Abstract: Magnetorheological variable gap dynamic pressure polishing uses the axial low-frequency vibration of the workpiece to produce the extrusion strengthening effect of magnetorheological fluid, which can effectively improve the processing effect and make the photoelectric wafer quickly obtain nano surface roughness. The influence of different variable gap parameters on polishing pressure in magnetorheological variable gap dynamic pressure polishing process is studied by rotating dynamometer test. The results show that the polishing pressure changes periodically under the axial low-frequency vibration of the workpiece; The axial low-frequency vibration process of the workpiece can be divided into pressing process and pulling process. The pressing speed and the pulling speed have different response characteristics to the dynamic polishing force. The polishing pressure increases sharply with the decrease of the minimum machining clearance. When the minimum clearance residence time was set to observe the change of polishing pressure, it was found that the polishing force gradually weakened from the peak value and stabilized during the minimum clearance residence. The vibration amplitude has little effect on the pressure of polishing. A material removal model is established for magnetorheological variable gap dynamic pressure polishing, and the mechanism of abrasive regeneration and additional movement under the action of dynamic pressure was clarified. The mechanism of flexible scratching and micro removal of abrasive particles on workpiece surface during magnetorheological gap dynamic pressure polishing is studied, which provides a theoretical basis for the process optimization of magnetorheological variable gap dynamic pressure polishing.

Key words: photoelectric chip, magnetorheological polishing, variable gap dynamic pressure, polishing force, flattening