Research On Frank Milling Deformation Of Integral Impeller

The integral impeller is a typical curved thin-walled part,which is widely used in aerospace,marine engineering,chemical industry and other engineering fields.The manufacturing level of impeller greatly affects the reliability of equipment.The integral impeller is usually milled by five-axis CNC machine tool.Because of the milling force,the thin-walled blade is deformed,and the machining error is caused.In this thesis,based on the five-axis milling technology,the milling force of taper ball milling cutter is simulated and predicted.The influence of milling force on blade machining deformation was studied,and the machining error was calculated to modify the milling tool path to improve the machining surface accuracy of thin-walled blade.Firstly,the geometric modeling of impeller is completed,and the generation algorithm of flank milling cutter path is studied.Based on NURBS technology,the digital geometry model of impeller is completed.For the integral impeller,the five axis NC machining process planning is completed,and the process parameter setting,fixture design,milling cutter selection and other works are carried out.Based on the theory of least square method,the algorithm of generating side milling cutter path of ruled surface is realized.Compared with the algorithm of two-point offset method,the design error is greatly reduced.According to DMU-70V five axis CNC machine tool,the program of tool path post-processing is developed.Through VERICUT software,the virtual simulation platform of DMU-70V machine tool is developed,which can monitor the cutter-worker interference in the whole impeller milling and ensure the accuracy of NC code.Secondly,the milling force modeling of taper ball milling cutter is completed.In this thesis,the geometric structure of the cutting tool is studied,and the mechanical prediction model is built by the micro milling force theory.Design experiment to solve milling force coefficient,and the accuracy of the mechanical model is verified by the experimental analysis,which lays the mechanical foundation for the research of the blade milling deformation.Thirdly,the milling deformation of thin-walled blade is studied.Based on the life and death node method in ABAQUS software,the deformation of tool workpiece system is calculated,and the influence of different process parameters(ap,ae,n,fz)on the deformation is analyzed to optimize the process parameters.The off-line error compensation technology is used to correct the tool path.Finally,the five-axis milling experiment of blade is carried out.The influence of process parameters on the surface morphology was analyzed by orthogonal test.The results showed that the influence of axial cutting depth ap and spindle speed n on the surface morphology accounted for a large proportion.The design of five-axis machining development platform for integral impeller integrates the functions of geometric modeling,side milling cutter path planning,milling force prediction,machining deformation simulation,etc.,which greatly reduces the manual operation and intervention,and has certain application value for the production and manufacturing of integral impeller.