Concept of a viscoelastic polishing tool based on shear-stiffening effect for aspheric surfaces figuring

Aspherical optical components are widely used in aerospace, optics, and healthcare due to their unique geometry, driving growing demand. Traditional small-tool polishing for the aspherical components suffers from low error convergence efficiency due to mechanical interference and poor tool compliance, especially in high-curvature areas. In this paper, a spherical shear-stiffening gadget polishing (SSGP) tool is proposed to adapt to surface topography via dynamic fluid-solid transition under shear loading. In fixed-point polishing experiments, teardrop-shaped removal functions were obtained, whose contour and distribution are significantly influenced by the tool rotation speed and load. Additionally, fixed-point polishing experiments on deep-cavity components confirmed that the proposed tool exhibits significantly reduced sensitivity to curvature radius variations. Figuring experiments achieved rapid error convergence from RMS 0.4λ to 0.1λ in two iterations, which verified the adaptability and effectiveness of the SSGP tool for ultra-precision polishing and shows the potential application in aspherical optical components figuring.