Balancing surface quality and machining efficiency in fused-silica hemispherical resonator via combined magnetorheological polishing and chemical etching

Subsurface damage introduced by grinding significantly affects the energy-dissipation behaviour of fused-silica hemispherical resonator (HSR). Magnetorheological polishing and chemical etching are considered effective techniques for removing subsurface damage in fused silica HSR. However, the simultaneous achievement of high removal efficiency and superior surface quality remains a challenge. This work focuses on energy-dissipation mechanisms and subsurface-damage removal strategy for HSR. Firstly, the reaction behaviours of fused silica components that exhibit different surface qualities during chemical etching are analysed. Based on the reactivities of the different surface types with the chemical etchant, the processed areas are categorized into seven distinct reaction zones, revealing the directional nature of the chemical reaction with the surface materials. Secondly, the evolution of the surface morphologies of HSRs exhibiting different surface qualities under chemical etching is investigated. Higher initial surface roughness is found to produce greater variations and longer stabilization during etching. Further analysis demonstrates that the surface morphology and the form and distribution of subsurface damage significantly influence the energy-dissipation of HSR. Finally, a processing strategy for effectively improving the quality factor of HSRs is proposed, based on the correlation between surface quality and performance under various processing parameters. The proposed strategy reduces the fabrication time from 28 to 10.5 h, and improves the quality factor from 2.05 × 10⁷to 2.26 × 10⁷, achieving simultaneous enhancement of both efficiency and performance. This research advances the understanding of the energy-dissipation mechanisms in HSR and provides practical guidance for the high-efficiency and high-performance manufacturing of HSR.