Fabrication of controllable random micro-structured surface by using FTS-based diamond turning

Random micro-structured surfaces (RSS) have great application potentials as various functional surface elements, such as optical diffusers and hydrophobic/hydrophilic surfaces. Conventional fabrication methods for RSS, such as chemical etching, are no longer suitable for modern requirements of high precision and controllability. In this study, a novel method was proposed for fabricating controllable random dimple arrays by using fast tool servo (FTS)-based single-point diamond turning. Firstly, small patches of quadratic surfaces were periodically arranged over a large surface area. Then the position, height, and size of each quadratic surface were adjusted by applying random values whose dynamic range is preset. In this way, the spatial difference between the dimples were under control within an adjustable range. Finally, the fabricated surface was evaluated to validate the effectiveness of the proposed method. Results showed that the machined surface feature matched precisely with the designed one. This method provides possibility for mass production of high-precision RSS by patterning mold inserts for molding/imprinting processes.