Geometric Error Modeling And Precision Design For Five-Axis CNC Gear Forming Grinding Machine

High-precision CNC machine tools are the basic manufacturing equipment at the national"made in China 2025" strategic level,and accuracy distribution is a priority in the design of machine tool reverse precision.Taking the five-axis CNC gear grinding machine as an example,this paper aims to improve the geometric precision of the machine tool space,constructs the spatial geometric model of the tool and workpiece based on the standard homogeneous coordinate transformation,multi-body system theory and other methods,and simplifies using the small error hypothesis model.Finally,the whole geometric error model of the CNC machine tool is obtained.According to the machine tool geometric error model and the direct matrix differential method,the sensitivity of each single item geometric error of the CNC machine tool is calculated,and the accuracy of the machine tool is assigned based on this.Using laser interferometer to complete part of the geometric error Item measurement,geometric error compensation by modifying the numerical control code.The main tasks of this article are:In view of the spatial structure characteristics of CNC machine tools,this chapter is based on the multi-body system theory and thestandard homogeneousofcoordinates principle.After using the small error assumption model simplifies.a general mathematical model for the spatial geometric error of CNC machine tools is finally established;andtaking a 5-axis CNC gear grinding machine as an example for modeling application.Taking a five-axis CNC gear grinding machine as the experimental object,the positioning errors and straightness errors associated with the X-axis,Y-axis and Z-axis were measured using the RENISHAW laser interferometer,and the X-axis roll angle error was analytically calculated;Y-axis and Z-axis positioning error as an example to compensate,experiment results show that NC code can effectively reduce the CNC machine tool geometric error peak,but also can do furtheroptimization andcompensation.The direct differential method was used to derive the sensitivity analysis model of CNC machine tools,and the geometrical error sensitivity coefficients were calculated and normalized.The main error items affecting the spatial geometrical error of CNC machine tools were obtained,which was used as a basis to study the precision design of CNC machine tools.Based on the geometric error modeling and sensitivity analysis method of the whole machine,the MATLAB GUI was used to complete the machine tool accuracy analysis expert system software.The software can realize the automatic calculation of all three-axis CNC machine tools and most common five-axis CNC machine tool geometric error model and error analysis.