Surface topography in three-dimensional laser machining of structural alumina

An integrated experimental and computational approach was adopted to study the influence of moving laser beam (with lateral and transverse overlap) on the generation of corresponding surface finish//profile/roughness during three-dimensional laser machining of structural alumina. A multiphysics-multistep computational model was developed to understand the influence of various physical phenomena such as recoil pressure, Marangoni convection, surface tension, and cooling rates over the surface morphology of alumina and eventually establish the relationship between the surface finish and process parameters of laser machining. Both experimental and computational results evidently revealed that the selection of appropriate laser machining conditions can machine the structural ceramics with higher material removal rates (60 +/- 2.70 mm(3)/min) for initial rough cuts as well as produced higher surface finish (39.9 +/- 2.29 mu m) for final finishing. The results of the computational model are also validated by experimental observations with reasonably close agreement (+/- 6%). (C) 2015 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.