In-situ alignment of anisotropic hard magnets of 3D printed magnets

TL;DR

This paper demonstrates in-situ alignment of anisotropic magnetic particles within 3D printed polymers using fused filament fabrication, enabling the creation of magnets with locally defined easy axes.

Contribution

It introduces a method for in-situ easy-axis alignment of magnetic particles during 3D printing, showing feasibility for fabricating anisotropic magnets with arbitrary orientations.

Findings

Strontium hexaferrite particles can be well aligned with a high remanence ratio.

Samarium iron nitride particles showed no significant alignment.

The method allows for local easy-axis control in 3D printed magnets.

Abstract

Within this work, we demonstrate in-situ easy-axis alignment of single-crystal magnetic particles inside a polymer matrix using fused filament fabrication. Two different magnetic materials are investigated: (i) Strontium hexaferrite inside a PA6 matrix, fill grade: 49 vol% and (ii) Samarium iron nitride inside a PA12 matrix, fill grade: 44 vol%. In the presence of the external alignment field, the strontium hexaferrite particles inside the PA6 matrix can be well aligned with a ratio of remanent magnetization to saturation magnetization of 0.7. No significant alignment for samarium iron nitride could be achieved. The results show the feasibility to fabricate magnets with arbitrary and locally defined easy axis using fused filament fabrication since the permanent magnets used for the alignment (or alternatively an electromagnet) can be mounted on a rotatable platform.