Machining characteristics of micro lens mold in laser-assisted micro-turning

Abstract

Laser-assisted machining (LAM) is a type of hybrid material removal process, which is used for locally and instantaneously decreasing the hardness of materials, such as ceramics and hard composites, by irradiating the material with a focused laser during mechanical cutting. LAM, which has been studied primarily for the macro-machining of the hard materials, was applied to the micro-turning process of high hardness steel for a micro-lens mold in this research. The laser-assisted micro-turning (LAμT) process was analyzed using finite element modeling to predict the thermal effects and temperature distributions induced by irradiation of a focused laser and to determine critical cutting parameters, such as spot size, heading distance, and feeds. The effects of the LAμT were verified by an in-situ comparison with conventional micro-turning method, and the cutting conditions were optimized to maximize the cutting performances in terms of cutting force, surface finish, and chip exhaust. Consequently, a lower cutting force and better surface finish was demonstrated compared to the conventional method for the optimized LAμT condition. Therefore, this study showed that the LAμT can be successfully applied to the micro-machining of hard molds.