Robohand Uses 3-D Printing to Replace Lost Digits

The device looks like a robot’s hand in a science fiction movie, costs about $500 to make and can be reproduced using plans on the Internet and a 3-D printer.

Richard Van As, a South African carpenter, lost four fingers from his right hand to a circular saw two years ago.

He was unable to afford the tens of thousands of dollars to get a myoelectric hand, which detects a muscle’s electric impulses to activate an artificial limb.

“After my accident, I was in pain, but wouldn’t take painkillers. I barely slept, and the more pain I had the more ideas I got,” he told The Associated Press. “Sometimes you have to chop fingers off to start thinking.”

He decided to build his own hand. After seeing a video posted online of a mechanical hand made for a costume in a theater production, he reached out to its designer, Ivan Owen, in Seattle.

Enter Robohand – a device that Van As and Owen invented that is made from cables, screws, 3-D printing and thermoplastic. It uses the rotation of a joint to enable five plastic digits to grasp. The device looks like a robot’s hand in a science fiction movie, costs about $500 to make and can be reproduced using plans on the Internet and a 3-D printer.

Van As is now on a mission to spread the mechanism to people without fingers or hands all over the world. The two gadget-lovers collaborated on developing a design for the device for a wide range of ages that could be used to grab objects, unlike most existing arm prostheses. Van As has fitted Robohands on about 170 people, from toddlers to adults, thanks to donations.

At first they used a milling machine, making Van As a metal robotic forefinger digit that helps him work in carpentry to this day. That’s when they perfected the shape for the robotic fingers.

“Ivan was a gift to me,” Van As said.

Then they turned to 3-D printing which creates the device in plastic. The 3-D printer gives much greater flexibility, allowing the device to be re-sized on the computer for each user and then manufactured through the printer. A glove-like covering is fitted in thermoplastic, and then fingers are created on the 3-D printer by melting and stacking plastic to make Lego-like digits which are connected to the glove with small cables and screws.

The team got a boost when two printers were donated by the Brooklyn-based Makerbot, one for use in Johannesburg and the other for Seattle.

“What was taking us two weeks to put together took us 20 hours,” Van As said. He opened drawers full of bolts, screws and leftover hinges from the beginning phases of the project. “Now it looks easy.”

They then started working on a design to help children with Amniotic Band Syndrome, a condition where children are born without appendages because their circulation is cut off in the womb by amniotic bands.

To spread the device as widely as possible, they made the Robohand an Open Source design available online, and Van As now collects donations to make hands for people around the world.

“I don’t want to make money out of misery,” Van As said, dismissing the idea that he could make a profit on the mechanical hand.

Robohands are different from other prostheses for three simple reasons: “functionality, simplicity and cost,” Van As said.

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