Features

Have you heard of Robohand? No, it’s not the next sci-fi blockbuster. It’s a story of compassion, technology, and a collaboration from 10,000 miles apart between Richard Van As, a woodworker from Johannesburg, South Africa, and Ivan Owen, a theatrical prop designer from Seattle, Washington. And it was all made possible thanks to MakerBot’s sharing website Thingiverse.com and 3D printing on a MakerBot® Replicator® 2 Desktop 3D Printer.

Fig. 1 – Van As was able to assemble the Robohand himself using 3D printed parts and cabling, hardware, and a gauntlet made of thermoplastic.
In 2011, Van As severed four fingers on his right hand in a woodworking accident. As he struggled with finding a cost-effective means of creating substitute fingers for those that were gone, he discovered that that custom-made prosthetic fingers cost upward of $10,000 per finger.

After considerable research online, Van As found a video that Owen, who specialized in mechanical hand props, had posted on YouTube. These two non-experts made contact and collaborated via e-mail, photos, drawings, and video chat sessions to create a design for working fingers that could be inexpensively built. After trying numerous types of materials, the pair hit upon the idea of using a 3D printer.

How It Works

A Robohand is a set of fingers that open and close to grasp things based on the motion of the wrist. When the wrist folds and contracts, the cables attaching the fingers to the base structure cause the fingers to curl. Nearly all the parts of a Robohand are made on MakerBot Replicator 2 Desktop 3D printers.

The design of Robohand is done on the computer, using free software that anyone can access. There is no patent on the design, and the actual design file is similarly freely available online, along with instructions on how to adapt the design to an individual hand. Whereas before, someone needing prosthetic fingers would need to go to a specialist for a customized product, with Robohand they can make one at home.

The collaboration was taking a long time, months at a time, which was frustrating for both parties. The pair knew that if they could hit upon the right materials and construction method, things would click. They decided that 3D printing was the right way to go, but neither could afford the cost. That’s when MakerBot stepped in.

According to Bre Pettis, CEO of MakerBot: “For us here at MakerBot, that was too much wasted time. We knew our 3D printer, the MakerBot Replicator 2 Desktop 3D Printer, could take this important work to new heights. We saw their collaboration and the work they were doing as ground-breaking, and we asked them to accept a donation from us: one MakerBot Replicator 2 Desktop 3D Printer for each of them—one in Washington state, and the other in South Africa.”

Van As said, “Just hours after receiving our MakerBots from Brooklyn, NY, we were sharing files back and forth, testing the design on one side of the world, and doing another iteration on the other side. Each of us having a MakerBot Replicator 2 Desktop 3D Printer took the prototyping process down from weeks to just 20 minutes.” Van As was able to assemble the working hand himself. (See Figure 1)

Giving Children a Helping Hand

Fig. 2 – Liam can use his new hand to pick things up and throw a ball, just like a real hand.
With Robohand, Richard began to realize how quickly he could refine the design for other people who have lost their fingers, or who were born without fingers. After posting his own story, he received e-mails and Facebook messages from parents whose children would be perfect candidates for a Robohand of their own. One of these children was five-year-old Liam.

Liam suffers from a birth defect called Amniotic Band Syndrome (ABS) that affects babies in the womb. Fibrous bands prevent their extremities from developing normally and children are often born without fingers and toes. Liam was born with no fingers on his right hand. Purchasing a traditional prosthesis was cost-prohibitive, especially since Liam is a fast-growing little boy who would outgrow prosthesis in a few months.

Liam was given a Robohand in January 2013, just days after Van As and Owen received their MakerBots. Since he is growing quickly, he has already been fitted for his second Robohand. (See Figure 2) The word spread, and other children with ABS in South Africa, wanted their own Robohands, sized just for them. Individual Robofingers are now available, too.

Van As explained that the hand they developed for ABS children and adults is driven by the wrist motion. “They don’t have the fingers, and generally, they only have the palm, and no thumb. So it’s attached to a hand cap and gauntlet, and to that is attached cabling.” When you bend your wrist forward, it makes the fingers close, and when you bring it up, it opens the fingers.

Everything is made by the 3D printer, except the cables, the stainless steel hardware, and the thermoplastic. The fingers and the phalanges, the tips, the thumb, the knuckle block, the wrist hinges, are all printed. He recommends that if a parent is making this for their child, that they find an occupational therapist to help out with cutting and fitting the gauntlet and the hand cap, but says that it’s not impossible to do the whole thing yourself.

To view a video of Van As discussing the technology and some of the children it has helped, visit http://www.techbriefs.com/tv/robohand.

Where It Stands

For a full set of open source designs and assembly instructions for customized, fitted, mechanical hands and fingers, see Robohand on Thingiverse at http://www.thingiverse.com/robohand/ overview. People around the globe have now downloaded the design more than 19,500 times.

There are files available for both right and left hands, as well as various sizes, and a parts manual available.

MakerBot was founded in 2009, and has since sold more than 22,000 3D printers, with its most recent model making up 11,000 of those sales coming from the Replicator 2, which it launched back in September 2012. In late June, Stratasys, based in Minneapolis, MN, and Rehovot, Israel, acquired MakerBot. MakerBot will continue to operate as a separate company as a subsidiary of Stratasys, but will serve the consumer and desktop market segment while Stratasys focuses on its existing industry placement.

For more information on the Robohand story, visit http://robohand.net. For information on MakerBot, Brooklyn, NY, visit http://info.hotims.com/45608-165.