Study on photocatalysis/vibration-assisted finishing for deterministic polishing

Reaction-sintered silicon carbide (RS-SiC) is a promising material for optical systems like space telescopes due to its superior mechanical and thermal properties. However, its multiphase composition, high hardness, and chemical inertness pose significant challenges for conventional polishing techniques in achieving both low form error and surface roughness while maintaining processing efficiency. Photocatalytic/vibration-assisted finishing is a high-efficiency and high-precision polishing process for RS-SiC. After studying the influencing factors and stability of the tool influence function, this study extends the photocatalytic/vibration-assisted finishing to deterministic polishing. The matrix method utilizing the Lucy-Richardson algorithm was employed to obtain dwell time distribution efficiently. The fluctuating concentric circular tool path is developed to avoid periodic residues, interpolation errors, and frequent "swerves". Based on the above innovations, RS-SiC workpieces are deterministically polished to achieve Gaussian hollow topography with a roughness of 0.33 nm in Ra, 0.42 nm in RMS, and a form error of ±30 nm in PV. This study provides a novel approach to the deterministic polishing of RS-SiC. • The stability of TIFs was confirmed during the photocatalysis/vibration-assisted finishing. • The matrix method based on the Lucy-Richardson algorithm efficiently was developed to obtain dwell time distribution. • A fluctuating concentric circular tool path minimized periodic residues, interpolation errors, and frequent swerves. • RS-SiC with a roughness of 0.33 nm in Ra and profile error of ±30 nm in PV was produced after deterministic polishing.