AMS Spring 2023

exiii Offers Lineup of Affordable 3D Printed Robotic Prosthetics, Including Open-Source HACKberry


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exiiirogoAs the world of 3D printing technology evolves faster than most can keep up with, the impacts it offers to humans in need are powerful, life-changing, and deeply inspiring. The days of having a prosthetic and feeling ashamed or embarrassed are quickly fading as these medical devices are becoming both a triumph in themselves and for those wearing them—and often, showing them off.

And when it comes to one trio of smart young engineers in Japan, they are using 3D printing to take prosthetic hands directly into the future. For them, it all began with a small boy’s love for basketball and a fascination with the way the hand was truly the center of the game, employing so much of the lower arm and fingers to use the ball skillfully and work on winning the game.

Genta Kondo grew up and went on to work for Sony in Tokyo, where he became proficient in the world of robotics. 3D printing came into the mix with his work and from there, the spark of an idea for exiii was born.

“I’ve always been fascinated with the hand, and what makes it move. I’ve been playing basketball since I was a kid, and the subtle movements of the hand for passing and shooting really appealed to me. When you think about it, the hands are like a ‘second brain,’ a vessel we use for so many forms of expression, whether it be sports, music, cooking, or something else. So my interest in the hand was really the starting point for everything since,” Genta Kondo explained to

With his growing experience in 3D printing and prototyping, Kondo’s passion for the intrinsic mechanics of the human hand were reignited as he collaborated with his friend Hiroshi Yamaura, a mechanical engineer at Panasonic in Osaka. Yamaura was already producing 3D printed hand models on his consumer 3D printer. As they began discussing the idea of robotic hands, Tetsuya Konishi, an industrial designer at Panasonic, also joined forces with them.

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[Photo courtesy of exiii, Inc.]

Together, they began working on the idea of a myoelectric prosthetic hand which would be battery powered, and revolutionary in that the electric signals would be generated in a natural manner, from the wearer’s muscles. The way that the first prototype was created was very impressive, with the team communicating from 250 miles between them—and that very piece went on to win recognition in the James Dyson Awards and in so doing, the team gained their first supporter by way of Akira Morikawa who is missing an arm and became a big supporter. He was also the impetus for the founding of the exiii startup in 2014.

And with that beginning, they put all the benefits of 3D printing to use, for the good of physically challenged individuals everywhere. Looking at all the features they could offer with their robotic prosthetics, they realized it could be done for $300 per device. That’s a stunning difference from the traditional $15,000 or so that a patient would normally be required—and often unable—to pay.

“Before thinking about whether or not to start this project, I had an issue with the current state of engineers at large corporations. I like to create things, but manufacturing consumer products at large corporations involves too many people, making it difficult to get my own thoughts or ideas implemented in many cases. I felt that it might be impossible to create the things I really wanted to create in a place like that,” Hiroshi Yamaura told

Thanks to the power of 3D printing, they began fabricating streamlined, affordable pieces that are simple and highly functional. The team is able to make them easily as well as customizing them, which is most important. They already have a lineup of three different products as well:

handiii – this model actually uses a smartphone to collect muscle signals, and is constructed with six motors. 3D printed, it is easy to customize, maintain, and fix, and the user is able to choose the color, texture, and function.

handiii Coyote – this model offers a universal socket to be customized to the user’s arm length and size, and functions with a lithium battery offering two to three hours of use at a time.

HACKberry – this is a more compact model that focuses on the ‘pinch grip.’ It features three motors and uses rechargeable digital camera batteries. It’s important to note also, that this model has been released as an open-source design so that anyone interested can make one. The company’s open source software and plans are available on its website, and it provides assembly instructions with YouTube videos.

“The prosthetic hands we make are nothing like actual human hands. They’re more like industrial products. Up to now, prosthetic hands have always been designed to hide the fact that you’re missing a hand. But we want Exiii prosthetics to be a channel for self-expression. For example, just like with watches or shoes, we want our prosthetics to be something users can wear as everyday products, to actually have fun with by choosing a specific design to suit their own fashion tastes,” Tetsuya Konishi told us.

The 3D printed handiii [Photo courtesy of exiii, Inc.]

The HACKberry design has been popular with the open-source platform, and the team has shared that one man in Poland was able to use the design to make a 3D printed child’s left-handed prosthetic for a friend’s son.

“Our original intention for going open source was to speed up the development process. With only the three of us, it would take a lot of time to get our prosthetic hand to where it could actually be used, no matter how much effort we poured into it. I feel like we’ve sparked this amazing network of users, branching out in various directions,” said Yamaura in a recent Autodesk article.

And it’s only logical that a bright young group like this would be working on going above and beyond just prosthetic designs for the hand, along with Autodesk’s 3D printing technology.

“If we were planning to specialize in prosthetic hands and nothing else, we probably would have called the company ‘handiii,’” says Kondo. “But we separated the product name from the company name, because our vision is to ‘bring joy to everyday life through robotics and design.’”

As the team expands their company, they look forward to working with the making community and helping them to develop their own products, empowering them to create and design whether they are artists or engineers—or not. The exiii team has a strong focus on allowing the power of 3D printing to offer independence to anyone who has an idea they’d like to bring to fruition.

“We live in a great era for those who want to create. All of the required infrastructure is available now, including 3D printers and Autodesk products,” says Kondo. “I’d like to see a society in which people who aren’t designers or engineers are able to recognize problems and solve them by creating products themselves.”

What do you think of these unique devices? Discuss in the exiii 3D Printed Prosthetics forum over at

[Source: Autodesk]
exiii 1

[Photo courtesy of exiii, Inc.]

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