Research On Tool Path Planning Of Cavity High Speed Milling Based On Constant Radial Engagement Angle

With the emergence of high-end CNC machine tools,advanced cutting tools,and the rapid development of CNC machining technology,high-speed cutting has the advantages of small cutting force,low cutting temperature,small processing deformation and high production efficiency,and its engineering applications are becoming more and more extensive.As a typical high-speed cutting processing method,cavity milling can remove all materials in any closed boundary on the workpiece plane to a fixed depth,and is suitable for processing planes,grooves,various forming surfaces and complex profiles of molds,etc.Therefore,it is widely used in aviation,aerospace,automobile,mold and other industries.The machining efficiency and machining quality of cavity milling largely depend on the results of tool path planning.This paper takes cavity high-speed CNC milling as the research object,and proposes a new tool path planning method.The method first determines the cutting depth of each layer according to the allowable machining deformation;then determines the radial engagement angle of each layer according to the stable cutting conditions.Tool path planning is based on constant radial meshing angle;finally,the tool paths generated at each layer are unified into a complete path to achieve constant cutting force and high-efficiency precision milling without chatter.First,build a cutting dynamics model for cavity milling to realize three-dimensional dynamic cutting force prediction;then analyze the stability of the milling process,and use the zero-order analytical method to solve the model to obtain the stability lobe diagram;based on the graphics of the classic milling stability domain Above,the milling stability lobe diagram under the fixed axial depth of cut is constructed,which lays the foundation for the subsequent constant radial depth of cut milling.Secondly,based on the geometric description of the cavity milling processing boundary,the real cutting parameters such as the feed per tooth,the undeformed cutting thickness,the cut-in and cut-out angle,etc.during the cavity milling process are theoretically analyzed and corrected,and the curvature of the processing path is analyzed and corrected.The mutation site was analyzed in detail,and some related parameters were adjusted.On this basis,a new tool path generation algorithm for high-speed CNC milling of cavities based on constant radial meshing angle is proposed.Finally,four examples are given to show the feasibility and advantages of the tool path generation algorithm for constant radial meshing angle.Finally,it focuses on the realization of the tool path generation algorithm for cavity milling based on constant radial meshing angle.The layer cutting method is used to obtain the milling contour boundary of the cavity,and the contour boundary is discretized into a series of straight line and circular arc segments according to a predetermined accuracy.Find the intersection,remove the interference ring formed by adjacent offset segments,retain the effective offset ring,and generate a feasible tool offset path.The characteristics and deficiencies of the two modes of normal transition and arc transition between rings are analyzed,and on this basis,a spiral path connection method is proposed.Finally,through simulation examples and trial cutting,the feasibility and effectiveness of the tool path generation method and algorithm for constant radial meshing angle proposed in this paper are verified.