| Nowadays,industrial products and their components in the fields of aerospace,new energy vehicles,chip manufacturing,high-end medical equipment and other fields have complex curved surfaces.In order to meet the performance requirements,complex curved surface parts are gradually pursuing high precision and high quality.It requires extremely high processing efficiency;at this stage,the high-efficiency,high-quality and low-cost processing of complex curved parts are the direction of ultra-precision machining to break through the shackles of existing technologies,and it is also the focus of research in the field of machinery manufacturing in the world.Based on the shear thickening polishing technology,this paper realizes the polishing of workpieces through the shear thickening characteristics of the nonNewtonian power-law fluid polishing medium induced by periodic vibration.Low-cost machining of complex curved parts.The main work of this paper on the vibration-induced thickening polishing method is as follows:(1)The method of vibration-induced thickening polishing on the surface was proposed,the principle of vibration-induced thickening and polishing was explained,and the influencing factors of vibration-induced thickening polishing were analyzed from the aspects of polishing equipment and polishing medium.Based on the polishing principle,a vibration device was selected,a vibration-induced thickening polishing experimental platform was set up,and a kind of polishing medium with remarkable shear thickening properties was successfully formulated.(2)The simulation analysis of vibration-induced thickening polishing was carried out,and a simulation model was established based on the polishing principle to analyze the maximum pressure inside the polishing medium,the maximum pressure on the surface of the workpiece and movement speed of the workpiece surface under different initial heights,constraint distances and vibration frequencies.Based on the maximum pressure on the workpiece surface and the speed of the workpiece at this time,the effectiveness of the vibration-induced thickening polishing method was analyzed,and the evolution law of the surface quality of the workpiece with the initial height,constraint distance and vibration frequency was obtained.The simulation conclusion was as follows: the lower the initial height,the smaller the restraint distance,and the vibration frequency;the larger the value,the greater the maximum pressure on the surface of the workpiece,and the better the surface quality of the workpiece after polishing.(3)The single-factor polishing experiment was realized,and the effectiveness of the vibration-induced thickening polishing method was verified.And the influence of initial height,constraint distance,vibration frequency and abrasive particle size on the polishing effect of vibration-induced thickening was explored,and typical samples were polished with better process parameters.The polishing experiment verified that the evolution law of the surface quality of the workpiece with the constraint distance and vibration frequency was consistent with the conclusion in the simulation analysis.If the constraint distance was too small,the recovery performance of the polishing medium would be affected,resulting in the evolution law of the surface quality of the workpiece with the constraint distance inconsistent with the simulation analysis.When the abrasive particle size was moderate(60μm),the surface quality of the workpiece was the best,the polishing efficiency was the best,and when the vibration frequency was increased,the surface roughness of different abrasive particle sizes after polishing for 1 hour gradually tended to be consistent,close to 50 nm.The surface roughness of a typical sample after polishing reached 20 nm.(4)The vibration force under different process parameters in the vibration polishing process was measured by the force measuring device,and it was found that the vibration force under different initial heights,restraint distances and vibration frequencies was consistent with the surface quality of the workpiece in the polishing experiment.The restraint distance was at10 mm,the vibration force curve fluctuates greatly,which verified that the recovery performance of the polishing medium would be affected when the confinement distance was too small,resulting in a discrepancy between the evolution law of the surface quality of the workpiece with the confinement distance in the polishing experiment and the simulation analysis,and the magnitude of the vibration force under different particle sizes.The relationship was in line with expectations,which provided a supporting basis for the analysis of the evolution law of workpiece surface quality with abrasive particle size. |
