Geometry-Based Process Adaption to Fabricate Parts with Varying Wall Thickness by Direct Metal Deposition

The process of direct metal deposition gains recently high attention in the additive manufacturing community, but its capabilities to fabricate complex geometries is still limited. Especially for thin-walled structures, heat accumulation can disturb the process significantly. An adaption of process parameters, for instance by a semi-empirical model, is able to stabilize the process. Herein, an algorithm is proposed that creates a digital twin of the part from a given NC code, analyses the massiveness of the part by calculating a local geometric factor, and alters the laser power accordingly: The heat flux in a thin wall is limited compared to a massive plate due to its smaller cross section and requires therefore less laser power to generate a comparable melt pool, especially if waiting times shall be avoided. The algorithm correlates experimentally determined process parameters to the local geometric factor. Since no physical simulation is performed, it is fast, easy to use, and enables a clearly defined and repeatable process. The buildup of a demonstrator part reveals the potential of the parameter adaption to fabricate arbitrary geometries.