Unit process energy consumption analysis and models for electron beam powder bed fusion (EB-PBF): Effects of chamber saturation

According to the state-of-the-art literature, electron beam powder bed fusion (EB-PBF) processes have the highest energy efficiency (i.e., Specific Energy Consumption - SEC) and the highest deposition efficiency (i.e., average Deposition Rate - DRa) among other additive manufacturing (AM) techniques. The relationship between SEC and DRa is hyperbolic and it has been demonstrated that the energy efficiency of EB-PBF is strongly dependent on the machine architecture and the process control, while the design complexity influences the deposition efficiency at the layer level. However, for a sustainable manufacturing, it is necessary to analyse the job design from a wider point of view that considers the entire build chamber. This study presents an experimental investigation into the effect of the build chamber saturation on the time and energy efficiency of the EB-PBF process. The time and the energy efficiency of ad-hoc designed jobs, including different geometries, material processing conditions (bulk, support and lattice), start plate saturation, build chamber saturation, and job height, have been studied. The results indicate that the presence of lattice structure and the increase of the chamber saturation are the most affecting factors on the time and energy efficiency metrics. Remarkably, the dependency between the specific energy consumption and the build chamber saturation is hyperbolic. The study shows that the build chamber saturation significantly affects the energy demand only up to a specific threshold equal to around 10%.