Experimental Study on Cluster Magnetorheological Variable Gap Dynamic Pressure Planarization Finishing

Abstract

：In order to improve the effect of cluster magnetorheological planarization finishing of photoelectric wafer, a method of cluster magnetorheological variable gap dynamic pressure planarization finishing is proposed, and the influence of various process parameters on the polishing effect is explored. Using the sapphire wafer as the research object, a comparative experiment of cluster magnetorheological variable gap dynamic pressure planarization finishing and cluster magnetorheological finishing is carried out. The surface roughness and material removal rate of the finishing surface is detected, the finishing surface morphology and the morphological changes of the magnetic chain string in the cluster magnetorheological polishing pad before and after dynamic squeeze is observed, the influence of squeeze parameters such as squeeze amplitude, workpiece disk rotation speed, squeeze frequency and minimum machining gap on the machining effect is studied. The experiment shows that after the cluster magnetorheological planarization finishing applies the axial low-frequency vibration of the workpiece, the magnetic chain string formed in the cluster magnetorheological polishing pad is thicker, which not only makes the magnetorheological polishing fluid flow along the radial direction of the workpiece to realize the dynamic update of the abrasive particles, promoting the increase of the number of effective abrasive particles in the finishing interface, but also the dynamic polishing pressure is generated in the machining gap between workpiece and polishing disk, and make the abrasive and surface scratching process soft and micro-quantified, which forms a mechanism to improve the removal efficiency of the material and reduce the roughness of the processed surface. Compared with the effect of cluster magnetorheological finishing, the cluster magnetorheological variable gap dynamic pressure planarization finishing has a material removal rate increased by 19.5%, the surface roughness is reduced by 42.96%. Finishing under the process parameters of squeeze vibration frequency 1 Hz, minimum machining gap 1 mm, squeeze amplitude 0.5 mm, workpiece disk rotation speed 500 r/min can obtain an ultra-smooth surface with a surface roughness of Ra 0.45 nm, material removal rate reached 3.28 nm/min. It is