Numerical Modeling And Experimental Study On Deformation Of Thin-walled Parts In Flank Milling

Thin-walled workpiece is widely used in automobile manufacturing,aerospace and other fields.Especially in the aerospace field,there is a strict requirement for the machining accuracy of the thin-walled parts,because thin-walled workpiece has the features of high material removal rate and poor structural rigidity,it is easily deformed when milling,which makes the machining of thin-walled workpiece becomes an difficult problem.In order to decrease the machining error caused by deformation,this thesis will study the regularities and control approaches of thin-walled side milling deformation,explore the efficient manufacturing method of high precision thin-walled workpiece to lay the foundation for the production and application.Milling force and milling heat are the main factors affecting milling deformation of thin-walled workpiece,for these two main influencing factors,a milling force model is proposed on the basic of unit milling force coefficient model by analyzing the advantages and disadvantages of several classical milling force theoretical models and considering thin-walled workpiece side milling processing characteristics.Analyzing the change rule of instantaneous chip thickness in milling process,establishing the temperature predicted model based on Jeager orthogonal cutting mobile heat source model and simulating the change process of milling temperature field by using Matlab.The milling force,the milling heat,the reference point deformation and the surface error under different milling parameters were measured by the orthogonal milling experiment,the correlation coefficients in the milling force and the milling thermal model are calculated from the experimental data,the theoretical value and the experimental value were compared and analyzed,the validity of the theoretical model is verified.Analyzing the internal relationship between the milling parameters and the milling deformation,finally,the favorable combination of milling parameters is obtained.By using the parametric programming of ANSYS,a dynamic simulation program of thin-walled workpiece side milling,which includes geometric modeling,tool cutting and material removal,is compiled,and an analysis model of side milling deformation is established.The finite element analysis model of the thin-walled workpiece side-milling deformation is established by reasonable assumptions and simplification,comparing the deformation rules of the thin-walled workpiece under the load of milling force and thermo-mechanical coupling,the simulation value is compared with the experimental value,the validity of the numerical simulation is verified.The deformation prediction model and the milling parameters optimization model based on BP neural network are established by using the simulation data.Writing the program that predicting the deformation of thin-walled workpiece side milling by using matlab,establishing the milling parameters optimization model by using the simulation data and the deformation prediction model,the milling parameters are optimized,the optimization of the model is verified by the experimental results.