Key Technologies for High Speed CNC Machining Cutting Development

- Mar 28, 2019-

With the development of high-speed CNC machining cutting, ultra-high-speed CNC machining cutting technology and CNC machining cutting tools, more and more mechanical manufacturing equipment is constantly shifting to high speed, high precision, high efficiency and high intelligence. The demand for high-speed CNC machine tools is increasing. In the design and manufacture of high-speed CNC machine tools, high-speed CNC numerical control electromechanical spindles are the most critical.


At present, foreign companies engaged in the development and production of high-speed CNC machine tools CNC numerical control electromechanical spindles mainly include German GMN, Siemens, Swiss IBAG, American Setco, Italian Omlet, Faemat, Gamfior and Japanese giant cockroaches, among which GMN, IBAG, Omlet, Setco and Gammfier The company's technology represents the highest level in this field.


The CNC mechanical and electrical spindles produced by these companies have the following characteristics compared with domestic production: high power and high speed; high-speed, high-rigidity bearings, high-speed, high-rigidity bearings on high-speed precision spindles, mainly ceramic bearings and liquids. Dynamic and hydrostatic bearings, air-lubricated bearings and magnetic suspension bearings for special occasions; high level of precision machining and precision assembly; high level of supporting control systems, including rotor automatic balancing system, bearing oil and gas lubrication and precision control system, stator cooling temperature Precision control system and spindle deformation temperature compensation precision control system. On this basis, these foreign manufacturers such as the United States, Japan, Germany, Italy and Switzerland have produced a variety of commercial high-speed machine tools.


Development trend of CNC numerical control electromechanical spindle technology

A

Continue to develop toward high speed and high stiffness

Due to the needs of high-speed CNC machining and practical applications, with the development of spindle bearings and their lubrication technology, precision machining technology, precision dynamic balancing technology, high-speed tools and their interface technology, CNC CNC electromechanical spindles for CNC machine tools It has become a common trend in current development, such as CNC mechanical and electrical spindle for drilling and milling. The speed of HF42 of Swiss IBAG reaches 140 000 r/min, and the CNC mechanical and electrical spindle D1733 of PCB drilling machine of British WestWind has reached 250. 000 r / min; machining center with CNC numerical control electromechanical spindle, Switzerland FISCHER maximum speed reached 42 000 r / min, Italy CAMFIOR reached 75 000 r / min. In terms of the system stiffness of CNC numerical control electromechanical spindles, due to the development of bearings and their lubrication technology, the system rigidity of CNC numerical control electromechanical spindles is getting larger and larger, which meets the needs of high-speed, high-efficiency and precision machining development of CNC machine tools.


B

Development towards high speed, high power, low speed and high torque

According to the needs of actual use, most CNC machine tools need to meet the requirements of heavy CNC machining and high-speed CNC machining during low-speed roughing. Therefore, the machine tool CNC numerical control electromechanical spindle should have low speed, high torque and high speed and high power performance. For example, CNC CNC electromechanical spindles are used in machining centers produced by manufacturers such as CAMFIOR in Italy, Step-Tec in Switzerland and GMN in Germany. It is not difficult to output torque to 200 N·m in low speed section. CNC milling machine and lathe CNC CNC of Germany CYTEC The maximum torque of the electromechanical spindle is up to 630 N·m; in the high-speed section, the power is generally 10 to 50 kW; the maximum output power of the CYTECCNC CNC electromechanical spindle is 50 kW; the maximum of the Swiss Step-TecCNC CNC electromechanical spindle The power is 65 kW (S1) for aircraft manufacturing and mold processing; more reports of CNC electromechanical spindle power of 80 kW.


C

Further development towards high precision, high reliability and extended working life

Users have put forward higher and higher requirements for the accuracy and reliability of CNC machine tools. As one of the core functional components of CNC machine tools, CNC numerical control electromechanical spindles require higher precision and reliability. For example, the radial runout of the main shaft is within 0.001 mm and the axial positioning accuracy is below 0.5 μm. At the same time, due to the use of special precision spindle bearings, advanced lubrication methods and special preload application methods, the life of CNC numerical control electromechanical spindles has been extended accordingly, and its reliability is getting higher and higher. Step-Tec's CNC numerical control electromechanical spindle is also equipped with an acceleration sensor to reduce the vibration acceleration level of the bearing. In order to monitor and limit the vibration on the bearing, a vibration monitoring module is installed to extend the working life of the CNC numerical control electromechanical spindle.

D

CNC CNC electromechanical spindle built-in motor performance and form diversification

In order to meet the needs of practical applications, the performance of CNC numerical control electromechanical spindle motor has been improved. For example, the ratio of constant torque high speed and constant power high speed (ie constant power speed regulation range) of Swiss FISCHER spindle motor output reaches 1:14. . In addition, the permanent magnet synchronous motor CNC numerical control electromechanical spindle appears. Compared with the CNC electric and mechanical spindle of the same power asynchronous motor, the synchronous motor CNC numerical control electromechanical spindle has a small outer shape, which is beneficial to increase the power density and realize small size and high power.


E

Fast start, stop response speed

In order to shorten the auxiliary time and improve the efficiency, it is required that the start and stop time of the CNC machined CNC spindle of the CNC machine tool is as short as possible, so a high start and stop plus (minus) speed is required. At present, the acceleration and start-up acceleration of the CNC machined electromechanical spindle of foreign machine tools can reach more than lg, and the full-speed start-stop time is less than l s.


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