Milling Tests To Measure Five-axis Machine Tool Errors

With the rapid development of modern manufacturing industry,five-axis CNC machine tools have been widely used in many fields.The error of five-axis CNC machine tool directly affects the machining accuracy.Therefore,how to measure various errors existing in the machining process and compensate them to improve the machining accuracy is one of the key technologies in the machine tool industry.This paper proposes research on machining error modeling,tool error measurement and machine tool geometric error measurement.Using these methods,machine tool geometric error of each axis and tool rotation errors can be measured through milling test.This paper proposes the research background and significance of five-axis machine tool error measurement.The chapter summarizes the common methods of measuring machine tool space motion errors,the development of machine tool error cutting test methods and tool rotation measuring methods.In the aspect of machining error modeling,the influence of the tool rotation error on the movement of the flat-bottom milling cutter is analyzed.Based on the analysis,the motion equation of the cutting edge is established.Combining the cutting edge motion equation with the traditional cutting force calculation equation,The cutting force model of the flat-bottom milling cutter under the influence of the tool rotation error is established and verified by an experiment.Then the tool rotation error,deformation error and the traditional machine tool geometric error model were combined to establish a comprehensive machining error model.The model was validated by workpiece error prediction experiment.In the aspect of tool rotation error measurement,two methods,namely,surface frequency feature method and surface texture method,are proposed to reverse the tool turning error based on the machined surface topography.The former method calculates the surface energy at different cutting heights according to the surface height data,and compares the measured energy value with the simulated energy value to calculate tool rotation error.The latter method calculate tool rotation error value according to the surface texture features.In the aspect of machine tool geometric error measurement,the actual machine geometric error equation under various machining conditions is analyzed.A new method to measure each axis'geometric errors of a dual-rotary table five-axis machine tool based on the feature of the workpiece's position errors was proposed.A test piece was machined according to the design of the Haas mini-mill machine.The error prediction and the compensation experiment of the workpiece validated the method.