| With the continuous development of science and technology,the demand for components with high processing accuracy and excellent electromagnetic performance in aerospace,instrumentation,energy and defense industry fields is continuous increasing.Pure iron materials have excellent electromagnetic properties which can well meet the material requirements of such components.However,pure iron materials have the characteristics of low hardness,high plasticity,and poor cutting performance,which affects the processing quality of the workpiece.Therefore,high-precision rotary pure iron components are usually processed by a combination of precision turning and elliptical vibration assisted cutting.Pure iron components in the precision cutting process are prone to cutting deformation and tool wear and other undesirable phenomena,which reduces the surface processing quality of the workpiece and affects the machining accuracy of the workpiece.Cutting force is closely related to cutting deformation,tool wear,and workpiece surface processing quality.Therefore,the accurate prediction of cutting force is great significance for improving the processing quality and production efficiency of pure iron components.In this paper,pure iron material is the main research object.Based on the cutting mechanism and the constitutive relationship of the material,the cutting force prediction models of the precision turning process and the elliptical vibration assisted cutting process are established respectively,and finally the cutting force prediction system is designed.The main research contents are as follows:(1)Based on the cutting mechanism and material constitutive relationship,the orthogonal cutting force prediction model and the oblique cutting force prediction model are established.Firstly,the velocity relationship in the orthogonal cutting process is analyzed,and a solution method of shear flow stress which considers the effects of strain rate strengthening,thermal softening and strain hardening is proposed.After based on the orthogonal cutting force prediction model,an oblique cutting force prediction model which considers the influence of the cutting edge inclination angle is established by the coordinate transformation method.(2)Comprehensively considering the influence of tool nose rounding,material strengthening effect,changing sliding friction coefficient and cutting edge radius,a new analytical prediction model of precision turning force is established.Firstly,a calculation method of shear angle,effective rake angle and friction angle is proposed which considers theinfluence of cutting edge radius and sliding friction coefficient;then a plowing force coefficient model considering the influence of changing friction coefficient is established;then a solution method of shear flow stress considering the effect of material strengthening is proposed;finally,the effectiveness of the model is verified by turning experiments.(3)Based on the cutting mechanism,an elliptical vibration-assisted cutting force prediction model is established.Firstly,the ellipse motion trajectory and chip formation mechanism during the cutting process are analyzed,and a method for solving the instantaneous cutting thickness and instantaneous shear angle of a cutting cycle is proposed;later,the prediction model of shear force and plowing force during the elliptical vibration assisted cutting process is established;Finally,the comparison between the prediction results and the experimental results shows that the model can effectively predict the cutting force during the elliptical vibration assisted cutting process.(4)The cutting force prediction system is designed based on the MATLAB GUI toolbox.The precision turning force prediction model and the elliptical vibration assisted cutting force prediction model are applied to the prediction system.The MATLAB GUI toolbox is used to develop the cutting force prediction system,which realizes the functions of parameter input,data output and precision analysis... |
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