Build Chamber and Start Plate Variability During Electron Beam Melting Machine Setup

Electron beam melting (EBM) is an additive manufacturing process that utilizes a metallic powder as the feedstock material. During the setup of an Arcam A2X machine, the operator is first required to load the feedstock into the hoppers and set the “zero” position of the start plate relative to the rake. This manual process relies on operator-experience and is hypothesized to have a detrimental impact on process repeatability by modifying the local layer thickness. The potential effect that this has on the as-built quality and performance of EBM-manufactured components is unknown. Therefore, this study presents a device used to measure the variability that exists during A2X machine operations. Consideration is given to both the build basin as well as the start plate during ten machine setups. Assuming a mean particle diameter and commensurate layer thickness of 50 μm for Ti-6Al-4V, data indicate that local thickness deviations greater than ten layers are achievable using the prescribed zeroing routine. These deviations are shown to manifest in the measured mass of specimens within a test build. While not directly considered in this study, a discussion regarding powder pile size during fetching operations and how this may affect bed coverage and build quality is also provided.