Merrimack students create prosthetic Bat Hand with 3-D printer for a 12-year-old

A group of Merrimack students delivered a prosthetic hand they helped make to a 12-year-old St. Louis-area boy during winter break.
Merrimack News

Joe Fairley, a graduate fellow in the Exercise and Sports Science master’s degree program, led the group.

“It’s a heartwarming experience,” Fairley said after returning to campus. “You realize after the fact you’re impacting a person’s life for the better.”

Fairley delivered the hand and fitted it with Ashley Widing ’17, of Charlton, Mass., and Samantha Monaco ’18, of Brewster, N.Y. The boy is a Batman fan so Fairley’s team modeled the hand after the caped crusader.

Fairley and the Merrimack chapter of e-NABLE built the hand using a 3-D printer in the School of Science and Engineering, and are now committed to making at least five hands to contribute to a project in Budapest, Hungary that’s collecting 50 prosthetics for shipment to Ghana.

Bailey, the St. Louis-area boy, was the third person Fairley has helped.

The first hand was made while Fairley was still an undergraduate at Siena College in Loudonville, N.Y. Allan Weatherwax, dean of Merrimack’s School of Science and Engineering, was a professor and dean of Siena’s School of Science when he introduced Fairley to the school’s new 3-D printer. Fairley, of Saratoga Springs, N.Y. was an engineering major and already knew he wanted to work with prosthetics so he looked for ways to use the printer.

He started by trying to modify the arm of a robot developed and built with a 3-D printer in France but after a month of work learned about the fledgling e-NABLE group. e-NABLE is an affiliation of volunteers from around the world using 3-D printers to make prosthetic hands and Fairley proposed opening the first collegiate chapter at Siena. He’s now helping codify the rules for colleges so about 12 more schools can open chapters.

The first hand Fairley helped build with a 3-D printer had an Ironman motif for a then-5-year-old boy in Columbus.

Fairley and his e-NABLE chapter at Siena followed that up with a prosthetic hand for a man in New Orleans last April.

When Weatherwax was named Merrimack’s dean, Fairley decided to apply for the master’s degree program in North Andover.

When he arrived, Fairley founded the Merrimack chapter of e-NABLE. There are about 20 core members working in teams on projects needed to complete and deliver the prosthetics. They include CAD design, assembly, social media, financing, and clinical follow-up. Each team meets at least once a week and the entire chapter meets a couple times a week during the semester.

It takes about 20 hours for one of the school’s 3-D printers to make the parts which then have to be assembled using kits that are purchased with screws, cables, tensioners, padding and Velcro included.

Fairley is spending the rest of his break between semesters working on a prototype prosthetic leg for a 2-year-old New Orleans-area boy. The leg is cutting edge, even for 3-D printers because of the strain and pounding it must withstand. He’s had a couple of breakthroughs on the design and is hoping to have the draft drawn up by springtime.

“I’ve always had high ambitions and always had a knack for inventing something or coming up with the next-best thing,” said Fairley said.

The prosthetic hands close into a fist when the user bends their wrist, and can lift light objects or turn a doorknob. The prosthetic hand is more cosmetic than anything else right now but ongoing improvements will make it more practical over time, Fairley said. Prosthetic hands from 3-D printers date to at least the 1980s but have made great strides in just the last few years, he said.

State-of-the art prosthetic hands are rare for children. They can cost thousands of dollars and then the children grow out of them quickly. The 3-D printer versions cost as little as $30 to $50 to make, depending on the assembly kit used, Fairley said.

Bailey, the St. Louis-area boy, was born without three fingers on his left hand but has a thumb and pinky up to the first knuckle so he’s able to pinch objects to pick them up.

Fairley made Bailey a prosthetic hand when Bailey was 10 years old but he outgrew it and it broke along the way. So this time Fairley decided to use the Raptor Reloaded design provided by e-NABLE instead of the previously used Cyborg Beast model. The Raptor has more fluid movement of joints with two hinges for stability compared to the single-hinge Cyborg, which is where Bailey’s first prosthetic broke, Fairley said.

Fairley and his team modified the CAD file to eliminate the thumb and pinky on the Raptor Reloaded so Bailey can still pinch objects.

Fairley’s ambitions are hardly fulfilled. He wants to develop a clinical follow-up program with e-NABLE. Once the prosthetic hands are delivered there isn’t a follow-up program to learn how they are working and fitting.

“The follow-up is actually my capstone project I’ll be finishing up in the spring,” Fairley said.

He’s created two surveys for recipients.

The first will be completed before the hand is delivered, asking the recipient’s expectations  and how they plan to use the hand, so it can be designed to match their needs.

The follow-up survey will be completed about a month after delivery, asking if the hand is holding up under wear-and-tear and whether it meets expectations.

Core members of Merrimack’s chapter of e-NABLE include Fairley, Widing, Monaco, Chase Tucker ’17, of West Warwick, R.I.; David Bailot ’16, of Adams, Mass.; Mark Zabicki, of Nashua, N.H.; Brittany Razo ’16, of Anaheim, Calif.; Stephen Ribero, of Londonderry N.H.; Cara Cole, of Norwood, Mass.; Danielle Miles, of Wilmington, Mass.; and Gabriella Trahant, of Lynn, Mass.; and Kelly Hurley ’17, of Burlington, Mass.

To view a video of Fairley explaining the process of building an e-NABLE prosthetic hand visit



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