Two years ago, Anna Grimaldi, a Paralympic gold-winning athlete from New Zealand, felt that she had hit a wall with her training. Born without a right hand, she had been using a prosthetic to help her grip gym equipment. But it was difficult to find something suitable at her local prosthetics center; the prosthetic that fit her best was actually designed for children, and it was created for everyday activities like picking up a shopping bag, not for holding the 300-plus-pound weights she was lifting at the gym. Her teammate, javelin thrower Holly Robinson, felt similarly: She couldn’t find a prosthetic that felt safe for exercise. Both were frustrated: They were world-class athletes forced to train at less than their full capacity, at risk of competing at a disadvantage just because they couldn’t train the way they wanted.
Dr. Stafford Murray, the head of innovation at the government-funded High Performance Sport New Zealand (HPSNZ), heard Robinson mention this at a conference. And when he talked to her afterward, he became determined to find a solution for her and Grimaldi.
That’s why Murray, the athletes, and 3D printing and engineering firm Zenith Tecnica, with machine and technical support from GE Additive, came together: to design and make a new kind of prosthetic that could be tailored to each athlete’s needs. And the result shows that metal 3D printing, or additive manufacturing—with its applications in aerospace, marine vessels, and more—is a solution that also can scale out from an individual level. By virtue of the speed of its process and the strength of its products, it was an ideal solution for these two athletes. In the future, it could be a solution for thousands more.
The process was a holistic collaboration—from the users of the end products to the people working the machines that made them.
Anna Grimaldi is a Paralympic long jumper from New Zealand and the recipient of a new prosthetic arm created with additive manufacturing technology.
Grimaldi says that with her previous prosthetic, “There was always sort of a disconnect with whatever I was holding.” But when she tried the new prosthetic for the first time, she says, “I was quite shocked at how good it had turned out. I just felt like I was finally fully in charge.”
She feels both stronger and safer by training with the customized limb. “[My old prosthetic] wobbled around everywhere,” Grimaldi says. “Now I’ve got one that clamps on, that I can do dead lifts with. It’s allowed us a lot more stability; I never thought that having the arm attached to something would make such a big difference, but it has.”
Robinson, too, has been able to improve her strength and throw new personal bests with the javelin. “The 3D printing allowed it to be super specific to each of us,” Grimaldi points out.
The Prosthetic
Duncan Anderson, an engineer, and Dr. Stafford Murray, head of innovation, both work at High Performance Sport New Zealand. They designed the prosthetic limbs given to Anna and Holly.
To Anderson, the engineer who designed the prosthetics, it was apparent early on that the only way to produce what Grimaldi and Robinson needed was through additive manufacturing. “A large part of this project was understanding the human nature of it. It was really valuable to meet with the end user and assess their level of mobility,” he says. “I could see that the parts were going to be extremely complicated and small, with lots of curved surfaces and complicated geometry, which in a conventional machine would be complicated to achieve.”
“Duncan stripped it to the basics and said, ‘This is an engineering problem,’” says Dr. Murray. “We had to make it adaptable and agile and the same weight and length as the girls’ nondisabled arm so there was parity and synergy across both arms.”
The Computer-Aided Design
Pete Sefont, production manager at 3D printing company Zenith Tecnica, oversaw the manufacturing of the prosthetic limbs designed by Anderson and Murray.
At Zenith Tecnica, Sefont was in charge of ensuring that Anderson’s designs yielded a functional end product. “The goal was to make the limbs as light as possible so [the athletes] notice it as little as possible,” he says. “That’s the magic of Duncan’s design.”
The process used by Zenith Tecnica, electron beam melting (EBM), is an incredibly precise form of additive manufacturing. GE Additive’s EBM machines read a digital schematic and interpret it in layers of titanium powder that are melted and fused together by an electron beam, rendering many traditional manufacturing processes obsolete. “There’s no tooling,” Sefont says, meaning there’s no need to source and combine various physical parts or mechanisms. “We’re building straight from titanium powder. As a result, we’re able to mass customize our components.”
The Material
Maria Öström is a medical product manager at GE Additive, the company that makes the 3D printing machines used at Zenith Tecnica.
To create both the prototype prosthetic limbs and the final titanium product, Zenith Tecnica used Arcam EBM machines built by GE Additive. Öström has seen how their EBM technology has enabled manufacturing that would otherwise require significantly more resources and time.
“GE, in-house, has a whole solution,” Öström says. “Anywhere from the [titanium] powder…to having three really strong technologies in EBM, direct metal laser melting (DMLM), and binder jet, and helping our customers pick the solutions that are suitable for their type of application.”
She’s been proud to see how Zenith Tecnica uses those GE Additive solutions. “They’re a customer that really sees the possibilities,” she says. “I’m really passionate about seeing new products and making sure they actually reach people to help their lives.”
The 3D Printer
Additive manufacturing is what made these prosthetics possible—and it could also enable customized prosthetics for everyone who needs one.
Every team who played a role in the development of these new prosthetics—from the athletes to the engineers—has seen firsthand how additive manufacturing made them possible. They’ve also seen how the prosthetics have empowered Grimaldi and Robinson to train without inhibitions. “I’ve been involved with Olympic sports for nearly 25 years,” Murray says. “It’s probably the most satisfying thing I’ve ever seen. Anna and Holly could train the same as athletes without a disability. With this 3D printed attachment, their disability is basically out of the equation.”
While this specific application was for world-class athletes, Grimaldi points out that the low cost and the efficiency that additive manufacturing brought to the process could allow this kind of prosthetic to reach anyone with a disability. “You wouldn’t even have to be an athlete to feel like this is awesome,” she adds. “It would be a cool tool for anyone missing a hand. I hope one day that [3D printed prosthetics] will be available for whoever.”
To take Grimaldi’s point even further, every industry that involves manufacturing could benefit from the speed, the low cost, and the granularity enabled by the additive process. From massive, complex machinery up in space to miniscule medical implants, the things that additive manufacturing can create are part of a new industrial revolution.
