Jul 15, 2016 | By Benedict

Team Unlimbited, a pair of British e-NABLE volunteers, has released version 2.0 of its 3D printed prosthetic arm, named the “Alfie Edition” after its first recipient. The new design is fully parametric and can be customized for a correct fit using Thingiverse Customizer.

As the e-NABLE vision spreads further across the globe, more and more volunteers have tried their hand at revamping the classic design of the prosthesis, giving recipients of the 3D printed device a more personal product—in terms of either function or aesthetic design. Stephen Davies and Drew Murray, two British e-NABLE volunteers, wanted to widen the reach of the e-NABLE project, and together came up with “Unlimbited,” a 3D printed below-elbow arm prosthesis which takes inspiration from the original e-NABLE hand.

“When I first became an approved maker for the e-NABLE Community, I was struck by one thing above all else: the number of recipients that were waiting for an arm,” Davies said. “By the time I got involved, there were several hand models available, but for children with below-elbow deficiencies the choice was stark. I felt inspired by several other designs like the Raptor wing from the students at UW Bothell who were working with Ivan Owen on an elbow driven design and I set about to do something to help.”

Davies, who has only one arm himself, had long wanted to put his two decades of professional CAD experience to use for the benefit of the limb-different community. When Murray expressed interest in teaming up with him, Davies immediately set to work on the Unlimbited project, the aim of which was to make a 3D printed arm that was cheap, lightweight, easy to print and assemble, and which required minimum hardware. Following several experimental iterations, the duo eventually released Unlimbited 1.7, along with its open source files, to the e-NABLE community. So far, that Unlimbited arm has been used in the UK, Sierra Leone, Hong Kong, Turkey, America, Uganda, Ghana, and other places.

Despite the massive success of their first 3D printed prosthesis, Davies and Murray knew that, for one important reason, they would have to revisit the design. For while the arm could be scaled up and down to fit recipients of differing sizes, its proportions could not be altered: “This was fine for most children between the ages 4-7, but around the 7-year mark, children’s proportions alter variably as they grow,” Davies explained.

“As makers ourselves, the greatest frustration was the uncertainty of sizing the devices correctly, calculating the print scale for each individual, and ensuring a good fit,” he continued. “We did everything we could to help, providing sizing charts and instructions but it would always be a ‘Best Fit’ scenario and—as recipients’ forearms, hands, and biceps all grow and stretch un-proportionally—this made this process almost impossible. Also, from what we had seen ourselves, and from many emails asking for teenage or adult proportioned arms, we knew we would have to tackle designing a parametric arm.”

After many months of coding and testing their new design, Team Unlimbited has now unveiled version 2.0 of its Unlimbited arm, a fully parametric 3D printed prosthesis. To get a perfectly sized version of the new arm, makers need only specify three key measurements: hand length, forearm length, and bicep circumference, inputting these figures into Thingiverse Customizer. With this data, Customizer can automatically generate an accurately proportioned 3D printed arm for the user.

Team Unlimbited’s relentless efforts to advance the e-NABLE mission serve as a great example to other CAD designers who think they can help with the massive international 3D printing project. If you think you could help, take a look at e-NABLE and Pinshape’s new 3D design challenge, where you can show off your design skills while helping children in need.

Recommend print settings for the Unlimbited arm v2.0:

  • Rafts: No
  • Supports: Yes (palm and cuff only)
  • Resolution: .2mm Layer height
  • Infill: 35% Honeycomb
  • Material: PLA



Posted in 3D Printing Application



Maybe you also like:


Leave a comment:

Your Name:


Subscribe us to

3ders.org Feeds 3ders.org twitter 3ders.org facebook   

About 3Ders.org

3Ders.org provides the latest news about 3D printing technology and 3D printers. We are now seven years old and have around 1.5 million unique visitors per month.

News Archive