# An Additively Manufactured Fe-3 Si Stator for a High-Performance Electrical Motor
## 1 Introduction
AM enables the weight reduction of electrical machines by assisting the manufacturing of complex-designed reduced-volume parts with tailored microstructures with a controlled manufacturing sequence not available in traditional subtractive manufacturing. [PERSON] et al. reported a managing steel (Ni: 17-19 wt.%; Co: 8.5-9.5 wt.%; Fe: balance) 3D-printed synchronous reluctance motor [5]. [PERSON] et al. reported printing a Fe-5%Si soft magnetic rotor with three differently printed sections for a switch reluctance motor and compared it with a conventional switched reluctance machine using the laser powder bed fusion method [2]. They reported comparable performance of the AM electrical machine except for a larger eddy current loss from the rotor core due to its nonlaminated structure. Since the AM-produced part surfaces need to be machineddown to maintain the tight tolerance specifications, there is also the risk of damaging the AM-produced parts. Fe-3 wt.% Si (hereafter Fe-3 Si) is another popular soft magnetic alloy due to its higher machinability via cold rolling, moderate electrical resistance, and moderate saturation magnetization. Typically, Fe-3 Si laminates are made through vacuum arc remelting of the alloy ingots, billet conditioning, surface graining, hot rolling followed by cold rolling, and after stress annealing followed by slitting to the required length for stamping, coating, and stacking. AM can reduce the number of steps for processing these alloys as well as allow for printing of the entire stator in bulk and electrical discharge machining (EDM) to process the laminates. [PERSON] et al. reported the SLM of Fe-3 Si for a transformer core and analyzed the influence of the scan pattern and geometry on the microstructures and magnetic properties [17]. They used transverse, longitudinal, and rotated scanning patterns in a layer-by-layer printing scheme for parallel plates, meshes, and Hilbert geometries to print the test samples. They found that the novel Hilbert curve scanning geometry is more effective in eddy current reduction, which suggests that novel scanning geometries would be beneficial in high-performance electrical machine manufacturing. In other research, [PERSON] et al. reported the AM of Fe-3 Si and Fe-6 Si transformer cores using the Hilbert curve and compared the performance with conventionally processed Gauss textured cores [18]. The low performance of Fe-6 Si compared to Fe-3 Si was attributed to additional defects associated with machining the transformer core assembly. [PERSON] et al. reported the soft magnetic rotor active part (2.9% Si-containing Fe-Co alloy) and shaft for a permanent-magnet synchronous machine using laser beam melting [19]. They outlined the need for a stricter method of tolerance maintenance in AM of electrical machines, which suggests that Fe-3 Si needs further investigation in electrical machine manufacturing. The final assembly of additively manufactured electrical machines needs some degree of machining and assembly, which further affects the magnetic properties of the printed electric cores and the overall performance of the electrical machines. It was discovered in 1900 that the addition of Si improves the soft magnetic properties of steel. Up to a certain extent, as Si content increases, magnetic permeability increases. This is due to low magnetostrictive coefficients and low magneto-crystalline anisotropy. As Si content increases, the eddy current losses decrease. This is due to the increase in electrical resistivity. The higher the Si content, the higher the intrinsic resistivity of the material. The magnetic anisotropy of the material also decreases with increasing Si content. This results in lowered magnetic hysteresis losses while also ensuring that the magnetic properties of the material are more isotropic. Magnetic anisotropy is the ease or difficulty of magnetization in certain directions compared to others.