Research On Dynamic Error Measurement System Of Multi-axis CNC Machining Center Based On R-test

Five-axis CNC machine tools are now more prevalent due to the manufacturing industry’s growing demands for the geometry and precision of manufactured products because of their superior performance in the field of surface machining,but their structure and control system are more complex than three-axis CNC machine tools,making it more difficult to test the error and improve the accuracy.The use of conventional error measurement equipment such as dual-frequency laser interferometer,ball bar,etc.can be very good to achieve the static error measurement of machine tools,but for the dynamic error measurement of five-axis CNC machine tools with the addition of rotary axes,there is a single detection,testing process is time-consuming and difficult to ensure the accuracy of measurement and other shortcomings.Therefore this paper is based on R-test measuring instrument designed a set of non-contact dynamic error measurement of machine tools system based on R-test measuring instrument,the primary effort in this article is as follows::1.The basic structure of the non-contact R-test measuring instrument is analyzed,and two structural parameters that need to be optimized in the system design are determined.On this basis,a structural parameter optimization method based on the actual measurement state of the sensor is proposed.The two indications of the system measurement space volume and the measurement range are taken into account by the procedure.By tweaking the associated indicators,the displacement sensor’s ideal installation angle and position can be found.2.A non-contact R-test measurement system based on the actual measurement state of eddy current displacement sensor measuring ball center spatial coordinates calculation method is proposed.The approach relies on the eddy current displacement sensor along the sensitive direction and perpendicular to the sensitive direction displacement measurement data change law,through the target position at the target position of the ball center in the measurement range of each sensor can be moved in the region of the intersection of the intersection point to reflect By adding the correction matrix M,the influence of the processing and installation errors of the sensor and its probe fixture on the measurement results is eliminated,so that the system ensures the accuracy of the calculation results while ensuring the rapidity of the solution process.Aiming at the problem that the measurement coordinate system and the machine coordinate system are not parallel,the conversion algorithm between the measurement results in the two coordinate systems is studied,and the two commonly used coordinate conversion algorithm models of Bursa and Molodensky are analyzed and compared.3.The eddy current displacement sensor and other related equipment are calibrated.Through the comprehensive analysis of the experimental data,the displacement measurement characteristic equation of the sensor in the actual state is obtained.On this basis,the parameter optimization calculation and shape design of the system structure are carried out.Based on the analysis of the basic functions of the system measurement software,combined with the actual work situation and operation convenience of the measurement system,a modular measurement software is developed.4.Considering the research of this paper,the dynamic error measurement system of multi-axis CNC machining center is built,and its measurement accuracy is verified experimentally on the KMC600 S U-type five-axis CNC machining center,and the results show that the non-contact R-test measurement system designed in this paper has an accuracy of ±3μm,which meets the actual measurement requirements,and then verifies the validity and efficacy of the optimization design method suggested in this paper.