Insights into hydrodynamic self-balancing mechanics in adaptive float machining process for nanometric form error control

Abstract

With advances in semiconductor and aerospace industries, the demand for components with atomic and close-to-atomic scale accuracy is paramount. As a non-contact method, float machining is showing great potential for excellent surface finishing, where the adaptive fluid film between the tool and workpiece plays an essential role. However, its dynamic self-balancing mechanics remains unexplored, without revealing which, the outcome of extreme accuracy could be hardly touched or controlled. To address this issue, a hydrodynamic coupling dataset driven hydrodynamic model with in-situ force-position sensing approach is proposed. This work presents the first systematic elucidation of the transient processes governing the fluid film-tool interaction as the system achieves a balancing state. Simulation and experiments were conducted to demonstrate the adaptive film evolution route, and its relation to the specific process conditions with precise prediction. Insights into the intermediate states and inherent self-balancing mechanism enable exceptional form control ability, namely deterministic removal of 3 nm in depth across an arbitrary 3 mm region. Subsequently, a sinusoidal hyperbolic freeform with form error within ±2 nm PV over a 5 mm region was fabricated using only a stepper-motor platform, and the underlying process produces an atomically ordered, damage-free subsurface. Furthermore, the capability for non-uniform machining was verified by fabricating compound-eye structures and correcting curved surfaces to nanometric form accuracy.