Mikroskopisches Stützendesign für die nass-chemische Nachbearbeitung von LPBF-gefertigten Bauteilen aus AlSi10Mg

A promising approach for the removal of support structures of LPBF manufactured parts (Laser Powder Bed Fusion - LPBF) is wet-chemical removal, in which the support structures are chemically dissolved and thus separated from the part. This means that internal support structures (e.g. in cooling channels) can also be removed. However, a major obstacle to the widespread use of wet chemical finishing processes at present is the lack of adaptation of the support design to the finishing process. According to the state of the art, the support structures are usually adapted to the LPBF process in order to guarantee a safe process. Usually a combination of single melt traces (so-called vector supports) and volume material (so-called volume supports) is used. While the vector supports are suitable for the wet chemical process, volume supports can only be dissolved with delay due to their small surface area. However, they are indispensable for the LPBF process in order to reduce warpage and enable process heat dissipation. This results in a conflict of objectives in support design. In order to solve this conflict, the present study examines the extent to which the support structure can be modified by adjusting the LPBF process parameters in order to achieve a faster material removal of the supports in comparison to the component. In addition, it will be investigated how the material is removed on the part surface by the reactive medium. The results should draw conclusions about the homogeneity as well as the size of the part allowance. Furthermore, the influence of the modified microstructure on the support structure strength and material removal will be investigated. In the final step, the applicability of the results is checked by transferring them to a demonstrator part.