3D Printing a Motor--Some First Steps
MIT researchers recently published "Fully 3D-Printed electric motor manufactured via multi-modal, multi-material extrusion" full text and nice illustrations available at https://www.tandfonline.com/doi/full/10.1080/17452759.2026.2613185 To do this required modifying a 3D printer, a lot of experimentation with feedstock, and software changes to solve printing problems. When they got done they have something they call a linear motor, but it looks more like a voice coil or solenoid (very short stroke) to me. None the less, it is proof of concept that printing both conductors and magnetic materials is possible.
In this work, a commercial multi-material extrusion 3D printer was modified to process conductive inks, soft and hard magnetic composite pellets, and rigid and compliant polymeric filaments. Using this system, solenoids, hard magnets, and springs were fabricated. These components were combined through straightforward assembly to demonstrate the first fully 3D-printed electric motor - a linear actuator composed of five distinct functional materials: dielectric, electrically conductive, soft magnetic, hard magnetic, and flexible. The solenoids produced up to 2.03 mT magnetic fields, the magnets generated up to 71 mT magnetic fields, and the linear actuator attained a maximum displacement of 318 m at its resonant frequency (41.6 Hz). This study demonstrates the capability of multi-modal, multi-material extrusion 3D printing to fabricate all critical components of electrical machines, with magnetization of the hard magnets being the only post-printing step.
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The potential of material extrusion 3D printing for the fabrication of electronics has led to the development and commercialization of several electrically conductive filaments, often made of polymer-based composites doped with metallic (e.g. copper [Citation20]) and carbon-based (e.g. graphene [Citation65]) fillers. Among the commercially available electrically conductive filaments, Electrifi (Multi3D, Middlesex, NC, USA) - a copper-reinforced PLA filament - is, to the best of our knowledge, the most electrically conductive. However, its resistivity, in the order of 10-4m [Citation20], is still considerably high - about four orders of magnitude larger than that of bulk copper. This circumstance suggests the need to consider other forms of printable feedstock, such as inks and pastes, to be able to attain higher conductivities.
They wound up using pellets of silver-loaded conductive ink, along with a special/overlapping printing pattern to limit local spots of higher resistance.
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