A return time compensation scheme for complex geometries in electron beam powder bed fusion
Christoph Breuning, Matthias Markl, Carolin Körner
Abstract
The defect-free fabrication of complex geometries with homogeneous properties using line-based hatching strategies remains a major challenge in electron beam powder bed fusion (PBF-EB). Open PBF-EB machines enable the development of new scanning-strategy-based compensation schemes to solve this challenge. This study introduces a new return time compensation scheme for line-based hatching strategies in PBF-EB, that enables the fabrication of complex geometries with a homogeneous melt pool geometry over constant cross-sections in build direction. Using thermal simulations and melt surface analysis, it is shown that the proposed compensation scheme prevents geometry-induced defect formation in two complex model geometries, in comparison with basic line-based hatching strategies. It is illustrated that the developed compensation scheme has the potential to transfer arbitrary melt pool geometries to complex parts. Ultimately, the universality of the return time compensation scheme is demonstrated and compared to existing process-parameter based compensation schemes.