Research On Testing Method And Testing System Of Precision Spindle Radial Rotation Error

Spindle radial rotation error is an important index to measure and evaluate the working performance and accuracy of the spindle.The spindle error detection can predict and control the quality of the workpiece processed by high-end equipment which depends on the spindle.How to detect and isolate the high precision spindle radial rotation error is a research hotspot.Domestic and foreign scholars have studied and proposed error detection methods such as reverse method,multi-step method and multi-point method.However,due to the influence of uncertain factors such as sensor installation and positioning angle,index and secondary positioning accuracy,the error detection and separation accuracy is not high.In view of the above difficulties,this paper proposes an in-situ error detection and separation method for high-precision error detection of precision spindle.This method combines the testing characteristics of reverse method and three-point method,and improves on the basis of reverse method to avoid the system deviation caused by secondary positioning.Three sensors are used to collect the measurement data at a specific angle.By analyzing the phase difference data collected by different position sensors,the roundness error of the workpiece is separated from the radial error of the spindle.Compared with the traditional three-point method,the error separation process is more concise.The error data acquisition and processing system is developed based on the programming software.Finally,a set of highprecision spindle error detection system is designed and built.Through the experimental study,the effectiveness of the separation algorithm is verified,and the measurement uncertainty of the detection system is evaluated.The main contents of this paper are as follows:(1)An error acquisition method and strategy for precision spindle is proposed.The relationship between the radial rotation error of spindle and the roundness error of standard workpiece and other interference errors is analyzed.A three-point error separation algorithm with specific angle is proposed,and the theoretical formula of the proposed separation algorithm is derived.The simulation results show that the method can separate the random and periodic spindle error from the roundness error,and the separation result is good.(2)The centering problem between the sensor and the detection reference plane is analyzed,and the installation and positioning fixture of the sensor is designed.The installation eccentricity of standard workpiece and spindle is analyzed,and the installation eccentricity adjustment mechanism of standard workpiece is designed.Based on the programming software,the function modules of error data acquisition,data processing and error result display are developed.Finally,a set of high-precision spindle radial error detection system is designed and built based on the hydrostatic spindle.(3)The resolution of the capacitance sensor under the actual working condition is calibrated.With the increase of rotation speed,the synchronous error of the spindle gradually increases,and the asynchronous error of the spindle gradually decreases.By comparing and analyzing the results of 10 times error detection of the spindle at the same speed,the measurement uncertainty error of the experimental system is evaluated.The deviation between the roundness error and the nominal roundness of the standard ball is compared and analyzed,and the effectiveness of the separation algorithm is verified.(4)The harmonic analysis method is used to study the influence of workpiece installation eccentricity error on spindle radial rotation error,and its theoretical model is established.The correlation between the axial error and radial error of the spindle is studied.The experimental results show that the axial displacement of the spindle will lead to the error data collected by the sensor into the system deviation.The experimental results show that the measurement uncertainty of the spindle error detection system is in the nanometer level accuracy,and the separated standard ball roundness error is very close to the nominal roundness error,which verifies the effectiveness of the test method.Through the above research,a set of theories and methods suitable for high-precision radial error detection and separation of precision spindle are obtained,which provides design theory and engineering development basis for the research and development of intelligent spindle and other high-end equipment relying on precision spindle.