Experimental Evaluation of Direct Laser Assisted Turning through a Sapphire Tool

Laser assisted machining (LAM) techniques have been investigated to improve the efficiency and quality of machining operations by thermally softening hard to cut materials. Traditionally, the techniques were applied in such a way that the heating zone was in front of the cutting tool, softening materials prior to chip formation. In order to reduce energy consumption and prevent unwanted phase changes in the materials, we propose a direct laser assisted machining technique where a laser beam is applied through a transparent sapphire tool, directly affecting the tool-workpiece contact surface. The sapphire tool has a high hardness compared to conventional tungsten carbide tools, while its transparency allows for the direct application of the laser through the tool. In this study, we investigated the effects of applying a direct laser assisted machining technique, and we observed changes in cutting behaviors including cutting forces, surface finish, and adhesion. Aluminum and bulk metallic glass workpiece materials were examined to investigate how crystalline and amorphous materials behave under direct laser assisted machining techniques. Experimental results showed that the proposed technique reduced forces and improved surface finish.