Two-year-old Sol with his fully-functioning Stratasys 3D printed hydraulic prosthetic arm, which enables him to move his thumb on his own. [Image from BusinessWire]
The prosthetic was designed for Ambionics’ founder Ben Ryan’s 2-year-old son, enabling a more natural acceptance of prosthetics for children.
So far, the 3D-printed hydraulic prosthetic has delivered 76% cost savings and 90% time savings in design and production.
Ryan’s son had complications in his arm that resulted in the amputation of his lower left arm, leaving 1 in. left on his lower arm. Doctors told him he would have to wait 3 years to be fitted for a myoelectric prosthetic through the National Health Service in the U.K. and 1 year for a cosmetic, nonfictional prosthetic. His son was eventually losing responsiveness and acceptance of his arm.
Using Stratasys’ Connex 3D printer, Ryan 3D printed flexible actuators and a power-splitting unit for the hydraulic prosthetic. The double acting helical bellow (DAHB) in the power-splitting unit allows the prosthetic wearer to open and close the thumb of the prosthetic in manual mode or using an assistive power like compressed air or a hydraulic pump and reservoir. The grip can operate manually if there is a power interruption.
“The success of my patented DAHB mechanism draws on the advanced capabilities of the Stratasys Connex Printer – the ability to combine rigid and soft materials in a single print was vital to the success of the design,” said Ryan in a press release. “We were fortunate enough to have access to this technology, which enabled us to 3D print a prototype arm so quickly and cost-effectively. In founding Ambionics, it’s now my goal to ensure that other limb deficient children like my son are not faced with the current constraints and delays of traditional prosthetic manufacture.”
Ryan also used Autodesk Fusion 360 to design the prosthetic.
The prosthetic arm weighs less than a traditional myoelectric prosthetic and is body-powered while allowing infants to grow to like their new arm sooner than traditional prosthetics. Since the Ambionics-developed prosthetic arm can operate without electricity, the risk of injury is eliminated.
In 5 days time, the prosthetic arm can be produced using digital copies that also allows for it to be easily replaced through 3D printing.
“Essentially, the entire prosthetic is 3D printed,” said Ryan. “Only Stratasys’ strong rubber-like and dissolvable support 3D printing materials make production and use of the DAHB units possible. The internal cavities are complex and it would be impossible to remove the support material using mechanical means. The materials must also be strong yet flexible as they are used to transmit fluid pressure to operate the grip.”
Ambionics hopes to be able to offer the patented DAHB technology worldwide and is continuing its research and testing for infant development with prosthetics.
“This case is indicative of 3D printing’s ability to improve lives by overcoming the traditional barriers of low-volume manufacturing,” said Scott Vader, general manager of healthcare solutions at Stratasys. “We continue to support and enable innovators like Ben to bring customization to mainstream prosthetics manufacture.”
