Evaluation of electron beam powder bed fusion additive manufacturing of high purity copper for overhang structures using in-situ real time backscatter electron monitoring

Electron beam based additive manufacturing (AM) with copper must consider the high intrinsic thermal conductivity of copper as well as the greater difference between the thermal properties of the AM article and the surrounding or underlying powder bed. Successful processing requires multi-step control of the beam-bed interactions driven by a combination of a priori calculations and real-time monitoring and feedback to achieve melt pool size stability and appropriate bed/article temperatures as thermal boundary conditions vary based on geometry. The objective of this work is to utilize electron imaging to rapidly assess the processing space for copper with a wide shift in thermal boundary conditions using samples with overhang features. A modified commercial Arcam EBM AM system and process parameter space are described that allow successful AM of copper for complex geometries.