Process Parameter Effects on Melt Topology and Dimensional Deviation in Electron Beam Melted Ti-6Al-4V

Abstract

Abstract Industry is actively evaluating additive manufacturing (AM) for parts and assemblies, but many applications have strict requirements that manufacturing processes be stable and repeatable. This is currently a challenge for many operators of powder bed fusion (PBF) technologies where limited understanding of how the AM process parameters impact the dimensional deviation from the design and material quality. The experiment described in this paper employed an electron beam melting (EBM) Arcam A2X and Ti-6Al-4V powder to manufacture single lines of melted powder within the bed. This fundamental approach was designed to identify variation and inaccuracy at the micro scale that could provide lessons applicable to the macro scale. It is a subset of a broader ongoing effort intended to characterize the manufacturing repeatability of the EBM PBF process. The design of this experiment involved the placement of short line segments in various orientations within the build plane. Two different sets of process parameters were utilized to fabricate the CAD build geometry. Each line specimen was imaged and 3D scanned within the surrounding sintered powder to study the topology. Observations from the resulting measurements were correlated with the machine process parameters and log file data. The dimensional deviation of the melt - was characterized along with the minimum feature size. These findings provide valuable EBM design for additive manufacturing guidance to help improve quality and limit deviation in components produced for industrial applications.