Robotics

Ink port of a printer / Photo by: Boibin via Shutterstock

 

The technology of 3D printing is essential in the production of biomedical devices including soft actuated devices. However, most materials used in this production system respond slowly and take time to change shape. Engineers at the Massachusetts Institute of Technology developed a new method involving magnetism to easily manipulate printing materials.

The materials are made of soft, 3D-printer structures that respond to an external magnetic field. The collection of structures includes a smooth ring that can wrinkle up, a long tube that can squeeze shut, a sheet that can fold, and a spider-like grabber that can crawl, jump, roll, and snap.

The team of engineers also created a special 3D printer ink infused with tiny magnetic particles. For the printing, they attached an electromagnet around the nozzle of a 3D printer so that the ink would flow in a single orientation. It also allowed them to precisely print targeted sections of the soft structures, which gave them the specific magnetic orientation that would react to an external magnetic field.

Through the magnetic ink and precise printing, the engineers were able to control the structures to assume forms or change shapes in seconds. The formation assumed by every structure depends on the distance and direction of the external magnetic field.

“We think in biomedicine this technique will find promising applications,” said Xuanhe Zhao, a professor at the department of mechanical engineering and department of civil environmental engineering at MIT.

The structures can be categorized as soft actuated devices -- moldable components designed to change their shape and move around using different mechanical means. One example is the hydrogel device that swells when exposed to a certain degree of temperature or pH level.

But unlike hydrogels or polymers, the magnetic structures can respond to its controller quickly and can assume shapes rapidly. Also, the magnetic-powered devices enable controllers to manipulate them remotely.

“With this technology reported in this paper, one can apply a magnetic field outside the human body, without using any wiring. Because of its fast responsive speed, the soft robot can fulfill many actions in a short time. These are important for practical applications,” explained Jerry Qi, professor of mechanical engineering at Georgia Tech.