Anti-wear Mechanism And Cutting Performance Of Single Crystal Diamond Tool With Micro/nano Texture Processed By Femtosecond Laser

Single crystal diamond is extremely hard and can be machined with extremely sharp cutting edges.It is the most commonly used tool material for ultra-precision turning,but single crystal diamond turning tools are expensive,the sharpening process is complicated,and the resharpening cycle is long and costly..Studies in the field of tribology have confirmed that micro-textured surfaces can significantly improve the rubbing characteristics between friction pairs,and have been successfully applied to improve the life of cemented carbide tools and ceramic tools,but there is no research and research on single crystal diamond tools,application.Due to its extremely high peak energy and "cold processing" characteristics,femtosecond lasers show unique advantages in surface texture processing,but studies on the mechanism and influence of femtosecond laser processing of single crystal diamond have rarely been reported.This study proposes the application of femtosecond laser micro-nano processing technology to the micro-nano texture processing of single crystal diamond surface,and applies the micro-texture to the anti-friction effect of the tool to the single crystal diamond ultra-precision turning tool.The research content and results of this thesis have important theoretical significance and practical value for revealing the femtosecond laser processing mechanism of single crystal diamond,improving the life of single crystal diamond tool and improving the precision and efficiency of superfinishing.In this paper,the influence of process parameters on the macroscopic size and microstructure of single crystal diamond processed by femtosecond laser is studied.In the interaction with the femtosecond laser,the single crystal diamond has a Gaussian distribution of laser spot energy,and a hot-melt damage region is formed at the center of the spot,and a non-hot-melt damage region is formed at the outer edge of the spot.Since the(110)crystal plane atomic density of the single crystal diamond is larger than the(100)plane,the ablation threshold of the(110)plane is larger.In order to obtain a high surface quality microstructure,the laser power should be controlled to less than 8.5 mW during processing.Increasing the scanning speed can improve the processing efficiency,but the groove depth and the groove width of the groove are reduced,and the high-quality high aspect ratio microstructure can be obtained by repeating the scanning multiple times.Further optimizing the processing parameters,using the parameter combination of P=0.4mW and v=50um/s,four kinds of micro-nano textures were fabricated on the single crystal diamond sheet and the cutting environment was simulated.The fretting wear experiment was carried out and several textures were measured.The surface friction coefficient shows that the friction reduction effect of the micro-texture under dry friction is not obvious,and even the friction coefficient is increased to some extent.Under the lubrication condition,the friction coefficient is significantly lower than that of dry friction,and the surface texture is also more effective.The friction coefficient of the longitudinal groove texture is about 23%lower than that of the smooth surface.Finally,according to the results of the test cutting experiment,five different micro-nano textures were processed in the main wear area of the rake face of the single crystal diamond tool and the cutting comparison test was carried out.The results show that in addition to the concentric circular texture,the depth of cut resistance and the coefficient of friction of the rake face of the other four textures are greatly reduced.The single?crystal diamond tool with surface micro-nano texture has a significant reduction in the wear area and wear depth of the rake face,and the wear area is away from the cutting edge,ensuring the strength of the cutting edge.