On gas dynamic effects in the modelling of laser cutting processes

In this paper the author addresses the modelling of the laser cutting process. Despite the attention paid to this process by the scientific community, the underlying physical phenomena are still only marginally understood. The models used in the literature are often highly simplified and focus on single effects such as exothermic reactions of the melt with the assist gas whilst neglecting other important physical mechanisms. In this work a three-dimensional fully coupled model for the laser cutting process is used. It will be shown by the author that simplifications like reduction in model dimension are not admissible for the investigation of the complete process. However, it has also been found by the author that currently available computer hardware is not capable of producing results at the necessary rate and cost required for parametric studies. Results from two simulation runs, which were performed in course of a larger study amounting to 17 300 cpu hours on a SGI origin 3400 system, are presented. Nevertheless, these results form a cautionary example with regard to the numerical models applied and assumptions frequently introduced by other authors.