Research On Ultra-precision Multi-axis Milling Process And Shape Accuracy Of Complex Surface Parts

With the rapid development of science and technology,micro-mechanical and micro-electromechanical systems are favored by scholars at home and abroad because of their advantages of small space occupation,low energy consumption and material saving.The process technology and manufacturing equipment for high-precision micro parts limit the development of this field.In this paper,the complex surface parts are taken as the research object.Based on the analysis of the original milling process problems,combined with the processing difficulties of the target parts,the part's milling process is deeply studied.The main research work of this paper includes:To solve the problem that the surface of the ultra-precision machining is susceptible to the occurrence of tool marks,the processing route of the target part is formulated on the basis of analyzing the processing difficulties of the target parts.In consideration of the control of the tool axis,the step length,the step distance,and the projection method,the processing module using UG software was used to the machining trajectory planned and the tool radius compensation was performed using the model offset method.In order to realize the conversion of the tool path point to the NC program,the post-processing of the ultra-precision 5-axis machine was developed based on the UG/Post Builder module;Use VERICUT software to simulate the machining process and verify the correctness of the finishing tool path and post-processing software.In order to improve the accuracy of surface shape,the error sources of the ultra-precision five-axis milling process system and the error elements of the main error sources were analyzed.Based on the kinematics theory of the multi-body system,the comprehensive error model of the process system was deduced and the comprehensive error model was used.The influence of main error sources(machine tool error,fixing error,tool setting error)on the accuracy of the surface shape is analyzed.To improve surface quality,the influence of the spindle speed n,the milling distance a_e,the milling depth a_p,the feed speed v_c,and the tool inclination ? of five process parameters on the surface roughness was analyzed based on the orthogonal experiment;the surface roughness was established.The empirical model of surface roughness was established,the F-test was constructed,and the empirical formulas and coefficients were tested for significance;The genetic algorithm is used to optimize the process parameters and optimize the combination for the part processing.Finally,the ultra-precision milling experiments of the parts were carried out to verify the superiority of the ultra-precision multi-axis milling process for complex curved surface parts.The roundness error of one section of the part is detected,and the correlation between the experimental results and the simulation results is verified.The correctness of the shape accuracy prediction method based on the integrated error model is verified;the surface roughness of the five parts of the part is tested and compared before and after optimization.The surface quality of the parts has verified the effectiveness of the roughness optimization results,and the surface roughness has reached the requirements of the technical indicators;in order to clarify the uneven surface roughness of the parts,further discussion of other factors affecting the processing quality.