Achieving Complex Magnetic Anisotropy via 3D Printing to Incite Complex Motion in Soft Magnetic Elastomers.*

Magnetic elastomers consist of magnetic particles suspended in a flexible elastomeric matrix. Such elastomers are applicable in areas of soft robotics where actuation without a direct line of sight is required. Magnetic elastomers with soft magnetic particulate generally display geometrically simple magnetically-actuated motion at large magnitudes, while samples with hard magnetic particulate display more complex motion, but at smaller magnitudes. The goal of this work is to study how the artificially created anisotropy from 3D-printed part shape and infill orientation can influence the complexity of motion in printed soft magnetic elastomer structures. Samples consist of 15% volume Iron particulate suspended in a thermoplastic polyurethane (TPU) matrix. Four sample beam sets printed with varying initial (-45deg, 0deg, 45deg) and twisting (0deg, 45deg, 90deg) angles are exposed to axial and transverse magnetic fields. Data is captured through images taken of the samples before and during exposure to the magnetic field. These images are then analyzed for degree of rotation and degree of deflection, combining to form complex motion. The complexity of the sample shape directly influences the complexity of the magneto active response of the sample. Samples with larger twist values show a larger rotational and deflection response when exposed to magnetic fields. This shows that complex motion is achievable using only soft magnetic elastomers through artificially structuring the underlying magnetic anisotropy via 3D printing.