindle drive system for clamping tool and drive tool rotation, spindle speed range and the output torque has a direct impact on the process. (2), the feed motor servo system consists of feed and feed executing agencies, according to the procedures set feed rate to achieve between the tool and the workpiece relative motion including linear feed movement and rotation. (3), the control system motion control CNC milling centers, CNC machining program execution control of the machine for processing. (4), assistive devices such as hydraulic, pneumatic, lubrication, cooling and chip removal, protective and other equipment. (5), usually refers to pieces of the machine base foundation, columns, beams, etc., it is the foundation and framework for the entire machine. CNC milling machine classification: The classification is usually milling spindle axis direction according to points, if the vertical to the horizontal plane is called the CNC vertical milling machine; if parallel to the horizontal plane is called the CNC horizontal milling machine; there two vertical and horizontal with the CNC milling machine, but relatively rare. The CNC milling machine CNC vertical milling machine is the largest number in a range of applications most widely used. Generally use a small CNC milling machine table moves, way down and the spindle rotation, and general organization similar to the vertical milling machine; medium-sized CNC vertical milling machine commonly used way to vertically and horizontally moving table, and slide along the vertical axis on the motion, and gantry is for vertical movement along the bed. Vertical CNC milling machine vertical milling machine can be general-coordinate CNC vertical milling machine in the majority. In addition, the spindle can rotate around the X, Y, Z axis in one or two for the death of NC rotary movement coordinates and five-axis CNC vertical milling machine. In general, the machine axis, the more control, particularly those that require more joint axes, the machine function, processing area and choose the more the object of processing. However, the attendant is more complex machine tool structure, the numerical control system requirements are higher, more difficult programming, equipment prices higher. CNC Vertical Milling Machine CNC turntable can also be attached, automatic switchboard, increasing by mode devices to expand its functionality, processing area and processing of objects to further improve production efficiency. Horizontal CNC milling machine and CNC milling machine class the same universal horizontal milling machine, the spindle axis parallel to the horizontal plane. In order to expand the scope and expansion of processing capabilities, CNC horizontal milling machine commonly used to increase or universal CNC CNC rotary dial to achieve four or five-axis machining. This will not only continuous rotation on the side of the workpiece contour can be processed out, and can be achieved in an installation, change the station by the turntable, the four processing. Universal CNC turntable, especially on the workpiece can be different angle or space angle of the machined surface placed into a level of processing. This can save a lot of special fixtures or special angle milling cutter. For box-type parts or need to work in an installation position of the workpiece changes, the choice of CNC rotary table with horizontal milling machine is suitable for processing. As the horizontal CNC milling machine CNC turntable after the addition of the workpiece is very easy to do, four processing, in many ways better than the wheel with CNC vertical milling machine, it has been a lot of user attention. Li, lying dual digital now, this type of milling machine is gradually increased. Since this type of milling machine spindle orientation can be replaced to achieve in a single machine can be either vertical machining, horizontal machining can be there to make a wider range of applications, more whole, more room for the object selection process, gives users a lot of convenience. Especially when production volume is small, varieties, there is need to stand, lie two ways to process, users simply buy a machine like it. Li, lying dual spindle CNC milling machine direction of the transformation of manual and automatic methods, the use of CNC universal spindle head up, horizontal dual-use CNC milling machine, the spindle head can be any changes of direction, can be processed and appear before a variety of levels different angles of the workpiece surface. When established, increased horizontal CNC milling CNC dual wheel, the workpiece can be achieved five-sided machining. That in addition to positioning the workpiece in contact with the wheel surface, other surfaces can be processed in a single installation. Therefore, the processing performance is excellent. CNC milling machine structural characteristics: high stiffness and high stiffness of vibration of the milling machine is one of the technical performance of milling machine, milling machine structure which reflects the ability to resist deformation. According to the different nature of the load suffered milling, milling in force under static stiffness as shown by the mill stiffness; milling force in the dynamic stiffness performance under the milling machine called the dynamic stiffness. Commonly used in the milling machine milling machine performance tests to demonstrate the compliance of the milling performance, flexibility is the reciprocal of stiffness. CNC milling machine to meet the high-speed, high accuracy, high productivity, high reliability and high automation, compared with ordinary milling machine, CNC milling machine should have a higher static and dynamic stiffness, better vibration resistance. CNC milling machine to improve structural rigidity of the measures are the following: 1) improve the milling component stiffness and natural frequency. Improve the structure or layout of the weak links in order to reduce exposure to the bending load and torque load. For example, the CNC milling machine spindle box or ram and other components, can be used to balance the load unloading device to compensate for changes in components due to static, unloading devices are commonly used hammer and balanced hydraulic cylinder; improve the contact between the stiffness of the component and milling junction with the foundation stiffness. 2) to improve the damping characteristics of the structure of CNC milling machine. In the large cavity filled with clay core and concrete damping material, the vibration due to the relatively large friction and vibration energy dissipation. Damping coating method can also be used, that is, in large surface coating layer with high damping and high flexibility to increase the viscosity of the material damping ratio. 3) the use of new materials and structural steel welding.Reduce the impact of thermal deformation of milling machine milling machine milling affect the thermal deformation is an important factor in precision. As the CNC milling machine spindle speed, feed rate much higher than ordinary milling machine, and a large amount of cutting chips produced by the hot parts of the workpiece and the milling effect of heat conduction serious than ordinary milling machine, and thermal deformation of the impact of precision is often difficult to correct. Therefore, the operator should pay particular attention to reducing the impact of thermal deformation of CNC milling machine. Commonly used measures are the following: improving the layout and structure of the milling machine hot-symmetrical structure, this structure is symmetrical relative to the heat source. In the thermal deformation, the workpiece or tool rotation center line of symmetry of the position remained unchanged, thus reducing the impact on the accuracy of the workpiece.The tilt bed and skateboard ramp structure.The heat balance measures. control the temperature. Parts of milling heat (such as spindle boxes, etc.), the use of heat, air and liquid cooling and other control measures to absorb the heat source temperature of the heat issue. It is widely used on various types of CNC milling machine to reduce the thermal deformation of a response. take a strong position on the cold cutting measures. In the large amount of cutting machining, fall table, on a bed of hot chips and other components is an important heat source. CNC milling machine is now widely used multi-nozzle, high-volume coolant to cool the hot chip and exhaust, coolant and cooling cycle with a large-capacity refrigeration or cooling device to control the temperature. thermal displacement compensation. Predict thermal deformation, a mathematical model into the computer for real-time compensation.Simplify the structure of transmission machinery: CNC milling machine spindle drive and feed drive system, namely AC, DC and servo motor drives the spindle motor, these two types of motor speed range, and variable speed, so the headstock , the feed gearbox and transmission system greatly simplified box structure is simple, gears, bearings and shaft parts do not even have a significant decrease in the number of gears, driven by the motor directly to the ball screw spindle or feed. High transmission efficiency and seamless gear: CNC milling machine at high feed rate, the work for a smooth and high positioning accuracy. Therefore, the feeding system in the mechanical transmission devices and components requires a high life, high stiffness, seamless, high sensitivity and low friction characteristics. Currently, CNC milling machine feed drive system commonly used in three main mechanisms: ball screw, static worm - worm of institutions and pre-load dual-gear - rack. Low coefficient of friction of rail: rail milling machine milling machine is one of the basic structure. Milling accuracy and life is largely determined by the quality of rail milling machine. Performance in high-speed feed without vibration, low feed does not crawl, high sensitivity, can work in long-term continuous heavy loads, higher abrasion resistance, better accuracy retention and so on. Modern CNC milling machine used rail, rail and general milling machine is similar to the main use of a sliding rail, rail rolling and static pressure guide three, but in the material and structure has undergone a qualitative change. CNC turning and milling of the structural characteristicsCNC milling machines main spindle motor drive system is the driving force behind the drive to become available through the cutting and cutting with the cutting torque. In order to meet the processing of different materials and different processing methods, the main drive system requires CNC milling machine to have a wide speed range and the corresponding output torque. In addition, clamping the tool spindle unit directly to the cutting of the workpiece, and thus the quality of the processing (including processing roughness) and the tool life have a great impact, so the main drive system requirements are very high. In order for the efficient processing of high precision, low roughness of the workpiece, must have a good performance of the main drive system and a high accuracy, high stiffness, vibration, heat distortion and noise components can meet the needs of the spindle . the main characteristics of transmission system CNC milling machines main drive system generally use DC or AC spindle motor, belt drive and shaft through the gear box to drive the spindle. As the motor speed range, but also variable speed, making the structure of the spindle box greatly simplified. Spindle motor at rated speed and maximum torque output of all power, with the speed of change, power and torque will change. The regulator within the range (from rated speed to the minimum speed) for the constant torque, the torque is proportional with the speed down; in the speed range (from rated speed to the maximum speed) is constant power, torque rise with the speed high proportional decrease. This variation is consistent with the normal processing requirements, that the required torque, low speed cutting, high-speed cutting power consumption large. Motor can also be seen that the effective speed range is not necessarily able to fully meet the o