Study On Milling Mechanism And Process Parameters Optimization Of TC18 Titanium Alloy

TC18 titanium alloy is widely used in aviation,aerospace and other fields because of its excellent comprehensive properties.Compared with other traditional metal materials,TC18 titanium alloy has many problems in the cutting process,such as large cutting force,high cutting temperature,serious tool wear and difficult to control the surface quality.These problems make TC18 titanium alloy show the characteristics of low machining efficiency and difficult to control the machining surface quality.However,in order to ensure the surface quality of TC18 titanium alloy,aviation manufacturing enterprises often choose conservative processing parameters,which can not improve the processing efficiency and reduce the production cost.In order to solve the above problems,it is very important to study the milling mechanism and process parameters optimization of TG18 titanium alloy.Based on the above research problems,the dynamic and static characteristics,milling mechanism,milling parameters,milling temperature,surface quality,tool durability and process para,eter optimization of TC18 titanium alloy are deeply studied by means of experiments,analytical modeling,simulation,theoretical analysis and experiments.In order to construct the constitutive equation of TC18 titanium alloy suitable for high-speed milling.DNS100 electronic universal testing machine and Split Hopkinson Pressure Bar were used.SHPB)has carried on the quasi-static compression experiment and the dynamic characteristic experiment to TC18 titanium alloy respectively,obtained the flow stress-strain curve of TC18 Titanium Alloy under the condition of room temperature quasi-static and different temperature and different strain rate,and constructed the JC constitutive model of TC18 Titanium Alloy under the action of high temperature and impact load.Taking the parameters of the JC constitutive equation model as the initial value,based on the Oxley analytical machining theory,using the down hill simplex method of multivariate functions,combined with the orthogonal cutting experiment and the advantage finite element simulation analysis,the JC model parameters are modified,and the JC constitutive model satisfying the conditions of high-speed milling is obtained,which is used for the subsequent analytical machining modeling and TC18 titanium alloy milling simulation System development provides theoretical model and theoretical basis.Based on the theoretical basis of Oxley analytical machining prediction,the JC constitutive equation meeting the conditions of high-speed milling is adopted,the material characteristics of workpiece,geometric parameters of cutter and cutting conditions are considered,and the simulation modules of TC18 titanium alloy orthogonal cutting and oblique cutting are developed by using Lab VIEW software,which can predict the machining processes such as stress,strain,strain rate,cutting force and cutting temperature variable.On the basis of Oxley analytical machining prediction theory,the analytical modeling of milling process and the development of milling process simulation module of cylindrical spiral vertical milling cutter,spherical head spiral vertical milling cutter and circular machine clamping round cutter are studied respectively.The simulation module of milling process of the three cutters can provide theoretical guidance for the selection and optimization of cutting parameters of TC18 titanium alloy materials.The milling force simulation system developed by us is used to simulate and calculate the milling way,and the results are compared with the actual cutting process.The results show that the simulation results are basically consistent with the experimental results.The milling force simulation system can provide some reference for the actual milling process.In order to study the influence of four milling elements on the surface quality,a prediction model of cutting force,cutting temperature and surface roughness is established through orthogonal cutting experiments.The influence of four milling elements on cutting force,cutting temperature and surface roughness is studied from two aspects of experiment and theory.In view of the problem of tool wear in the milling process of TC18 titanium alloy,a tool durability model is established,and the influence of four cutting parameters,namely milling speed Vc,feed per tooth fz,milling depth ap and milling width ae,on the tool durability is analyzed.Furthermore,the wear and durability of the cutting tools sold in the market are compared and analyzed to provide the basis for enterprises to select the cutting tools.Based on the study of milling mechanism and simulation machining of TC18 titanium alloy,combined with the cutting parameters such as spindle speed n,feed per tooth,radial cutting depth ap,axial cutting depth a.,etc.,taking the maximum material removal rate as the optimization objective,the landing gear rocker arm and anti twist arm are selected as the research object,taking the machining surface quality within the machining process requirements and tool life within the allowable range into full consideration The combination of cutting parameters with maximum material removal rate can be used to guide the milling of TC18 titanium alloy.