Influence of the beam power on the density of pure copper samples in PBF-EB/M using a spot melting strategy

Abstract Pure copper is well-suited for the powder bed fusion of metals using an electron beam. The main reason is that the high reflectivity of the copper powder is non-critical for the energy coupling of the electron beam compared to the laser beam in the powder bed fusion of metals using a laser beam. However, due to the high thermal conductivity of pure copper, it is necessary to adjust the energy input to achieve sufficient melting while avoiding process defects from local overheating. To achieve this, a self-developed spot melting strategy is applied to manufacture pure copper samples with a homogeneous energy input and thermally independent melt pools. In an experimental study, this paper investigates the influence of applied beam power on the density of pure copper samples at constant volume energy density. To investigate the aforementioned research question, the density of the samples was measured using Archimedes’ principle, and to qualify the porosity of the samples, cross sections were observed. Based on the experimental study, this paper shows that optimal beam power can reduce dwell time and thus the time required for heat input. This also shortens the time required for heat dissipation. Therefore, despite copper’s high thermal conductivity, denser samples with lower volume energy density could be produced because heat dissipation was reduced.