Research On The Tool Path Planning For The Blade Finish Machining Of The Open-type Integral Blisk With Barrel Cutter

This article is oriented to the five-axis CNC machining of the integral blisk.To solve the following problems as the low efficiency of point milling with ball-end tools,the blade surface is usually a non-expandable ruled surface,the applicability of side milling with tools such as tapered cutters is not high,and the existed tool path planning algorithm of the barrel cutter is not well-targeted,the tool path planning algorithm for the blade finish machining of the open-type integral blisk with barrel cutter is studied.Three main research objects involved in the blade finish machining with barrel cutter are analyzed: the kinematics of the five-axis CNC(Computer Numerical Control)machine,the structure of the open-type integral blisk,geometric characteristics of the barrel cutter,and key coordinate system.In order to ensure the integrity of the root fillet,the blade surface is divided into a non-root area that does not interfere with the root fillet,and the root fillet boundary area processed from the upper boundary of the root fillet to the tip of the blade.Based on the principle of minimum cutting overlap between rows,a dynamic toolpath planning algorithm with variable line spacing is proposed for sub-regions.Aiming at the processing of the upper boundary of the blade root fillet,the cutter contact point is solved under the premise of ensuring that the large arc of the barrel cutter passes through the upper boundary of the blade root fillet.In the design of advance and retreat tool,a solution algorithm for the advance and retreat points located at the front and rear edges and the semicircular arc advance and retreat lines of the tool path in the layer is proposed.In terms of local interference solution,the minimum distance between discrete points and the blade surface is calculated based on the meshing method,and the spherical projection method is used to determine the parameter domain for the analysis of the convexity of the blade surface.Given that the blade is in the convex part,it is not necessary to mesh.Accelerated local interference detection.Based on the three-dimensional space separation axis theory and the space line-surface intersection method,the detection process of global interference is solved.A search algorithm that does not interfere with the tool axis is given,and the causes of the continuous parameter domain and the discrete parameter domain are determined.In the calculation and optimization of the tool axis,the optimization criteria based on the relative change of the pitch and inclination of the drum knife attitude and the angle of the machine tool AC axis were determined.Based on the Ultra CAM platform,the finishing strategy of the drum blade blade is realized,and the calculation model is given.Through the analysis of the planned tool path,it is verified that the drum cutter is more efficient than other tools,the solved tool path is smooth,and the machine axis runs smoothly.Finally,VERICUT software was used to simulate the generated tool path to ensure the processing safety.The Hermle C42 U fiveaxis machine tool was used for workpiece trial cutting,and the three-coordinate measuring instrument was used to evaluate the quality of the processed blades,which verified the correctness of the algorithm.The research results are helpful to the application of the drum knife in the finishing of the integral blisk blade,and it has good economic benefits.