A 3D printer built by Northeastern University researchers uses magnetic fields to shape composite materials. The mixes of plastics and ceramics can be shaped into patient-specific products, including customized implants and catheters for premature babies.
By controlling how the ceramic fibers are arranged, engineers are able to control the mechanical properties of the material itself.
Within a single patient-specific device, the corners, the curves, and the holes must all be reinforced by ceramic fibers arranged in just the right configuration. Using magnets, the new 3D printing method aligns each minuscule fiber in a direction that conforms precisely to the geometry of the item being printed.
First, the researchers “magnetize” the ceramic fibers by dusting them very lightly with iron oxide. Ultra-low magnetic fields are then applied to individual sections of the composite material — the ceramic fibers immersed in liquid plastic. The fibers align according to the exacting specifications dictated by the product.
Through a final process called stereolithography, the Northeastern team builds the product, layer by layer, using a computer-controlled laser beam that hardens the plastic.
