• • CaF2 exhibits a Young's modulus of 110.04 GPa, Poisson's ratio <1/3, and hardness of 5.71 GPa, with elastic anisotropy factors between 0 and 1, confirming soft-brittle behavior that causes brittle fracture during conventional cutting; this necessitates auxiliary strategies to maintain ductile-mode removal for optical surface integrity.
• • Fly-cutting achieves a radius error of (0.23±0.04)% and profile error RMS of (208.2±5.76) nm, whereas ultrasonic elliptical vibration cutting (EVC) yields an average profile RMS of 405.56 nm and radius error of 4.56%, with EVC introducing scratches and bottom defects; fly-cutting is thus superior for stable profile accuracy and low roughness in CMLA fabrication.
• • Tool geometric errors are directly replicated onto the workpiece, dominating profile error; after correcting the non-circular-arc tool profile, workpiece profile error RMS dropped from 200 nm to 16.8 nm, demonstrating that tool contour accuracy is the primary lever for achieving sub-20 nm form accuracy in microlens arrays.
• • Tool wear is concentrated at the tip due to long cutting strokes, while middle sections wear less, driven by repeated edge cutting and localized thermo-mechanical friction; this wear progression shifts profile accuracy from a geometry-dominated to a wear-dominated regime, requiring tool life management for sustained precision.