A 3D FEM-based model of laser heating and machining for selection of process parameters and scanning path in laser-assisted machining of Ti6Al4V

Abstract

An appropriate selection of the laser parameters is critical in realizing the potential of laser-assisted machining (LAM) for hard-to-cut materials. This work presents a 3D FEM-based model of laser heating in laser-assisted machining of Ti6Al4V to select the laser parameters. The model accounts for the effect of the laser-tool gap, laser scanning speed, laser power, and laser path (linear and sinusoidal). The laser heating is modeled using a moving continuous heat source with a Gaussian intensity distribution, implemented in Abaqus/explicitTM with the help of a VDFLUX subroutine. The results suggest that the laser-tool gap plays a significant role in heating the entire cutting region. Regardless of power and scanning speed, the laser-tool gap must be sufficient to allow heating of the cutting region. The laser power should be sufficient to soften the material in the cutting zone, but it can be minimized by choosing an optimal value of the laser-tool gap. Also, sinusoidal laser scanning produced the desired thermal softening effects at lower laser powers than linear laser scanning. Accordingly, similar cutting forces are observed in LAM with sinusoidal laser scanning at only half of the laser power as that of linear laser scanning. However, due to the fluctuations in the cutting force for sinusoidal laser scanning, it can be recommended only for rough cuts in machining. The study demonstrates that through an appropriate selection of the laser parameters, the entire cutting zone can be heated to temperatures between 300-500 oC, desired in the machining of Ti6Al4V.