Analysis of Melting and Melt Expulsion During Nanosecond Pulsed Laser Ablation

Manufacturing with nanosecond pulsed lasers is one the most efficient ablation processes and frequently used in the field of micro production. The aim of this study is to analyse the amount of melt expulsion during the laser ablation process of aluminium sheets with a thickness of 200 μm. The amount of recast layer, which deteriorates the surface finish is supposed to be reduced. The influence of the laser parameters on the high speed ablation process are investigated and described. The amount of melt expulsion is analytically calculated and metallurgically obtained. Overall, pulse durations of 120 ns, lower repetition rates of 20 kHz and laser powers between 20 W and 30 W reduce the amount of melt expulsions and melting of the mesh structure surface area. Thus, for these parameters smaller amounts of recast on the mesh surface and higher web accuracies are obtained.