Beautiful 3D printed prosthetics
LOSING A LIMB IS A TRAUMATIC and life-changing experience and, for many, the cost of a traditional prosthetic replacement, ranging from about US$3,000 to US$30,000 for an arm and about US$5,000 to US$50,000 for a leg, is just too expensive to be a feasible option. But today, advancements in 3D printing may offer an alternative solution at a fraction of the cost. Many amputees have already benefited from open-source schematics for 3D printed prosthetics that are readily available online. e-Nable, a global network of volunteers helps supply amputees with these 3D printed limbs, which often cost just less than US$50 to make. But while these low-cost 3D printed limbs are affordable, they also have their own drawbacks. Due to the generic nature of the schematic, the socket fitting is often mediocre and uncomfortable, and the plastic used in the 3D printing process isn’t as durable or capable of supporting as much weight as the high-quality polymers and metals used in traditional prosthetics. In addition, they often look and feel unaesthetic, which can exacerbate the sense of loss and negatively affect the psychological wellbeing of some amputees. One New York-based designer is trying to change all of that. By using a combination of 3D scanning, 3D printing and 3D modeling software, William Root’s ExoProsthetic leg is not only affordable to make, it’s also fully customizable, super strong, super light, and it looks amazing. The process begins with a scan of the patient’s residual limb and remaining intact limb, if present, to create a highly precise 3D virtual model, allowing the anatomy to match up to within fractions of a millimeter. This process is done with a technology developed by MIT’s Biomechatronics lab called FitSocket, which uses an array of pressure sensors to gauge the softness or stiffness of a patient’s remaining tissue, allowing for a better fit and increased comfort between the residual limb and socket. Using the same data, Root then extrapolates a 3D model of the patient’s full limb, which is turned into a triangulated mesh. Root has designed a hollowed out exoskeleton model that he says offers “maximum strength for the least amount of material and weight”. A stress analysis tool helps determine weak-points on the model, and software increases the mesh density of the structure to compensate. The surface pattern of the exoskeleton can be customized with patterns and colors to suit the client, or it can later be used as a scaffolding for a lifelike silicone sleeve. The finished model is sent to an industrial 3D printer and printed out of sintered titanium powder, an extremely durable, lightweight and biocompatible metal. The process fuses titanium dust particles together using laser sintering. Printed as a single 3D exoskeleton it is immediately ready for assembly. Using custom connectors 3D printed directly onto the prosthesis, off-the-shelf prosthetic components are inserted into the Exo leg, and it is securely assembled using a standard pyramid connector. The result is a prosthetic limb that looks like it came straight out of a sci-fi movie or video game. According to Root, the total cost from scan to finished product is about US$1,800. Now Root is considering how best to apply his process to existing systems, and whether it would be most effective being taken up by a startup, a 3D-printing company or a big player in the existing prosthesis marketplace.
“BY USING A COMBINATION OF 3D SCANNING, 3D PRINTING AND 3D MODELING SOFTWARE, WILLIAM ROOT’S EXO-PROSTHETIC LEG IS NOT ONLY AFFORDABLE TO MAKE, IT’S ALSO
FULLY CUSTOMIZABLE, SUPER STRONG, SUPER LIGHT, AND IT LOOKS AMAZING.”