Coupling Analysis And Control Of Machining Interference And Deformation Of Five-axis Machining Of Centrifugal Impeller

Centrifugal impeller is the core component of the aircraft engine.The machining quality of impeller directly influences its service life and mechanical properties.Due to the complexity of the blade surface,in the process of centrifugal impellers,the cutting tools will produce some problems,such as interference,collision and so on.The problems will cause some adverse consequence such as geometric programming error,part deformation error.Therefore,how to establish a reasonable tool path without interference and less error,and to ensure the accuracy of five-axis NC machining and reduce the machining error is the key part to realize the high efficiency and high precision machining of the five-axis NC machining of centrifugal impellers.For this reason,the paper takes the influence of tool interference and machining deformation on the error in five-axis NC machining into account.The multi-axis NC machining theory,tool envelope surface theory,error compensation principle,numerical simulation technology and other technical methods were comprehensively used to explore the distribution law of blade deformation error and tool motion interference error.The specific research work is as follows:1)The establishment of 3D model of impeller and the research on the planning of tool path were carried out.The NURBS fitting data points was used to build the complex non-developable ruled surface blade,and the parametric modeling of centrifugal impeller was carried out by UG.Combined with the geometry of the impeller and five-axis side milling processing technology,planning a reasonable collision-free processing area,and the initial blade axis vector of the cone cutter was calculated by the offset method.Finally the reasonable tool path was obtained.2)The Study on machining deformation of five-axis side milling of impeller blade was implemented.This paper studies the motion mechanism of five-axis CNC machine,and the control process of machine tool axis was analyzed.Based on the principle of single parameter variable radius family of spheres,and the vector algorithm was used to derive the enveloping surface of the cutter.Finally,the error value between the envelope surface of the cutter and the theoretical surface was calculated.3)The study on the deformation of five-axis side milling of impeller blade wasimplemented.Based on the empirical prediction model of milling force which has been established by our research group.AdvantEdge PM was utilized to verify the milling force.The milling force was imported into the ANSYS platform,and the deformation distribution of impeller blade during the milling process was studied.4)The coupling analysis and simulation verification of machining interference error and machining deformation were carried out.On the basis of 3),Using the least square method to establish deformation compensation surface,and according to the tool envelope theory,the tool envelope surface was established for the compensation surface.The distribution of error value between the envelope surface and the theoretical surface was analyzed.The optimization algorithm of multi axis cutter location was used to reduce the machining error,then optimized tool path was established.The post processing algorithm was deduced for the five-axis NC machine tool C30,and the NC program which could be identified by the machine tool was built.The simulation of the milling was performed in the VERICUT software to verify the correctness of tool path and post processing algorithm.The machining error of the blade was measured by three coordinate measuring instrument.In conclusion,the research of this paper provides an effective solution to reduce the five-axis NC milling error of impeller blades,and laid a theoretical foundation for optimizing and improving the five-axis NC machining process of centrifugal impeller.