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Laser polishing is a technique for smoothing the surface of metallic substrates. The roughness after polishing does not only contain remains of the initial surface roughness, it also contains new roughness due to surface structures, which are introduced by the polishing process. Since these structures greatly contribute to the roughness, it is necessary to understand the mechanisms that lead to their formation so as to prevent the structures from forming and allow higher smoothing of the surface. Hence, in this publication it is investigated experimentally and numerically why these structures occur, what the influencing parameters are and how their influence on the roughness can be reduced, for both laser macro and laser micro polishing. It could be seen that the structures are influenced by the process parameters and the material of the workpiece. For a low surface roughness, the process parameters have to be adapted antithetically in some cases which means that it is not possible to prevent all structures at the same time and that surface structures will always occur during laser polishing. The process parameters must be adapted in such a way that all structures together lead to a surface roughness as low as possible.

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In the present paper, laser micro polishing of TiAl6V4 is investigated with main focus on increasing the area rate by using high pulse energy. First, the influence of the laser beam size, the scanning velocity, and the track distance on the final roughness is examined since these parameters determine the area rate. The results of these investigations are used to identify a set of process parameters that allow increasing the area rate and achieving a surface roughness comparable to state-of-the-art laser micro polishing. The results show that the laser beam size must exceed a critical size; otherwise, smoothing of the surface is limited, which leads to higher final roughness. The scanning velocity and the track distance do not have a great effect on the final roughness for the investigated regimes. However, with decreasing track distance, the number of undesirable surface structures, presumably resulting from evaporating vanadium compounds, is reduced. Additionally, the heat input into the surface decreases with increasing laser beam size, scanning velocity, and track distance. The results of these investigations are used to significantly increase the area rate to 19.1 cm2/s, which is a factor of 64 times faster than the state of the art. The final surface roughness is comparable to state-of-the-art laser micro polishing in this case.