Research On Deformation And Compensation For Turning Of Aero-engine Thin-walled Casing Parts

In the field of aero-engine manufacturing,turning is a commonly used method for thin-walled ring parts,especially in the processing of thin-walled casing parts.Because of the low stiffness of aero-engine thin-walled casing,the deformation caused by the cutting force and other factors has a great influence on the machining accuracy,trial period and trial cost of the parts.So in this dissertation,the finite element method is used to study on the turning process of aero-engine difficult machining material thin wall cylinder(casing),the error compensation based on deformation of the workpiece.The main contents of this dissertation are as follows:Through the construction of the three-dimensional turning simulation model of aero-engine thin-walled casing,the changes of the machined surface and the temperature of the cutting depth in the cutting process with the cutting speed and the casing wall thickness are studied.For the very thin part,the method of the internal and external casing surface spray the emulsion is put forward to reduce the influence of cutting heat on the deformation of parts.In view of the problem of the deformation error caused by cutting force in cylindrical turning of aero-engine thin-walled casing parts,using finite element method to forecast casing cylindrical turning deformation(cutter),and gets the change law between the deformation and the cutting depth;then it utilizes the curve fitting method to derive the depth correction function,which is employed for tracking the tool locus after compensation to control the deformation of machining.Aiming at the problem of deformation caused by cutting force of aero-engine thin-walled casing tongue piece,the simulation analysis is carried out.Based on the analysis of the geometric characteristics of tongue piece and the prediction model of cutting force,the finite element method is used to predict the volume of flame tube tongue piece deformation(relieving amount),applies the curve fitting to get the tool compensation trajectory curve,then makes this curve to carry on the error compensation of the tool locus trajectory,and ultimately achieves the purpose of reducing processing deformation.The error compensation method proposed in this dissertation can effectively solve the problem of machining error caused by the force induced deformation in the machining of cylindrical turning of aero-engine thin-walled casing parts and tongue piece,and improving the machining accuracy,shorten the development cycle and reduce the production cost.The method can provide useful reference for other similar product deformation prediction and error compensation.