Research On Surface Morphology Modeling In Milling Of Convex Surface Mold

Surface morphology has a serious impact on the corrosion resistance,wear resistance and fatigue resistance of the mold.The research object of this paper is Cr12 MoV mold steel.After quenching,its hardness can reach 50~65HRC.It is a typical hard to machine material.If we only rely on the experimental method to study the surface morphology,not only the experimental process is complicated,but also the cost is very high.With the development of computer simulation technology,if the surface topography and roughness can be predicted by cutting conditions,it will be of great significance to improve the surface quality of the machined mold.Based on the above problems,this paper focuses on the surface morphology of mold steel milling.The main research contents are as follows:Firstly,the prediction model of surface topography in milling of convex surface mold steel is established.The mathematical model of ball-end milling cutter is established,and the influence of tool wear on the mathematical model of ball-end milling cutter is considered.Mathematical model of surface workpiece is established,and the surface workpiece model is discretized into point clouds.Based on the surface characteristics of surface workpiece,the trajectory equation of ball-end milling cutter relative to workpiece is deduced by using vector operation rule and coordinate transformation principle,and the influence of vibration and tool deformation on tool trajectory is considered during the movement of ball-end milling cutter.The simulation algorithm of surface topography is established,and the prediction of milling surface topography is realized.Secondly,the simulation results of the surface topography under different feed,different cutting width,different position of the surface,different tool wear and dynamic characteristics of cutting are obtained by using the simulation model.Milling experiments were carried out,and the variation of surface topography and roughness with cutting conditions was analyzed.The accuracy of the simulationmodel is verified by comparing the simulation results with the experimental results.The comparison results show that the the model is effective.Thirdly,the surface morphology of convex surface mold milling is analyzed by power spectral density,and the signal composition of surface morphology under different feed speed,cutting width,surface position and tool wear is analyzed.The distribution of frequency signals in surface topography and their proportion in surface topography are presented intuitively.The influence of milling conditions on surface topography is revealed,which provides a theoretical basis for the evaluation of surface topography.Finally,based on the GUI module of MATLAB software,a surface topography simulation system is built.The system simplifies the operation steps in the simulation process and improves the efficiency of surface topography simulation.In this paper,a prediction model of surface morphology in milling hardened steel mold with ball end milling cutter is established,which has important guiding significance for studying the influence of cutting conditions on surface morphology and surface roughness.It provides a theoretical basis for the optimization of cutting parameters in the process of machining.