(56c) Direct Write of UV Curable Polymer Bonded Magnets

Today, almost all commercial magnet producers are using the conventional sintering-based procedure to manufacture magnets. Polymer-bonded hard magnets have recently gained popularity as a novel magnet manufacturing technique due to its design freedom regarding shapes and magnetizing structures. Comparing to the conventional sintering process, the maximum energy product (BH)_max of the polymer-bonded magnets is lower. However, the fabrication of polymer-bonded magnets does not require high temperature treatment and thus can be more efficient. Furthermore, no current mass production technologies can produce magnets with complex geometries.

This work utilizes extrusion-based direct write (DW), combined with UV curing, to fabricate polymer-bonded magnets at room temperature. DW is an additive manufacturing technique enabling the deposition of electronic components and functional or structural patterns using different types of materials, directly without utilizing masks or subsequent etching processes. Compared to the molding process, DW provides intricate details and smooth surface finish. In this work, Nd-Fe-B powder are directly mixed with photo-curable binders to form a printable DW ink. Experiments were carried out to understand the relationship between magnetic powder solid loading, processing, and mechanical strength. Magnetic performance of printed parts was compared to other polymer-bonded and sintered magnets. The study opens a new pathway for preparing polymer-bonded magnets at room temperature for various magnetic applications.