Finite element analysis of evaporative cutting with a moving high energy pulsed laser

A computational model for simulation of pulsed laser-cutting process has been developed using a finite element method. An unsteady heat transfer model is considered that deals with the material-cutting process using a Gaussian wave laser beam in a pulsed mode. An iterative scheme is used to handle the geometric nonlinearity due to the melting region. The convergence study with mesh refinements and time steps first identifies optimal mesh and time step for the present analyses. Numerical analyses are carried out on the amount of material removal and groove smoothness with laser power (LP) and number of pulses (NPS) while other laser cutting parameters are fixed. The results show that there exist threshold values in number of pulses and laser power in order to achieve two predetermined conditions: (1) amount of material removal and (2) smoothness of groove shape. These values form an envelope called threshold curve that separate the acceptable region from unacceptable one for quality pulsed laser cutting. The effect of velocity also leads to another threshold curve which is determined from both number of pulses and velocity. Finally, the convergence of results in error domain is shown oscillating due to geometric nonlinearity.