Research On Ultrasonic-assisted Magnetorheological Finishing Removal Model And Processing Method Of Fused Silica

Hemispherical Resonator Gyro(HRG)plays an important role in the field of inertial navigation for its excellent performance.As the sensitive element of Hemispherical Resonator Gyro,Hemispherical Shell Resonator(HSR)determines the performance of Hemispherical Resonator Gyro.Hemispherical Shell Resonator is processed from highpurity fused silica.In order to ultimately improve the polishing efficiency and surface quality of the Hemispherical Shell Resonator,the ultrasonic-assisted magnetorheological finishing of the fused silica is studied.In order to meet the polishing requirements for the thickness of the residual defect layer on the polished surface,the mathematical material removal models in ultrasonicassisted magnetorheological finishing when the polishing head is vertical and oblique are established respectively according to the Preston empirical equation,based on the study of the analysis of the ultrasonic stress,the magnetic levitation stress and the hydrodynamic stress on a single polishing particle.The finite element simulation of the ultrasonic-assisted magnetorheological finishing is completed.The effects on the material removal in ultrasonic-assisted magnetorheological finishing by the main processing parameters,such as the speed of polishing head,the ultrasonic vibration amplitude,ultrasonic frequency,the gap between the polishing head and workpiece,the angle of polishing head are studied by finite element simulation.In order to meet the polishing requirements for the surface roughness,the mathematical surface roughness models in ultrasonic-assisted magnetorheological finishing are established,which can be used to solve the descent speed of surface roughness and the ideal final roughness,the polishing time can be estimated,according to the initial roughness and required roughness.The effects on the surface roughness in ultrasonic-assisted magnetorheological finishing by the main processing parameters,such as the speed of polishing head,the ultrasonic vibration amplitude,ultrasonic frequency,the gap between the polishing head and workpiece,the angle of polishing head are studied by finite element simulation.The polishing experiments when the polishing head is vertical are carried out.The polished surface profile of experiments is in good agreement with that of simulation results,and the trend of the maximum removal depth of the material at different polishing gaps is consistent with that of simulation.the validity of the mathematical material removal models is examined by the experimental result,both experimental and simulation results demonstrate that ultrasonic assistance can improve the efficiency of magnetorheological finishing.