Study On Surface Texture Evluation And Variation Rule Of Five-axis Ball End Milling Under The Change Of Tool Posture

In five-axis ball-end milling,geometric error compensation is often used to improve the accuracy of machine tools.However,in the process of geometric error compensation,the abnormal sudden changes of tool attitude angle will cause unpredictable surface defects.Based on the analysis of current situation at home and abroad in five-axis ball-end milling surface texture simulation and experiment,surface topography evaluation and prediction,and geometric error compensation,this paper carries out the evaluation of the surface topography under the change of tool attitude angle.First,this paper establishes the kinematics trajectory equation of the ball-end milling cutter in five-axis milling,performs surface simulation modeling on the workpiece,and obtains the corresponding surface topography.Based on the existing evaluation of the surface topography quality indicators,the surface micro-element of the workpiece and the overall morphology is analyzed.At the micro-element level,surface texture quality evaluation indicators such as the largest micro-element volume and the largest micro-element area are proposed to describe the surface texture micro elements;the overall contour curve and volume matrix are used to describe the surface contour changes of the workpiece at different positions on the overall level of the workpiece.At the same time,Euclidean distance is used to describe the similarity of contour curves under different conditions.Secondly,establish the simulation model of the plane workpiece under different tool attitude angle combinations and extract the surface topography.Use the surface topography quality indicator,the surface texture quality indicator and the surface texture trend to describe and simply divide the workpiece surface,and then use the clustering algorithm to obtain the range of the tool attitude angle under the restricted surface texture.On the basis of simulation,select other tool attitude angle combinations and tool types in different classifications to conduct experiments to verify the simulation model and tool attitude angle range division,and believe that the tool attitude angle range division is only suitable for ball-end milling,other milling cutter processing can not use the clustering results.Then,select multiple locations on the hemispherical surface and the entire surface to simulate the surface topography,extract the surface topography quality and texture quality indicators for the surface topography of different positions in dequence,classify the tool attitude angles simply,and then use the clustering algorithm to classify the different positions.The surface morphology is divided into ranges,which proves that the results of different positions of the workpiece are completely consistent.On this basis,the overall simulation and cluster analysis of the workpiece are performed,and the results are completely consistent with the results of the division of a single position.It is proved that the surface texture simulation result of a part of the workpiece can be used to represent the overall result of the workpiece.Finally,the Euclidean distance is used to describe the similarity of the contour curves of the workpiece feed direction under different simulation conditions.Finally,the effects of spindle speed,feed per tooth,cutting depth and cutting line distance on the surface topography and surface texture quality under different combinations of tool attitude angles are studied.The results show that when the tool attitude angle is changed,the influence of different parameters on the surface topography quality and texture quality indicators does not change.The feed per tooth and the cutting line distance have a greater impact on the maximum micro-element volume and the maximum contour height.Other parameters have little effect on the surface texture.Therefore,in the geometric error compensation and actual machining,in addition to the tool attitude angle,the influence of the feed per tooth and the cutting line distance on the surface topography of the workpiece can also be considered.