Development of actual powder layer height depending on nominal layer thicknesses and selection of laser parameters

Deniz Jansen, Theresa Hanemann, Markus Radek, Astrid Rota, Jörg Schröpfer, Martin Heilmaier
For an improved understanding and modelling of the melting process and dynamics in laser powder bed fusion the knowledge of the actual powder layer height and its development is essential. According to theoretical calculations the powder layer thickness approaches the quotient of the nominal layer height and the powder layer density after several layers. However, a previous study shows that in this stable state the actual powder layer thickness is much higher than theoretically expected due to
more » ... enudation and spattering. Based on the approach of past investigations this study examines experimentally the development of the effective powder layer height by varying the nominal layer thickness and the laser parameters. Furthermore, the influence of these process parameters on the formation of the denudation zone was examined. The results show the significant impact of the variation of the laser parameters on the actual powder layer thickness likely caused by denudation and spatter effects. Moreover, for low nominal layer heights the effective powder layer thickness is relatively higher. This development seems to be affected by the selection of the laser parameters. The outcomes also provide a possible explanation for the unexpected high increase in powder consumption, which amounts to at least 98% compared to theoretical calculations within the experiments.
doi:10.5445/ir/1000136297 fatcat:duv4o3gsgjeahbwevkne7xd7hu