Evolution of surface topography in one-dimensional laser machining of structural alumina

High energy lasers are an emerging industrial tool to fabricate complex shapes on hard and brittle structural ceramics such as alumina. The selection of laser processing parameters and the prediction of material removal rates during the laser machining are the critical issues. This paper was attempted to present the state of the art of laser machining of alumina using an integrated experimental and computational approach. A multistep computational model based on COMSOL™ Multiphysics was developed to study the influence of various single-pulse laser energy densities and associated physical phenomena (recoil pressure, Marangoni convection, and surface tension) on the temperature history, fluid velocity, crater size, and surface topography. A pulsed Nd:YAG laser was employed to machine alumina under different processing conditions. The surface topography of laser machined alumina was measured by an optical profilometer and the results were compared with the computationally predicted topographic parameters with reasonably close agreement.