| With the rapid development of aerospace and automotive moulds and other fields,the requirements of the mechanical manufacturing industry for machined surfaces are no longer limited to high precision and high quality,and the preparation of functional surfaces has gradually become the focus of the demand.The body surface morphology of many organisms in nature has a good effect of drag reduction,which provides a good guidance for the preparation of functional surfaces.If the bionic non-smooth surface with drag reduction effect can be directly prepared by high-speed milling,it plays a significant role and important practical significance in prolonging the service life of parts,reducing energy consumption and saving production cost.For this reason,this paper is supported by the National Nature Fund project"Design,characterization and precise Manufacturing of Wear-resistant functional Surface under the condition of High Speed Milling(Project Code: 51775151).Through the analysis and demonstration of the feasibility of realizing bionic bionics of typical biological surface topography in high-speed milling,an ellipsoidal head milling cutter suitable for machining surfaces with drag reduction characteristics is developed,and the secondary finishing milling method of ellipsoidal head milling cutter is put forward.The milling surface topography model is established,and the drag reduction characteristics of the surface topography after secondary milling are obtained.The main research contents are as follows:First of all,a variety of biological surfaces with good drag reduction characteristics are analyzed,the structural characteristics of their body surface morphologies are summarized,and the drag reduction mechanism of different biological surface morphologies under lubrication is explored.Secondly,in order to meet the preparation of bionic non-smooth surface topography,an ellipsoidal head integral milling cutter suitable for machining small curvature surfaces is developed,and three kinds of cutting edge models are put forward according to geometry and the design principle of ellipsoidal head milling cutters.compared with the ball-end milling cutter,its advantages in cutting performance are analyzed.at the same time,combined with the topography characteristics of the machined surface under the condition of high-speed milling,the method of secondary finish milling is put forward.The feasibility of realizing bionic morphology by high-speed milling is demonstrated.Thirdly,the formation mechanism of surface residual topography in high-speed milling of ellipsoidal end milling cutter is analyzed by using the method of theoretical analysis.The coordinate system of machine tool,workpiece and tool is established,and the coordinates of any point on the cutting edge of ellipsoidal end milling cutter in static state are obtained.According to the principle of kinematics,the motion trajectory equation of any point on the cutting edge is solved when the ellipsoidal end milling cutter is in secondary milling inclined plane and cutting parameters are changed,and the model of surface morphology under secondary milling is established.At the same time,the simulated point cloud data are obtained,and the surface reconstruction method is used to synthesize the corresponding free-form surface to realize the visual expression of surface topography.Finally,through the design of high-speed secondary milling experiments of Cr12 Mo V hardened die steel with different parameters,the accuracy of the surface topography model is verified,and the effects of processing parameters on the shape and size of micro-pits are analyzed.The friction force and friction coefficient of bionic non-smooth surface under alternating load were measured and calculated by using friction and wear tester,and the drag reduction effect of bionic non-smooth surface under surface contact lubrication was analyzed.The drag reduction characteristics of different biomimetic surfaces under the condition of high-speed secondary milling were obtained. |
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