Numerical modelling and simulation studies of laser beam heating parameters on depth of cut and surface temperature in laser-assisted machining of Ti6Al4V

Abstract

Laser-assisted machining (LAM) is a hybrid machining process which uses a laser heat source to heat the narrow zone of a work part material ahead of the cutting tool. Surface temperature and heat-affected depth (effective depth of cut) achieved during localised laser heating play an important role in the machinability of the workpiece. In the current work, moving laser heat source simulation studies are performed using COMSOL Multiphysics software. The effect of laser power, beam diameter, scan speed, convective heat transfer coefficient and absorptivity are studied by simulating different test cases. Results show that the average maximum surface temperature increases when the laser power is increased from 100 W to 160 W by 55%. It increases with the increase in absorptivity from 0.3 to 0.39 by 18%. The average maximum surface temperature decreases when the laser diameter is increased from 1 to 2.5 mm by 46%. It decreases with the increase in scan speed from 50 to 200 mm/min by 5%. In the case of effective depth of cut, similar trends were observed with the variation of the above parameters. Further, the variation of convective heat transfer coefficient from 5 to 20 W/m-K does not affect the average maximum surface temperature and effective depth of cut. It was found that the laser power has a significant effect on average maximum surface temperature and effective depth of cut compared to other parameters.