Effect of cutting speed on the material removal behaviour for sapphire

Abstract

Sapphire optical components are widely used in various industrial sectors. However, they are currently not available through efficient and highly accurate ultra-precision cutting. Therefore, this paper investigates the effect of cutting speed, a key factor in ultra-precision cutting, on the removal behaviour of sapphire materials. The plunge-cuts tests at different cutting speeds (10, 20 and 30 mm/s) have been conducted. The groove surface morphology, critical cutting depth for ductile-brittle transition, cutting force and tool wear of each plunge-cuts test with various cutting speed test were analysed. The experimental results shown that increasing the cutting speed is beneficial to obtain less defective machined surfaces and increase the critical cutting depth for ductile-brittle transition. However, at the same time, the cutting force increases dramatically in the brittle removal mode during high-speed cutting, which leads to severe tool wear. Therefore, increasing the cutting speed to meet the requirements of ultra-precision cutting and machining within the critical cutting depth is a highly efficient measure for obtaining sapphire optical surfaces.