Five-axis linkage CNC machine tool is a high-tech, high-precision machine tool specially used for processing complex curved surfaces. This machine tool system is useful for a country’s aviation, aerospace, military, scientific research, precision equipment, high-precision medical equipment, etc. The industry has a decisive influence. At present, the five-axis linkage CNC machine tool system is the only means to solve the processing of impellers, blades, marine propellers, heavy generator rotors, steam turbine rotors, large diesel engine crankshafts, and so on.
The equipment manufacturing industry is the cornerstone of a country’s industry. It provides important means for the development of new technologies, new products, and modern industrial production. It is an indispensable strategic industry. Even the developed and industrialized countries attach great importance to it. With the rapid development of the national economy and the needs of national defense construction, there is an urgent large-scale demand for high-end CNC machine tools. Machine tools are a symbol of the level of manufacturing in a country.
The highest level of machine tool manufacturing industry is the five-axis linkage CNC machine tool system. In a sense, it reflects a country’s industrial development level. For a long time, Western industrialized countries headed by the United States have always regarded the five-axis linkage CNC machine tool system as an important strategic material and implemented an export license system. Especially during the Cold War, a blockade and embargo were imposed on China, the former Soviet Union and other socialist camps. Military-loving friends may know the famous “Toshiba Incident”: At the end of the last century, Toshiba of Japan sold several five-axis CNC milling machines to the former Soviet Union. As a result, the former Soviet Union used to make submarine propulsion propellers to several grades. So that the sonar of the American spy ship could not monitor the sound of the submarine, so Toshiba of the United States violated the strategic material embargo policy and ordered Toshiba to be punished.
The Classification Of 5 Axis Cnc Machine
There are cradle type, vertical type, horizontal type, NC table+NC indexing head, NC table+90°B axis, NC table+45°B axis, NC table+A axis, two-axis NC spindle, etc.
- (1) Double swing head form (+A ,+C)
- (2) Swing head type (+B, +C tool)
- (3) Double turntable form (NC table)
- (4) Overhanging worktable (+B ,+CNC worktable)
- (5) One pendulum and one rotation form (+A, NC workbench)
5 Axis Cnc Machining Center
The five-axis machining center has the characteristics of high efficiency and high precision, and the workpiece can be processed in a pentahedron in one clamping. If equipped with a five-axis linkage high-end numerical control system, it can also perform high-precision processing of complex spatial surfaces, and is more suitable for processing modern molds such as auto parts and aircraft structural parts. There are two ways for the rotary axis of the vertical five-axis machining center. One is the table rotary axis. The table set on the bed can rotate around the X axis, which is defined as the A axis. The general working range of the A axis is +30 degrees to- 120 degrees.
There is also a turntable in the middle of the worktable, which rotates around the Z axis at the position shown in the figure, which is defined as the C axis, and the C axis rotates 360 degrees. In this way, through the combination of A-axis and C-axis, except for the bottom surface of the workpiece fixed on the worktable, the other five surfaces can be processed by the vertical spindle. The minimum indexing value of A-axis and C-axis is generally 0.001 degrees, so that the workpiece can be subdivided into any angle, and inclined surfaces, inclined holes, etc. can be processed.
If the A-axis and C-axis are linked with the XYZ three linear axes, complex spatial surfaces can be processed. Of course, this requires the support of high-end CNC systems, servo systems and software. The advantage of this arrangement is that the structure of the main shaft is relatively simple, the rigidity of the main shaft is very good, and the manufacturing cost is relatively low. However, the general worktable cannot be designed too large, and the load-bearing capacity is also small, especially when the A-axis rotation is greater than or equal to 90 degrees, it will bring a large load-bearing moment to the worktable when the workpiece is cut. The other is to rely on the rotation of the vertical spindle head. The front end of the spindle is a revolving head, which can circle the Z axis 360 degrees to become the C axis. The revolving head also has an A axis that can rotate around the X axis, which can generally reach more than ±90 degrees to achieve the same function as above. The advantage of this setting method is that the spindle processing is very flexible, the worktable can also be designed to be very large, and the huge fuselage and huge engine shell of the passenger aircraft can be processed on this type of machining center.
This design has another big advantage: when we use a spherical milling cutter to process curved surfaces, when the center line of the tool is perpendicular to the processing surface, since the linear velocity of the apex of the spherical milling cutter is zero, the surface quality of the workpiece cut by the apex will be poor. The spindle rotation design is adopted to make the spindle rotate at an angle relative to the workpiece, so that the spherical milling cutter avoids the apex cutting, guarantees a certain linear speed, and improves the surface processing quality. This structure is very popular for high-precision surface processing of molds, which is difficult for rotary table machining centers to achieve. In order to achieve the high precision of rotation, the high-end rotary axis is also equipped with circular grating scale feedback, and the indexing accuracy is within a few seconds. Of course, the rotation structure of this type of spindle is more complicated and the manufacturing cost is also high.
The Development Status Of 5 Axis Cnc Machine
Foreign five-axis linkage CNC machine tools appeared to adapt to the processing of polyhedrons and curved parts. With the new development of machine tool complex technology, on the basis of CNC lathes, turning and milling centers that can be milled are quickly produced. The processing efficiency of a five-axis linkage CNC machine tool is equivalent to two three-axis machine tools, and sometimes it can even completely save the investment of some large-scale automated production lines, which greatly saves the space and the turnover and transportation time and costs of working between different manufacturing units. . Market demand has promoted the development of my country’s five-axis linkage CNC machine tools. At the CIMT99 exhibition, the domestic five-axis linkage CNC machine tool was on the stage of the machine tool market for the first time. Since Dongguan PTJ Hardware CNC Machining SHOP Co., Ltd. exhibited its first five-axis linkage gantry machining center, companies such as Beijing Institute of Mechanical and Electrical Engineering, Beijing First Machine Tool Plant, Guilin Machine Tool Co., Ltd., Jinan Second Machine Tool Group Co., Ltd. have also developed A five-axis linkage CNC machine tool was developed.
At present, domestic five-axis linkage CNC machine tools have vertical, horizontal, gantry and floor-type machining centers in varieties, which are suitable for processing miscellaneous parts of different sizes, plus five-axis linkage milling machines, large boring and milling machines, and turning and milling. The development of centers, etc. basically covers the needs of the domestic market. In terms of accuracy, the high-precision machining center of Beijing Machine Tool Research Institute, the NJ25HMC40 horizontal machining center of Ningjiang Machinery Group Co., Ltd., and the TH61160 horizontal boring and milling machining center of PTJ Hardware Technology Co., Ltd. all have high accuracy. Comparable with the products of developed countries. In terms of product market sales, the products of PTJ Hardware, Jinan No. 2 Machine Tool, Beijing Institute of Mechanical and Electrical Technology, Ningjiang Machine Tool, Guilin Machine Tool, Beijing No. 1 Machine Tool and other enterprises have gained recognition in the domestic market.
On the morning of July 31, 2013, the high-precision five-axis vertical machine tool manufactured by Dalian Kede was shipped to Germany. Wang Weiming, deputy director of the Equipment Department of the Ministry of Industry and Information Technology, said: “The sale of this high-end CNC machine tool to Western developed countries is an important milestone in China’s machine tool manufacturing industry.”
The Advantage Of 5 Axis Cnc Machine
It is generally believed that the five-axis linkage CNC machine tool system is the only means to solve the processing of impellers, blades, marine propellers, heavy generator rotors, steam turbine rotors, large diesel engine crankshafts, and so on. It is a high-tech, high-precision machine tool specially used for processing complex curved surfaces. The machine tool system has a significant influence on a country’s aviation, aerospace, military, scientific research, precision equipment, high-precision medical equipment and other industries. .
The use of a five-axis linkage machine tool makes it easy to clamp the workpiece. There is no need for special fixtures during processing, which reduces the cost of fixtures, avoids multiple clampings, and improves mold processing accuracy. Using five-axis technology to process molds can reduce the number of fixtures used. In addition, because the five-axis linkage machine tool can save many special tools in processing, the tool cost is reduced. The five-axis linkage machine tool can increase the effective cutting edge length of the tool, reduce the cutting force, increase the service life of the tool, and reduce the cost during processing. The use of five-axis linkage machine tool to process molds can quickly complete mold processing, fast delivery, better guarantee the quality of mold processing, make mold processing easier, and make mold modification easier. In traditional mold processing, a vertical machining center is generally used to complete the milling of the workpiece. With the continuous development of mold manufacturing technology, some of the weaknesses of the vertical machining center itself have become more and more obvious.
Modern mold processing generally uses ball-end milling cutters to process. Ball-end milling cutters bring obvious benefits in mold processing. However, if a vertical machining center is used, the linear velocity of the bottom surface is zero, so the bottom surface finish is very poor. , If you use four-axis or five-axis linkage machine tool processing technology to process molds, the above shortcomings can be overcome.
The Development Trend Of 5 Axis Cnc Machine
- The first is to use linear motor drive technology. After more than ten years of development, linear motor technology has become very mature. Linear motors have just been developed, and the problems of susceptibility to interference and large heat generation have been solved. The positioning technology of linear motors not only stops quickly during high-speed movement, but also some machine tool manufacturers use damping technology to solve them. The advantages of the linear motor are linear drive, no transmission chain, no wear, no backlash, so it can achieve the best positioning accuracy. Linear motors have high dynamics, and the acceleration can exceed 2g. The linear motor drive also has the characteristics of high reliability and maintenance-free.
- The second is the use of dual drive technology. For a wide workbench or a gantry type, if an intermediate drive is used, the actual driving force cannot be guaranteed to be in the center, and it is easy to cause tilt, which makes the dynamic performance poor. Using dual drives, dual grating scales, and one drive module can make the dynamic performance very perfect. One drive command, the two drives work at the same time, and the grating ruler detects whether the two points are balanced, and if they are unbalanced, they can be balanced by different commands. Of course, the development of five-axis linkage machine tool technology is far more than that, and many technologies will be reflected in future machine tool products.