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

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 (LA mu T) 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 LA mu T 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 LA mu T condition. Therefore, this study showed that the LA mu T can be successfully applied to the micro-machining of hard molds.