Transient, Three-Dimensional Numerical Model of a Laser Cutting Process with Phase Change Consideration

摘要

Phase change problems are encountered in several manufacturing and material processing applications. Such problems are computationally challenging because it is necessary to solve a non-linear heat conduction equation and take into considerations the conditions needed to produce material ablation, varying continuously the heat source position, thermo physical properties and physical shape of the domain. This research presents a numerical simulation of the temperature field and the removed material resulting from the impingement of a moving laser beam on a ceramic surface. A finite volume approach has been developed to predict the temperature field including phase changes generated during the process. The model considers heat losses by convection and radiation due to the high temperatures involved and uses a coordinate system affixed to the workpiece; therefore no quasi-steady conditions are assumed, as in the majority of previous works. Numerical predictions were compared with former three-dimensional numerical models considering a semi-infinite solid and from experimental data found in the literature. This study gives insight into the interactions between the laser beam and a silicon nitride workpiece during the cutting.