In a bid to advance prosthetics technology, engineers from the Florida Atlantic University (FAU) have built a new technology to activate the movement of a 3D-printed bionic finger, producing a robotic finger that appears and moves just like a real one.

To build the most lifelike design, researchers downloaded from a website a 3D model of a person's real digit and used a 3D printer to build the outer and inner molds.

The bionic finger houses two actuators—the extensor and flexor actuators—as well as a position sensor. These actuators allow the robotic finger to remember and return to the original shape even when deformed or bent, as long as they are heated. The Shape Memory Alloys (SMA), which researchers used in creating the finger, make this possible.

When heat is applied, the flexor actuator curves, while the extensor actuator, straightens up.

"Thus, alternately heating and cooling the flexor and extensor actuators caused the finger to flex and extend," reads the abstract of the paper [pdf] published on IOPScience.

Moreover, the finger comes with an electrical chassis, aimed to permit electric currents to pass through the flexor and extensor actuators.

“We have been able to thermomechanically train our robotic finger to mimic the motions of a human finger like flexion and extension,” said Dr. Erik Engeberg, assistant professor in the Department of Ocean and Mechanical Engineering at FAU. “Because of its light weight, dexterity and strength, our robotic design offers tremendous advantages over traditional mechanisms, and could ultimately be adapted for use as a prosthetic device, such as on a prosthetic hand.”

However, Engeberg said that an array of challenges exist with the new technology, including how much time it requires for the finger to cool down and get back to its original shape.

As such, the team has decided to initially use the innovation for underwater robots, as the environment makes speedy cooling feasible. Underwater robots can specifically assist humans to address challenges when working in the ocean depths, for instance.

The team's paper, titled "Anthropomorphic finger antagonistically actuated by SMA plates," was developed by Erik Engeberg, Savas Dilibal, Morteza Vatani, Jae-Won Choi and John Lavery.