| As an important material in aerospace and other fields,titanium alloy is widely used in various fields.As a difficult material,the surface integrity of titanium alloy has a significant impact on its fatigue properties.Therefore,it is of great significance to obtain better surface integrity of titanium alloy by improving its machinability and optimizing processing parameters.At present,there is no corresponding surface integrity evaluation system to provide reference for production.In this paper,titanium alloy TC4 was selected as the research object,the end milling cutter was used for high-speed milling of the workpiece,the surface roughness,surface residual stress and surface work hardening were selected as indicators,and the surface integrity of titanium alloy was studied.Firstly,single factor test was carried out,and cutting speed,feed per tooth,milling width and milling depth were selected as independent variables.The influence law of each milling parameter on each index of surface integrity was obtained,and its mechanism and principle were analyzed,which provided a basis for the accuracy verification of the subsequent model.Then the orthogonal experiment was carried out,the surface roughness prediction model was established by empirical method,and the multiple linear regression equation was established by matlab fitting.The experimental results in Chapter 2 were substituted to verify the reliability of the empirical model.The finite element prediction model of surface residual stress and surface work hardening was established by using the finite element method and the special cutting simulation software Advant Edge FEM,in which the surface microhardness was represented by the symbolic value,and its validity was verified by the single factor test results.In Chapter 4,the influence degree of each process factor on each index is determined by analyzing the signal-to-noise ratio of each index of surface integrity.Then,Taguchi method is combined with the grey relational degree theory to optimize the multi-objective parameters of each evaluation index of surface integrity,calculate and compare the grey relational degree of each process parameter combination,and obtain the optimal milling process parameters.Compared with the optimal combination in the orthogonal test,it is found that the grey correlation degree is improved.Finally,the surface integrity evaluation system was established based on python language.Through the process parameters defined by users and the automatic operation of the interface through Py Auto GUI function,the simulation data and grey correlation degree of each evaluation index of surface integrity could be output,so as to evaluate the excellent surface integrity and provide some reference for the production practice. |
