Process modelling of laser ablating ferrous materials

摘要

Based on experimental results, a qualitative process model for reactive ablation of ferrous materials is suggested, which includes the absorption of the radiation to the workpiece, oxidation of the workpiece material, formation of a chip or wedge and removal of the oxide by bending perpendicular to the workpiece. The superior role is ascribed to the exothermal reaction of the matrix material by increasing the absorption and thus initiating a stationary process of either chip or wedge formation. The model is verified by different experiments, comparing the ablation results of steels with varying carbon content and therefore different heat conductivities, the importance to the process of which becomes obvious in the phenomenon of the sudden transition from chip removal to wedge removal. The influence of impurities on the formation of the chip is explained as well as the mechanism of chip bending.