4D Printing of Electro-Permanent Magnets via Selective Laser Sintering

Magnetic actuation in soft robotics requires compact, low-power solutions capable of precise and reversible control. Traditional magnetic actuators often fall short due to the continuous power needed to maintain magnetic fields. Electro-Permanent Magnets (EPMs) present a compelling alternative, offering bistable magnetic switching without sustained energy input. In this work, we present a 173 mm³ EPM fabricated using a 4D printing approach based on Selective Laser Sintering (SLS), enabling precise spatial control of magnetic composite placement. The printed structure combines FeSi (soft), AlNiCo38 (semi-hard), and NdFeB (hard) ferromagnetic microparticles in a single monolithic device, demonstrating a new strategy for miniaturized, programmable, and energy-efficient magnetic actuators.