The Detection Method Of Machine Tool Geometric Error Based On Composite Reference

Error detection and compensation technology is an effective means to improve the machining accuracy of the machine.The technology of error detection determines the error identification method.In this paper,a modeling and identification method for the geometric error of a multi-axis CNC machine with C-axis turntable is designed for the detection instrument of the error detection technology based on the composite reference parts.The main work is as follows:1)A division test method is proposed.The detection of rotating axis error and the translation axis error is separated.As an example,the geometry error modeling and identification for multi-axis machine tool and the positioning error detection for turntable is introduced using this method respectively.2)A modeling method for three-axis machine tools is introduced,which involves a modeling general step for machine tools with different structures.This paper also presents a calibration method for the placement error of the reference parts.3)This paper designs an identification method for step error detection method based on composite reference.Considering the advantages and characteristics of the measurement system,the composite reference parts is designed in three-way arrangement and the identification steps are arranged.Using the plane feature of reference to directly detect the angular error,and the parabolic feature to identify linearity error indirectly.Taking the FXYZ type three-axis machine as an example,the computer simulation proves the feasible and accurate of the identification method.Then,Hanchuan XH715 D vertical machining center is modeling using this method.The experimental results show that the identification model can identify the geometric errors.Finally,the factors that affect the recognition accuracy is analyzed combining the optical measurement system.4)A method for detecting the angular error of turntable is designed.The optical measuring head should be placed on the diameter to remove the eccentricity caused by the placing error.The experimental platform is set up to complete the calibration of the optical measuring head and the angle detection experiment.The difference between the measured data and the laser interferometer is 2 ",which proves that the system has good precision and repeatability.The research results of this subject provide a theoretical basis and a practical guide for the application of the new testing equipment in the field of error testing of multiaxis CNC machine tools,which will provide new ideas for machine tool error detection and identification.