Copper combines both high electrical and thermal conductivity, making it the material of choice for applications in thermal management, electronics and generation of electromagnetic fields. Additive manufacturing (AM) technologies can overcome design restrictions of conventional manufacturing technologies and, therefore, increase geometrical complexity of heat exchangers, moulds with conformal cooling channels and induction coils made of pure copper. Electrical and thermal conductivity of copper can be decreased tremendously by impurities, making high-purity processing technologies essential. Selective Electron Beam Melting (SEBM) is a vacuum AM technology without need
of process agents and, thus, suited for processing high-purity materials, like copper. In the present study, a wide process parameter window for 99.95 % pure copper parts with densities exceeding 99 % is developed by Design of Experiments (DoE) approach. Influences of beam current, scan speed, hatch distance and beam focus offset on part density are quantified and a quadratic model for predicting part density with different SEBM parameter sets is derived. Experiments show no significant influence of these four SEBM parameters on resulting microstructure, which consists of fine columnar grains parallel to build direction. Analytical temperature field simulations using the Rosenthal model
suggest strong influence of SEBM preheating temperature on thermal gradients and cooling rates at the solidification front of the melt pool and, thus, on microstructure of copper parts. Electrical and thermal conductivity, microhardness and Young’s modulus were analysed in as-built condition.