Appropriate regimes of laser drilling models containing melt eject mechanisms

The significance of melt ejection during various drilling regimes of laser drilling is investigated. The predictions of two analytical models of the drilling process, with and without the melt ejection mechanism, are compared with experimental measurements made using a free-running Nd:YAG laser over a wide range of drilling conditions in aluminum and titanium. The importance of modeling the melt expulsion process is discussed in various drilling regimes. The significance of obtaining reliable model predictions is considered by investigating the dependence on the temporal structure of the drilling pulse. With titanium, discrepancies between the experimental measurements and model predictions are observed and the reactive nature of this material is considered as a source of discrepancy.