Magnetic Nozzle-Free Embedded 3D (MagNoFE3D) Printing

The functional principle behind extrusion-based printing is the capability of flowing material through a nozzle on demand, which must solidify upon deposition, a behavior exhibited only by some materials. Embedded printing offers a solution to maintain shape fidelity during the deposition of a wider range of materials. However, the use of a moving nozzle in a support bath can lead to bath disturbance and the spreading of the ink. In this study, a novel embedded printing technique that eliminates the need for a nozzle by employing a magnetic sphere as the plotting moiety is introduced. The externally steered sphere creates a path by locally fluidizing the bath, allowing the simultaneously injected ink to flow into the space behind it. The method is benchmarked using water as an ink, achieving free-form printing without additional stabilization methods. The creation of solid structures is also demonstrated by printing a photocurable ink that is crosslinked and removed from the bath. Moreover, the plotting magnet can be incorporated into the printed part during the crosslinking, thus giving place to a magnetically responsive structure. This advancement paves the way for innovations in fields such as tissue engineering and microrobotics by enabling the fabrication of intricate and functional designs.