| Titanium alloy is widely used in the manufacture of fasteners in the aerospace field due to its low density,high strength,good corrosion resistance,and high heat resistance.The manufacturing process of fasteners is melting,forging,rolling,surface finishing,flaw detection,lubricant application,and finally delivered to the processing plant for processing and manufacturing.The surface finishing process is an important part of the raw material processing of fasteners,which requires the use of centerless lathes for surface removal turning.During the machining process,improper selection of process parameters can lead to high cutting forces,high residual stress,chip accumulation,poor surface quality and other problems.Finite element analysis of titanium alloy turning is performed by using ABAQUS software to set different process parameters to establish a simulation model.The data of cutting force,residual stress and chip shape are extracted from the model,and the test platform is set up for different working conditions for turning test.The simulation and test data are compared and analyzed to verify the reliability of the model.The effects of lathe spindle speed,feed rate and depth of cut on cutting force,chip shape and residual stress were studied in depth.The preferential study of titanium alloy turning process parameters was carried out to improve the machining efficiency.The main work of this paper is as follows:(1)A three-dimensional finite element model of centerless lathe for finishing turning was established based on the elastic-plastic theory of finite elements using the finite element analysis software ABAQUS.The key techniques of the modeling process are studied: the division of the mesh,the setting of the intrinsic constitutive equations and material property parameters,and the selection of the fracture criterion and separation criterion.The chip morphology and cutting force under different process parameters are obtained by the simulation model,and the test platform of centerless lathe is built to calculate the cutting force and collect the chips under different working conditions,and the simulation and test data are compared.The analysis shows that the model simulation results are consistent with the test,and the preferential selection of process parameters of machining process is carried out.(2)Surface residual stresses under different working conditions were extracted in the simulation model.An experimental platform for measuring residual stresses by Xray diffraction was built.The simulated and experimental data of residual stresses under different working conditions were obtained and compared and analyzed respectively.The influence of different process parameters on the surface residual stresses was studied,and the accuracy of the simulation model was verified.(3)The grid node displacements of the machined surface were extracted in the simulation model,and the tool tip vibration displacements were obtained and calculated using accelerometers in the centerless lathe test rig,and the two displacements were coupled to obtain the simulated roughness.The roughness of the machined titanium alloy is measured,and the simulated and experimental roughness are compared and analyzed.The effect of different process parameters on the surface roughness is investigated. |
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