Hemispherical resonator with low subsurface damage machined by small ball-end fine diamond grinding wheel: A novel grinding technique

As for the ultra-precision grinding of the hemispherical fused silica resonator, due to the hard and brittle nature of fused silica, subsurface damage (SSD) is easily generated, which enormously influences the performance of such components. Hence, ultra-precision grinding experiments are carried out to investigate the surface/subsurface quality of the hemispherical resonator machined by the small ball-end fine diamond grinding wheel. The influence of grinding parameters on the surface roughness (SR) and SSD depth of fused silica samples is then analyzed. The experimental results indicate that the SR and SSD depth decreased with the increase of grinding speed and the decrease of feed rate and grinding depth. In addition, based on the material strain rate and the maximum undeformed chip thickness, the effect of grinding parameters on the subsurface damage mechanism of fused silica samples is analyzed. Furthermore, a multi-step ultra-precision grinding technique of the hemispherical resonator is proposed based on the interaction influence between grinding depth and feed rate. Finally, the hemispherical resonator is processed by the proposed grinding technique, and the SR is improved from 454.328 nm to 110.449 nm while the SSD depth is reduced by 94 % from 40 μm to 2.379 μm. The multi-step grinding technique proposed in this paper can guide the fabrication of the hemispherical resonator.