3D Printing Magnetic Material with Arbitrary Anisotropy

A process for 3D printing of magnetic materials with programmatically controlled anisotropy is presented. Using an experimental thermal inkjet printer magnetic structures with and without anisotropy are printed and characterized to demonstrate the unique advantage afforded by inkjet printing – that of arbitrarily controlling the anisotropy orientation within the structure during printing. The technique will make possible 3D printed inductor and transformer cores with low losses, antenna loading materials and graded index lenses for processing microwave signals, and magnetic field sensors to name a few applications. In the inkjet printing technique presented here, a magnetic ink composed of magnetic nanoparticles in a UV curable resin is jetted on the substrate. The nanoparticles are then aligned in a magnetic field generated using a two-axis electromagnet and the ink cured to obtain a composite with the desired magnetic anisotropy. The process is repeated to fabricate a 3D structure of the desired shape and dimensions.