ELECTRICAL STEEL FABRICATED BY BINDER JET PRINTING

ABSTRACTELECTRICAL STEEL FABRICATED BY BINDER JET PRINTINGBinder Jet Printing has been a promising additive manufacturing (AM) technique since it was first patented 30 years ago. The nature of its densification process is similar to powder metallurgy. Compared to other methods such as powder bed fusion and direct energy deposition, it provides many unique benefits, minimal residual stress, cost-efficient scaling up, higher powder reusability, etc. However, for most metals, the final density obtainable from the binder jet printing is low compared to other AM methods, making the technique only suitable for few materials or limited in applications such as prototyping. This study implemented liquid phase sintering and a linear packing model to achieve high-density electrical steel starting from pure elemental powders as well as pre-alloyed powders. Boron and Silicon were used as additives to form a eutectic composition with Iron to achieve liquid phase sintering. The elemental powder approach investigated the effect of Boron and Silicon on mechanical and magnetic properties with the ANOVA technique. The alloyed powder approach with Boron and Silicon as additives achieved the final density of 7.39 g/cc (98.4% of the theoretical density 7.51 g/cc), 8489.75 in maximum permeability, 0.053 Ws/kg for hysteresis loss at 1.5T, and a total loss of 34.39 W/kg for the frequency at 400Hz and 0.5T. These values can be compared to Cramer et al. [1] which achieved the final density of 7.31 g/cc (97.3% of the theoretical density of 7.51 g/cc), 10500 in maximum permeability, and 62.85 W/kg at 400Hz and 0.5T. With the processing parameters implemented, the stator with internal cooling channels was made with a unique joining technique. It shows that binder jet printing is a promising technique for fabricating free-form electrical steels without the preferred orientation offered by sheet lamination but with improved strength and density compared to soft magnetic composites.[1] C. Cramer, P. Nandwana, J. Yan, S. Evans, A. Elliott, C. Chinnasamy and M. Paranthaman, "Binder jet additive manufacturing method to fabricate near net shape crack-free highly dense FE-6.5 wt.% Si Soft magnets," Heliyon, vol. 5, no. 11, 2019.