Research On Deformation Control Of Impeller Machining Based On Feedrate Optimization

The integral impeller is mainly used in aero engines,the blade is used free-form surface modeling,which is not only large in distortion,but also very thin,so it is mainly processed by a five-axis CNC machining center.This paper analyzes the problems of low dimensional accuracy and poor surface quality caused by the elastic deformation of the blade during the finishing process of the integral impeller,and establishes a finite element model of the impeller surface structure.According to the numerical prediction result of the milling force,the blade processing is predicted Research on the amount of deformation in the process,on the basis of these work,proposed a method to optimize the feed rate with the goal of reducing the cutting force,and secondly,the goal was to minimize the cutting force component in the most flexible direction of the tool contact.The method of optimizing the tool axis vector finally achieves the purpose of controlling the deformation.The specific research content is as follows:(1)In this paper,the research on the finishing process of a certain type of integral impeller is carried out,and the relevant processing scheme is designed,and the numerical control processing simulation is carried out in the VERICUT software.A finite element model of the impeller surface is established,and the corresponding deformation of the finite element model is calculated when each node is subjected to unit loads in three directions.The cutting force coefficient calibration experiment was carried out,and the corresponding cutting force coefficient of the finishing tool was calculated.Then according to the cutting force model,the cutting force at each tool contact is calculated,and then the deformation of each tool contact is calculated.The blade studied in this paper is processed by the traditional machining method of fixed feed rate,and the actual milling force during the machining process is measured at the same time.After the machining is completed,the actual coordinates of the blade marking points are measured by a three-coordinate measuring machine,and the deformation amount of the marking points is calculated.Finally,the actual deformation at the marked point of the blade is compared with the predicted deformation of the predicted milling force and the calculated deformation of the actual milling force,and the error analysis is performed.Based on the deformation of the tool contact point,an optimization method is proposed to reduce the feedrate of the tool at the tool contact with a large deformation,and to increase the feedrate of the tool at the tool contact with a relatively small deformation.Based on the tool contact deformation calculated by the measured milling force,the above optimization method is used to optimize the blade finishing NC code to verify the effectiveness of the method;the predicted milling force is used to calculate the deformation of the tool contact,and the above optimization method is used to The NC code for blade finishing is optimized to verify the prediction and optimization effect.Experiments show that the finishing feed rate optimization method based on the deformation of the tool contact reduces the elastic deformation of the blade by 30-40%during the machining process,and improves the machining accuracy of the blade.