Research On Tool Path Planning Of Ultrasonic Assisted Magnetic Abrasive Finishing For Integral Impeller Blades

Because the machining quality and machining accuracy of the blade surface in the integral impeller greatly affect the performance parameters of the impeller,it is necessary to finish the blade surface.Ultrasonic assisted magnetic abrasive finishing(UAMAF)is considered to be one of the important technologies to solve this problem,but the research on the calculation of step length and row spacing in machining and the attitude control of magnetic pole is not clear.Therefore,in this paper,aiming at the above problems of finishing,the tool path planning of UAMAF for integral impeller blades is studied.The main research work and conclusions are as follows:(1)Based on the cubic B-spline curve interpolation theory,the separate points of the blade curves were interpolated,and the control points were inversed,so as to establish the shaft disc curve,cover disc curve and neutral surface equation of the blade.The suction and pressure surface equations of the blade were established by offsetting the curve,and the integral impeller modeling was completed in UG.The finishing process of the integral impeller blades was analyzed,and the finishing process planning scheme was formulated,which laid the foundation for the subsequent tool path planning.(2)By analyzing the global interference phenomenon in finishing,the feasible region representation model for magnetic pole finishing was established.A collision detection algorithm based on AABB hierarchical bounding box algorithm and triangle intersection detection algorithm was proposed by analyzing the solving method of feasible region in finishing.Combined with the characteristics of UAMAF,the solving range of feasible region in finishing was formulated.On this basis,the calculation method of discrete reference direction of magnetic pole was introduced,and the solving algorithm of feasible region in finishing was established,and the algorithm was verified from the accuracy of the interference check and the computational efficiency.The results show that the algorithm can quickly and accurately calculate the feasible region in finishing.The computational efficiency of the algorithm is improved by about 44.7 % compared with the calculation of the feasible region in machining in the whole domain of Gaussian sphere.(3)By establishing the step size planning model and the row spacing planning model,the path planning method of UAMAF for integral impeller blades was obtained.The constraint conditions of tool axis vector optimization were analyzed.The geometric constraints and machining efficiency were coupled to obtain the optimal solution,and the tool axis vector optimization model was established.On this basis,the tool path planning model of UAMAF for integral impeller blades was established.The model can complete the calculation of the tool position file by inputting the required data,and the correctness of the tool path planning can be verified by simulation processing.(4)In the MATLAB and C++ development environment,the tool path planning model was used to plan the blade suction surface,and the cutter location file was obtained.In MATLAB,the cutter location file was used for machining simulation,and the correctness of the tool path planning method is verified by comparing the ideal machining error with the actual machining error.In VERICUT,a five-axis A-C double table milling machine was built,and the numerical control code obtained by post-processing of the tool position file was used for simulation processing.The correctness of the tool axis vector optimization method is verified by the absence of global interference.