Some researchers have suggested that a reasonable balance of the quality of the tool can be determined in the following way: for rough machining with a large amount of metal removal (such as the machining of aluminum alloy parts of the aircraft, the cavity of a large mold, the machining of aluminum alloy shells, etc.) It is sufficient to balance the quality level up to G16, but when the power consumption of this rough machining is large, G6.3～G8.0 can be used in the range of 15000～24000r/min to reduce the unbalanced force to the spindle bearing. Additional load. For finishing, the tool system must have a balanced mass rating of at least G6.3. It is also not excluded to adopt a higher balance quality level (even smaller than the lower limit of the FKM specification), which requires online balancing of the tool system and the spindle as a whole after the spindle is loaded. Previous page Floor Heating Solid,Modern Minimalist Floor,Light Luxury Style Floor,Solid Wood Flooring TECLIC , https://www.teclicfloors.com
At present, the new HSK63 overall structure tool holder with hydraulic expansion clamps from Schunk has a factory balance quality of G6.3, and the residual unbalance is 4gmm. The recommended speed is 15000r/min. The company's finely adjustable and balanced hydraulic expansion clamps can be used up to 50,000 rpm.
5. Tool online balance system
When the user uses the tool at the machining site, due to the combination of the tool system and the coupling of the tool holder and the spindle, a certain amount of eccentricity may be generated, so that the pre-balanced tool generates a new imbalance, so The on-line balancing system that balances the entire tool-toolholder-spindle system in the driven state is extremely practical, and it is even possible to directly use the unpre-balanced tool assembly for machining.
The structure and working principle of the online balance system developed by Baladyne Company of the United States is as follows: the system consists of sensors, controllers, counterweight disks, coils, and the like. There are two electromagnetically driven counterweight discs on the main shaft. By adjusting the position of the two counterweight discs, the unbalanced force generated and the unbalanced amount of the tool system to be balanced can be offset each other to achieve the purpose of online balance. After 2.5 seconds of "learning", the system integrates the balance function in the spindle to collect the dynamic characteristics of the entire system, and then after 1 second of automatic adjustment, the balance can be achieved. The system is currently available for speeds of up to 60,000 rpm. According to Baladyne, a pre-designed counterweight is sufficient to achieve complete online balancing with unpre-balanced tools.
The online balancing system developed by Kennametal of the United States consists of a balanced tool holder, an accelerometer, a controller and a regulator. The feature is that the electromagnetically driven weight plate is placed in the holder to automatically adjust the relative position of the holder weight plate. The system balances the spindle and tool system as a whole without having to use a special spindle.
6. Conclusion
At present, high-speed rotary tools have been promoted and applied in some industrial sectors in China. The research and development of high-speed cutting technology has become an urgent task facing China's manufacturing industry, especially the machine tool industry. At the 7th Beijing International Machine Tool Exhibition in 2001, China's existing machine tool manufacturers exhibited machine tools with spindle speeds of 10,000 to 15,000 r/min. The tool industry also had the ability to develop high-speed cutting tools through technical transformation. This has created the necessary conditions for the promotion and application of high-speed cutting technology in China. The tool dynamic balancing technology matched with high-speed cutting technology has become a common technical subject of the machine tool industry. Accelerating the research and development of this technology will contribute to the development and application of high-speed cutting technology.