Feasibility study of ferromagnetic cores fabrication by additive manufacturing process

Currently, the commercial production of ferromagnetic cores involves staking thin sheets of soft magnetic material, alternating with dielectric material to reduce the eddy current losses. High silicon FeSi steels show excellent soft magnetic properties. Anyway, their workability decreases Si content increases thus imposing a technological limit in the production of thin sheets up to 3.5–4% Si. The additive manufacturing (AM) process based on laser powder bed fusion (L-PBF) offers the possibility to redesign the magnetic components, compared to conventional design, allowing to act on the chemical composition of magnetic materials and on the geometry of the components. In the case of FeSi alloys, the additive technology allows to overcome the limit of Si content opening new perspectives for the production of ferromagnetic cores with high magnetic performance. In this work the feasibility study on the production of FeSi magnetic steel components by L-PBF technology is reported. Two variants of FeSi steels, with Si content of 3.0 wt.% and 6.5 wt.%, were considered. The effect of process parameters on the densification of manufactured parts was investigated. The best operating window has been identified for both steel chemical compositions, in terms of laser scan speed and power.