Investigation On The Influence Of Laser Texturing On The Anti-stick-slip Behavior Of Guide Surface

Stick-slip phenomenon is a friction phenomenon that occurs alternately between sliding and static contact interfaces under the condition of low-speed driving.Stick-slip phenomenon exists widely in engineering field and nature.However,most of the stick-slip phenomena in mechanical motion are harmful because they destroy the uniformity of motion.It manifests itself as crawling on machine guides,harsh noise on brake disks,and earthquakes in geology.Laser texturing technology is a new surface treatment technology which can form tiny texture on the workpiece surface,thus improving the tribological properties of the surface.The surface texture can improve the friction coefficient,viscosity and wear resistance of the surface,thus improving the anti-stick-slip property of the friction pair surface.Therefore,based on the purpose of improving the anti-stick-slip property of machine guide rail,the theoretical and experimental research on the anti-stick-slip property of laser texture was carried out in an all-round way.The main research contents and conclusions of this paper are as follows.(1)Finite element numerical simulation of anti-stick-slip property of laser textured guide rail.CATIA software was used to establish the three-dimensional models of spherical coronal guide,concave top spherical coronal guide and crater texture guide.The dynamic numerical simulation was carried out by introducing Ansys Workbench software,and the change curves of friction stress,amplitude and equivalent stress over time of the three types of guides were compared.The results show that,compared with spherical coronal texture and crater texture,the concave spherical coronal texture has the smoothest friction stress curve,the smallest amplitude and the smallest equivalent stress,so it has the best anti-stick-slip and anti-fatigue properties.This is related to the phenomenon of stress concentration during movement.Then,different geometric parameters were selected for 3D modeling and dynamic numerical simulation.The effects of different height,diameter and density of the concave top spherical coronal texture on the slip-slip resistance of the guide were compared and analyzed.The results showed that the concave top spherical coronal texture with a height of 7μm,a diameter of 85μm and a density of 13% had the best stick-slip resistance.This is related to the actual contact area,the number of secondary plateaus,the curvature ratio and the initial contact Angle.(2)Experimental study on laser texture technology.The surface of 45 steel was treated by modulated and demodulated 500 W fiber laser.The effects of laser power and pulse width on the texture morphology and geometric parameters of 45 steel were studied.The laser process parameters corresponding to the morphology and geometry of the laser texture were optimized by detecting the morphology and geometry of the laser texture.The results show that with the increase of laser power and pulse width,the laser texture changes from spherical coronal to concave spherical coronal and then to crater shape.The change of texture height with laser process parameters is not obvious.The texture diameter increases first,then decreases and then increases with the increase of laser power,and increases linearly with the increase of laser pulse width.(3)Study on the effect of laser texture on the properties of surface materials.The effect of laser texture on the microstructure and hardness of the specimen surface was studied.The results show that after laser texture,the grain in the melting zone is obviously refined,which is related to the rapid heating and solidification process of the material surface.There is no obvious change of grain in the substrate region.The hardness of the specimen surface also changed significantly.The maximum hardness in the depth direction of the specimen increased by about 9 times,and the maximum hardness in the radial direction increased by about 7 times,which was related to the change of the microstructure of the specimen surface.(4)Experimental study on anti-stick-slip property of textured guide rails.Tribological tests were carried out on the Rtec friction and wear testing machine,and the effects of spherical coronal,concave spherical coronal and crater texture on the stick-slip resistance of the sample surface were studied systematically.The results show that the three laser textures can inhibit stick-slip behavior,and the concave spherical coronal texture can not only reduce the stick-slip amplitude,but also shorten the stick-time,and has the best anti-stick-slip property.In addition,the concave spherical coronal texture first stops the stick-slip behavior and starts to slide stably.The stick-slip amplitude of non-texture,spherical coronal,concave spherical coronal and crater samples were 8.56 N,2.03 N,7.32 N and 16.52 N,and the stick-time were 8.43 s,9.86 s,5.54 s and 5.87 s,respectively.