Research On Cutting Force And Thermal Characteristics In High-speed Turning Ti6Al4V

For the superior properties of high strength-to-weight ratio, good hot strength,high corrosion resistance and excellent low temperature performance, titaniumalloys have been used widely in aeroengine manufacture and aerospace industry,weapons manufacture, medical and chemical fields in recent years. The weightof the plane is reduced and the overall structure efficiency is improved ofthe aircraft by using titanium alloy, which have the broad scientific researchspace and application prospect.However, titanium alloys are regarded asdifficult-to-cut materials because of their low deformation coefficient, lowthermal conductivity, and high chemical reaction, which lead to the unit cuttingforce large, the cutting temperature high and the tool wear serious, whichlimits the development of the titanium alloy material high-speed cuttingtechnology.With its high efficiency, high precision, high surface quality andother advantages, high speed machining technology has become the mainstreamprocessing technology of titanium alloy thin-walled components in large aircraftmanufacturing enterprises, which has showed vigorous vitality. Therefore, thepresent study aims at analyzing cutting force and thermal characteristics inhigh-speed turning titanium alloy Ti6Al4V, and then providing theoretical basisfor optimization of cutting parameters and tool parameters, evaluating cuttingperformance and optimization design of tool edge, which can promote thedevelopment and application of titanium alloy high-speed turning technology.The main study contents and fruits are listed as follows：First, a high-speed cutting titanium alloy cutting process simulationmodel was built to study the forming process of serrated chip in high-speedcutting titanium alloy, combined with high-speed cutting titanium alloyexperiments and the introduction of dislocation motion and shear slip.Metallographic microscope and scanning electron microscope (SEM) were used to observe the microstructure of the chip to analyse effect of cuttingconditions to the formation of the scraps and the reasons of serratedformation, which is the foundation of cutting force and thermalcharacteristic research of high-speed turning titanium alloy.Second, the orthogonal cutting model incorporating tool edge (round edge)was established in high-speed turning Ti6Al4V in the light of classical cuttingmodel. The finite element simulation model of high-speed cutting Ti6Al4V wasbuilt to study the characteristic of cutting force incorporating cutting parameter,tool parameter and cutting edge, which provide theoretical support foroptimization of tool parameters, cutting parameters and optimization design oftool edge to evaluate cutting performance.Third, according to the researches of thermal generation and thermalconductivity, the temperature distribution and the effects of cutting conditions onthe thermal features and temperature variation in cutting Ti6Al4V process wasstudied using FEM.Finally，the experiments of high-speed turning Ti6Al4V were taken to verifythe validity of the finite element simulation model on the basis of the studies.Finite element analysis of cutting force and cutting temperature values are ingood agreement with experimental results, high-speed turning process of titaniumcan be well simulated by the established finite element simulation model.