Introduction to Basic Knowledge of Five-axis Machining Center

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In addition to the input of the machine tool itself, the five-axis wood pattern machining center must also upgrade the CAD/CAM system software and post-processor to meet the requirements of five-axis machining. It is necessary to upgrade the calibration program so that it can simulate the whole machine tool.

If axis A and axis C are connected with three straight axes of XYZ,

The grid of five-axis machining center of automobile tire mold can process complex spatial surfaces, and it certainly needs the support of high-grade CNC system, servo system and software. Machine tool is a symbol of a country's manufacturing level.

It conforms to the new development direction of CNC machine tools.

In recent years, international and domestic machine tool exhibitions show that the software training of five-axis machining center is developing in the direction of high speed, high precision and compound. However, in general, the workbench cannot be designed to be too large and its bearing capacity is small, especially when the A-axis rotation is greater than or equal to 90 degrees, the workpiece will bring great bearing capacity to the workbench when cutting.

Instantly. There is also a turntable in the middle of the workbench, which rotates around the Z axis, defined as the C axis, and the C axis rotates 360 degrees. In order to achieve the development goal of the Tenth Five-Year Plan, all localities urgently need to further develop CNC machining technology, and urgently need to configure a large number of various process equipment, especially CNC machine tools.

It is generally believed that the five-axis CNC machine tool system is the only means to solve the processing of impellers, blades, marine propellers, heavy generator rotors, steam turbine rotors and large diesel engine crankshafts.

From 1999, at CIMT, CCMT and other international and domestic machine tool fairs, domestic five-axis CNC machine tools products appeared one after another, and the domestic five-axis CNC machine tool market gradually opened up, followed by the arrival of international machine tool giants, and the variety and quantity of five-axis CNC machine tools increased year by year: CIM.

T99 and CCMT2000 introduced three kinds of domestic five-axis combined beds respectively. At CIMT200 1 International Machine Tool Expo, Beijing No.1 Machine Tool Works and Guilin Machine Tool Co., Ltd. respectively exhibited five-axis high-speed gantry machining centers with spindle speed of 10000r/min, and the spindle speed of Beijing Institute of Electromechanical Technology was 15.

000r/min five-axis high-speed vertical machining center; XNZ63 was jointly developed by Tsinghua University and Kunming Machine Tool Co.,

The five-axis machining center of casting mold adopts scale Stewart platform structure, which can realize six-degree-of-freedom linkage; Series and parallel machine tools developed by Dalian Machine Tool Works.

DCB-5 10, whose numerical control system is developed by Tsinghua University, realizes the linear motion of X, Y and Z axes through parallel mechanism and the rotary motion of A and C axes through series mechanism, thus realizing the five-axis linkage, and its linear fast feed speed can reach 80m/min. Even in developed industrialized countries, it is highly respected. Friends interested in military affairs may know the famous "Toshiba incident": at the end of last century, Toshiba sold several five-axis CNC milling machines to the former Soviet Union, and as a result, the propellers used by the former Soviet Union to manufacture submarines were upgraded by several grades, making it impossible for the sonar of American butterfly ships to monitor the sound of submarines. Therefore, the United States violated Toshiba's strategic material embargo policy and punished Toshiba. Therefore, whenever people encounter insurmountable setbacks when designing and developing complex surfaces, they often turn to the five-axis CNC system.

The other depends on the rotation of the vertical spindle head. Why is the five-axis numerical control technology not widely popularized for a long time? Because of the interference of machining space and tool position control, the NC programming, NC system and machine tool structure of five-axis NC machining are much more complicated than those of three-axis machine tools. In this way, through the combination of axis A and axis C, all five surfaces of the workpiece fixed on the workbench except the bottom surface can be machined by vertical axis. In recent years, with the rapid development of China's national economy and the need of national defense construction, there is an urgent and large demand for high-grade CNC machine tools. With the development of machine tool industry in China, the self-developed high-precision and sophisticated products have been involved in international competition, breaking the international technology monopoly. International machine tool giants don't want to lose China, which has great potential, so they flock to "deliver" their products: eight five-axis machining centers, 1 five-axis turning and milling centers and five five five-axis CNC tool grinders are exhibited in foreign exhibition halls. Recently, a new concept has emerged in the international machine tool industry, that is, universal machining. CNC machine tools can not only turn, but also carry out five-axis milling. At present, five-axis numerical control technology is developing worldwide.

The following problems generally exist in libraries. There are two ways to rotate the axis of machining center of vertical five-axis machining center, one is the axis of table. The goal of compound machining is to complete most or all cutting by clamping on one machine tool at a time, so as to ensure the position accuracy of the workpiece and improve the machining efficiency. In the process of NC machining, users often need to change tools or adjust the cutting size of tools. According to the normal machining procedure, the tool path should be sent back to the CAM system for recalculation. At present, the numerical control system of the popular five-axis machining center for musical instruments can't complete the tool radius compensation, because the ISO file doesn't provide enough data to recalculate the tool position. Now a three-axis machine tool with a rotating shaft is basically the price of an ordinary three-axis machine tool, which can realize the function of a multi-axis machine tool. However, in recent years, with the breakthrough development of computer-aided design (CAD) and computer-aided manufacturing (CAM) systems, many domestic numerical control enterprises, such as Xing Shan Company, have launched five-axis numerical control machine tool systems, which broke the technical closure of foreign countries, occupied the highest point of this strategic industry, and greatly reduced its application cost, thus bringing China equipment manufacturing industry into a brand-new era! The development of modern science, represented by information technology, has injected a strong impetus into the equipment manufacturing industry, and at the same time put forward stronger requirements for it, further highlighting the irreplaceable basic role of machinery and equipment manufacturing industry as a carrier of high-tech industrialization in promoting the technological progress and industrial upgrading of the whole society. At present, the application of five-axis CNC machine tools is limited to aviation, aerospace and related industries. These machine tools have reached the international advanced level, reflecting the strength of China's machine tool industry in providing equipment for the development of cutting-edge national defense industries and making breakthrough progress. When using cylindrical milling cutter for contact forming milling, it is necessary to compile different programs for tools with different diameters. Expanding the five-axis linkage function on the machining center can greatly improve the machining capacity of the machining center and facilitate the further integration of the system. As the driving force of national economic growth and technological upgrading, the machinery and equipment manufacturing industry marked by five-axis linkage will be improved with the development of high-tech and emerging industries. The practical application of five-axis CNC machine tools at home and abroad shows that its processing efficiency is equivalent to two three-axis machine tools, and it can even completely save the investment of some large-scale automatic production lines, greatly saving the time and cost of occupying space and transporting workpieces between different manufacturing units.

Development and Market Analysis of Five-axis NC Technology in China

Five-axis CNC machine tools are central processing equipment urgently needed by civil and military industries such as electric power, ships, aerospace and high-precision instruments. The five-axis CNC machine tool system, which represents the highest level of machine tool manufacturing, reflects the industrial development level of a country in a certain sense.

For decades, people generally believe that five-axis NC machining technology is the only means to process continuous, smooth and complex surfaces. The workbench arranged on the lathe bed can rotate around the X axis, which is defined as the A axis, and the general working range of the A axis is +30 degrees to-120 degrees. China should not only be a manufacturing power in the world, but also a manufacturing power in the world! It is predicted that in the near future, with the popularization of the five-axis CNC machine tool system, it will surely lay a solid foundation for China to become the most powerful country in the world!

Machining centers are generally divided into vertical machining centers and horizontal machining centers. The most effective machining surface of vertical machining center (three-axis) is only the top surface of workpiece, and horizontal machining center can only finish the four-sided machining of workpiece with the help of turntable. Three-axis machine tools only have linear coordinate axes, and five-axis CNC machine tools have various structural forms; Unified NC code can achieve the same machining effect on different three-axis NC machine tools, but the NC code of a five-axis machine tool can not be applied to all types of five-axis machine tools. Western developed countries have imposed an embargo on China for a long time. Internationally, five-axis CNC technology is regarded as a symbol of the automation level of production equipment in a country. This design also has a great advantage: when we use the spherical milling cutter to process the curved surface, when the center line of the cutter is perpendicular to the machined surface, the surface quality of the workpiece cut by the vertex will be poor because the linear velocity of the vertex of the spherical milling cutter is zero. Through the design of spindle rotation, the five-axis machining center for glass fiber reinforced plastic trimming makes the spindle rotate at an angle relative to the workpiece, so that the spherical milling cutter can avoid vertex cutting, ensure a certain linear speed and improve the surface machining quality. In addition to linear motion, NC programming should also coordinate the calculation of rotary motion, such as the maintenance of rotary angle and stroke, the inspection of nonlinear error, the calculation of cutter rotary motion and so on. It deals with a lot of information and is extremely abstract. But so far, the application of five-axis CNC technology is still limited to a few parts with abundant funds, and there are still unresolved setbacks. Because of its special position, especially its important influence on aviation, aerospace and military industry, and its technical complexity, it is one of the developed countries in the west.

Five-axis CNC system is directly used as a strategic material to implement export license system and embargo on China. At present, the high-grade machining center is developing in the direction of five-axis control. The five-axis linkage machining center has the characteristics of high efficiency and high precision, and the pentahedron can be machined by clamping the workpiece once.

The overall application level of CNC technology and equipment in various industries in China is still low, and there is still a big gap compared with developed countries. Resulting in very low efficiency of the whole processing process. Because the five-axis CNC machine tool system is very expensive and it is difficult to make CNC programs, it is difficult to apply the five-axis CNC machine tool system.

What are the difficulties and obstacles to development and popularization?

Obviously, people have long been familiar with the superiority and importance of five-axis CNC technology. Once people encounter insurmountable setbacks when designing and manufacturing complex surfaces, they will turn to five-axis machining technology. The main technical requirements for CNC machine tools are multi-axis, high speed, good rigidity and high power; The demand for coordinate numbers is mainly based on three to five axes linkage.

Buying machine tools requires a lot of investment.

In the past, there was a big price gap between five-axis machine tools and three-axis machine tools.

Tool radius compensation problem

In the five-axis NC program, the tool length compensation function is still valid, but the tool radius compensation is invalid. As early as 1960s, five-axis CNC milling machine was used in foreign aviation industry.

Equipment manufacturing industry is the cornerstone of a country's industry, which provides an important means for the development of new technologies and new products and modern industrial production, and is an indispensable strategic industry. Five-axis machining training Foreign CNC boring and milling machines and machining centers all adopt multi-axis machining technology, including five-axis linkage function, to adapt to the machining of polyhedral and curved parts. The advantage of this arrangement is that the spindle processing is very flexible and the workbench can be designed to be very large. The huge fuselage and engine shell of passenger plane can be processed in this machining center. Therefore, it is of great significance to study the five-axis NC machining technology for the progress of national scientific and technological strength and comprehensive national strength.

The final solution of this problem depends on the introduction of a new generation of CNC system, which can identify the general patterns of workpiece model files (such as STEP, etc.). ) or CAD system files. Especially during the infighting, China, the former Soviet Union and other Eastern blocs were closed and embargoed.

Five-axis numerical control is the most difficult and widely used technology in numerical control technology. It integrates computer control, high-performance servo drive and precision machining technology, and is suitable for efficient, precise and automatic machining of complex surfaces. For industries with complex hub parts, such as aviation, electric power, shipbuilding, mold manufacturing, etc. In the production part, the demand for multi-axis machine tools is relatively large, and the newly added five-axis CNC machine tools account for about 70% ~ 80% of the total number of CNC machine tools. In order to achieve high rotation accuracy, the high-grade rotating shaft is also equipped with circular grating ruler feedback, and the indexing accuracy is within a few seconds. Of course, the rotary structure of this spindle is more complicated and the manufacturing cost is higher. For a long time, western industrialized countries led by the United States,

The five-axis machining center of automobile tire mold has always regarded the five-axis CNC machine tool system as an important strategic material and implemented the export license system. If equipped with five-axis high-grade CNC system, it can also process complex spatial surfaces with high precision, which is more suitable for processing modern molds such as automobile parts and aircraft structural parts.

Abstraction and operation of five-axis NC programming

This is a headache for every traditional NC programmer. This structure is very suitable for high-precision surface machining of molds, but it is difficult for the rotary machining center of the workbench to do this. At the same time, the price of five-axis machine tools is only 30% ~ 50% higher than that of three-axis machine tools.

The minimum dividing value of axis A and axis C is generally 0.00 1 degree, and the workpiece can be subdivided into arbitrary angles to process inclined planes and inclined holes. It can be seen that the five-axis CNC machine tool system has a decisive influence on a country's aviation, aerospace, military, scientific research, precision instruments, high-precision medical equipment and other industries.

Five-axis machining center price. The front end of the spindle is a rotating head, which can rotate 360 degrees around the Z axis to become the C axis. The rotating head also has an A axis, which can rotate around the X axis, generally reaching more than 90 degrees, achieving the same function as mentioned above. The advantages of this arrangement are that the structure of the spindle is relatively simple, the rigidity of the spindle is very good, and the manufacturing cost is relatively low.