Study On The High Speed Spindle Online Dynamic Balance Vibration Signal And Optimization Of Dynamic Balance Regulating Strategy

CNC machine tools play a very important role in modern precision processing,and are an indispensable part of the national industrial system.The vibration of spindle greatly affects machining accuracy of CNC machine tools,and the geometric error of machining will be affected when the vibration is severe.The application of on-line dynamic balance technology can restrain the unbalance of the spindle and reduce the vibration.On-line dynamic balance can monitor real-time vibration of the spindle and restrain the vibration.It is a fast,efficient and accurate balancing method.It plays an important role in reducing the vibration of the spindle and improving the machining accuracy.In this thesis,the built-in electromagnetic sliding ring and motor-driven mechanical dynamic balancing device are taken as the research objects.The extraction of vibration signal of spindle and the optimization of quality compensation strategy are.studied.The main contents of this thesis are as follows:(1)The theory of unbalance of spindle is deeply studied.The dynamic balancing methods and techniques used in dynamic balancing are summarized.The influence coefficient method,built-in electromagnetic sliding ring and built-in mechanical motor driven dynamic balancing device,and the application of virtual instrument in dynamic balancing are studied in detail.The paper classifies the unbalance of spindle,expounds the cause of unbalance,the mechanical model of unbalance and the expression method of unbalance.(2)Setting up the testing system of spindle vibration,using NI company’s software and hardware products.The hardware extracts signal and analog-to-digital conversion,the software filters the signal and processes the fundamental frequency signal,tests the finite impulse response and the infinite impulse response,and compares the fundamental frequency signal extracted by FFT,correlation analysis,mutual power method and all-phase FFT signal processing methods in whole and non-whole periods.Through experimental comparison and analysis,all-phase FFT has the best analysis of phase frequency,and all-phase FFT is chosen as the vibration signal processing method.(3)The quality compensation strategy is optimized in in spindle dynamic balancing.Aiming at the counterweight block in the balancing device,a genetic optimization algorithm is proposed to calculate the phase of counterweight blocks.Four mobile strategies of counterweight blocks are proposed.Comparing their moving time and the impact on the spindle when they move,the fourth mobile strategy has proved to be the best mobile strategy.Based on SYL04H-1 lathe spindle,the non-optimal balance and optimal balance are carried out in electromagnetic slip ring and motor driven mechanical dynamic balance device.The results show that the amplitude of the optimized balance decreases by 36.21%and the equilibrium time decreases by 57.14%compared with that of the unoptimized balance in electromagnetic sliding ring dynamic balancing device.In the motor-driven mechanical dynamic balancing device,the amplitude of optimal balancing is reduced by 45.7%compared with that of non-optimal balancing,and the maximum time of balancing is decreased by 43.86%.The proposed mobile strategy is verified and the efficiency of spindle balancing is improved.