UV-assisted direct write of polymer-bonded magnets

Abstract

This work presents a novel fabrication technique called “UV-assisted Direct Write (UADW)”, which combines extrusion-based direct write (DW) and in situ layer-by-layer UV curing to fabricate polymer-bonded permanent magnets of arbitrary shapes at room temperature. The process requires minimal post heat treatment and therefore preserves the magnetic properties of the raw powder in the printed product. Experimentation achieved a maximum solid loading of printable ink of 60% by volume, or 91% by weight. Samples with 60 vol.% nominal particle concentration exhibited remanence of 3.80 kG (52% of raw powder value) and intrinsic coercivity of 9.50 kOe. Magnetized samples showed no reduction in intrinsic coercivity, which proves good curing of the final product and good bonding between particles and binder. Compared to other 3D-printed magnets reported in the literature, UADW magnets possess the highest intrinsic coercivity with one of the highest magnetic remanence values.