Robust Spot Melting by 3D Spot Arrangements in Electron Beam Powder Bed Fusion

In order to increase the productivity of the build process in electron beam powder bed fusion via spot melting, higher beam powers with larger melt spot sizes are commonly used. While these process modifications can improve productivity, they also lead to a coarser representation of the part's geometry. The current state‐of‐the‐art countermeasure is to split the melt area into an infill area and a contour area. However, the split‐up introduces challenges, such as an increased energy input, a transition area prone to defects, and the need for separate contour parameters. The proposed spot arrangements decouple boundary spots from the fixed lattice and combine this with stacking, i.e., lateral displacements between successively melted layers. While stacking reduces the risk of porosity in the infill, it also allows the contour to be processed simultaneously with the infill using the same beam parameters, thereby eliminating the defect‐prone transition area. The benefits of the proposed approach are demonstrated on parts of varying complexity, supported by electron optical images, micrographs, and tactile roughness measurements.