Superconducting radio frequency (SRF) cavities are used to accelerate charged particles to near the speed of light for elemental studies. Currently, SRF cavities are typically fabricated using different forming processes including deep-drawing and spinning to mechanically shape niobium into the desired geometry. This research presents the development of processing parameters for high purity niobium (powder size range of 25-125μm) using electron beam melting additive manufacturing technology. Fabrication parameters were improved to obtain dense parts in a time-efficient manner. A specific procedure was used to maintain powder purity, and powder chemistry was monitored at different stages of fabrication. In addition, a series of experiments were performed to obtain 99.9% dense parts and a maximum building height of ~85mm.