Research Of The High-precision Dynamic Balancing Technology For Spindle Of Ultra-precision Machine Tool

Currently, ultra-precision machining has a wide range of applications in many different fields, while it also promote the development of machinery, molds, optics, sensors and measuring technology etc., which plays an important role in the development of national defense and cutting-edge technologies. The spindle is one of the most critical components of all rotation ultra-precision machine tools, and its performance have a crucial impact on all of the whole machine’s precision, reliability etc. The center of mass of the ultra-precision machine tool’s spindle inevitably is inconsistent with its center of rotation due to the uneven of material, errors of the assembly in the manufacturing and assembly process. Even the high-precision manufactural and well-balanced spindle will also generate new imbalance mass because of workpiece clamping, uneven load etc. while in the process. To ensure the quality of ultra-precision machining, we must use the onsite balancing instrument to adjust the mass distribution after the workpiece clamping and before the process. This method of adjustment is not only inefficient, but also can’t guarantee its stability. Therefore, adjusted the mass distribution and monitoring the vibration of the spindle while the ultra-precision machine tool is working has become a key technology. In addition, although the balancing state of the spindle is better than the highest standards of ISO 1940, but it still has impact on the process, so this paper try to evaluate the balancing state of the spindle from the perspective of the surface quality.In order to balance the flotation spindle system of the ultra-precision machine tool on-site efficient and precise, to solve the problem about dynamic unbalance, vibration and the evaluating of dynamic balancing state, this paper analyzes the relevant theoretical knowledge, including extraction of unbalance vibration signal, calculation of the unbalance magnitude and phase, developing the spindle balancing test system, designing the field balancing adjust device, analysis of experimental results and errors, evaluation of the balancing result related to the surface quality of the workpiece.Firstly, build the field detection system of the spindle balancer. By using the vibration sensor, data acquisition card and other hardware, combined with self-made software and the dynamic balance theory, we measure and extract the signal of the vibration of the spindle, and calculate the magnitude and phase of the unbalance quality. Meanwhile, do some tests and analyze the errors, so to test the practicability of this system.Then, in order to reduce the vibration of the spindle, we design and produce the field balancing equipment due to the structural characteristics of the flotation spindle, and combined with the balancing algorithm and self-writing software, adjusted the mass distribution of the spindle. Next, integrated the algorithm into the machine control system to achieve balancing operation without weight test, and monitor the balancing state of the spindle in real-time.Finally, do some balancing test and analyze its effects on the surface quality of the workpiece, and then evaluate its allowable amount of unbalance mass and vibration combined with the surface quality of workpiece.