3D Printing of Small-Scale Soft Robots with Programmable Magnetization

Soft magnetic structures having a non-uniform magnetization profile can achieve multimodal locomotion that is helpful to operate in confined spaces. However, incorporating such magnetic anisotropy into their body is not straightforward. Existing methods are either limited in the anisotropic profiles they can achieve or too cumbersome and time-consuming to produce. Herein, a 3D printing method allowing to incorporate magnetic anisotropy directly into the printed soft structure is demonstrated. This offers at the same time a simple and time-efficient magnetic soft robot prototyping strategy. The proposed process involves orienting the magnetized particles in the magnetic ink used in the 3D printer by a custom electromagnetic coil system acting onto the particles while printing. The resulting structures are extensively characterized to confirm the validity of the process. The extent of orientation is determined to be between 92% and 99%. A few examples of remotely actuated small-scale soft robots that are printed through this method are also demonstrated. Just like 3D printing gives the freedom to print a large number of variations in shapes, the proposed method also gives the freedom to incorporate an extensive range of magnetic anisotropies.

Automated summary

Soft magnetic structures with non-uniform magnetization profiles can achieve multimodal locomotion in confined spaces. Nevertheless, incorporating magnetic anisotropy into these structures is challenging. The existing methods are either limited in achieving anisotropic profiles or too complex and time-consuming. This study demonstrates a 3D printing method that directly incorporates magnetic anisotropy into soft structures, providing a simple and time-efficient prototyping strategy for magnetic soft robots. The proposed process uses a custom electromagnetic coil system to orient the magnetized particles in the magnetic ink during printing, resulting in structures with orientation levels between 92% and 99%. The method allows for a wide range of magnetic anisotropies to be incorporated, as demonstrated by various remotely actuated small-scale soft robots printed using this method.