From Prototype to Patient
How Aether Biomedical built a stronger bionic hand with Carbon
The Challenge
As mechanical devices are used constantly for everyday tasks, prosthetic hands are prone to wear and breakage. When they do break, traditional repair can take four to six weeks, often because the device has to be shipped away for service. For Aether Biomedical, a fast-growing prosthetics company, that gap was central to the problem they set out to solve: build a bionic hand that is not just strong, but modular and field-repairable, so a break doesn’t mean weeks without a working hand.
As a small, fast-moving company, Aether also needed a manufacturing approach that gave them design flexibility and a low barrier to entry. The prosthetics market is low-volume and high-value, so their production model had to fit that reality rather than the high-volume assumptions behind most traditional manufacturing processes.
The Solution: A Material Journey
Version 1: Built on Multi-Jet Fusion
Aether’s first-generation Zeus hand was built using multi-jet fusion (MJF) 3D printing. MJF fit the hand’s original 15mm motors well on both accuracy and wall thickness, and as a young company without capital for injection-mold tooling, or a finalized design, 3D printing let Aether iterate 20-plus times per component with no tooling cost. The result was a hand with high grip strength, but larger than the market wanted.
Outgrowing the First Material
As Aether moved to a second-generation hand, they wanted to deliver what the market asked for: a smaller device with the same strength they’d become known for. That meant smaller 12mm motors and thinner walls, down to roughly 1mm. This is where MJF began to reach its limits. MJF materials were too brittle at that thickness, and its tolerances were far looser than what was required. In practice, that meant Aether’s team had to manually rework nearly every part to get it to fit, an approach that worked for prototyping but didn’t scale to repeatable, high-volume manufacturing.
Finding RPU 130
Aether needed a single material that delivered precision, repeatability, thin-wall strength, and impact resistance all at once, a combination few materials or manufacturing processes offer together. Injection molding was ruled out because the hand’s organic, cavity-rich geometry doesn’t mold well. After evaluating multiple resins and processes, RPU 130, part of Carbon’s platform, stood out as the most production-ready fit, offering tight tolerances with no tooling investment.
Why RPU 130 Was the Right Fit
As they evaluated options, Aether Biomedical found that most materials they looked at cleared only two of three requirements that mattered for the redesigned hand: enough strength to preserve the hand’s high grip performance, enough impact resistance to avoid brittleness, and the ability to actually be printed at very thin wall thickness. RPU 130 was the rare material that cleared all three at once.
“It’s flexible enough to allow us to transmit the impacts that our hand is subjected to… and the tensile strength is also good enough. Combining that with the impact resistance, it’s the perfect material out of 3D printing that we could choose that allows for very high detail precision.”
Rafal Pilaczynski, Head of Production, Aether Biomedical
RPU 130 is used throughout the Zeus V2 hand’s finger phalanges and the distal thumb. Underlying that performance is Carbon’s dual-cure chemistry: UV light rapidly cures the part into shape, and a subsequent thermal bake completes an interpenetrating polymer network. Because the process doesn’t build parts up in discrete layers the way conventional 3D printing does, RPU 130 parts perform consistently in every direction rather than only along the print axis, with an impact resistance of 76 J/m and a heat deflection temperature of 119Ā°C, performance in the range of ABS, PEEK, PSU, and nylon.
Manufacturing at Scale
Moving from prototype to production also meant rethinking how Aether manufactured the volumes they needed. Because Carbon’s process requires no tooling investment, Aether has been able to validate designs in small batches without a steep cost penalty. That also means Aether can keep iterating the design right up until production without a re-tooling bill each time.
Tolerances tight enough for near plug-and-play assembly removed another bottleneck: the manual rework Aether’s team once needed to fit MJF parts together. That shift, from reworking nearly every part by hand to assembling parts straight off the shelf, was central to scaling Aether’s own production from roughly 5 to 10 units a month to over 100 units a month, thousands of units a year, without sacrificing the consistency a regulated medical device requires.
“This technology, we basically don’t touch the part at all, we just pull them from the shelf and fit them in place. It’s a plug-and-play kind of fit, much closer to a streamlined production line.”
Rafal Pilaczynski, Head of Production, Aether Biomedical
The Results
| 30 MIN | 100+/month | ~ 1mm |
|---|---|---|
| FIELD REPAIR TIME, DOWN FROM 4-6 WEEKS | PRODUCTION VOLUME, UP FROM 5-10/MO | WALL THICKNESS ACHIEVED |
The most visible result is repair time. Carbon’s process gave Aether the design freedom to build a modular hand, and that modular design cut repair time significantly. With a field-repairable design, users are able to cut repair time from four to six weeks down to a 30 minute visit to a clinician.
“We chose Carbon because we were a small company that required flexibility in iterations, designs, and a low barrier to entry into the market. On top of that, prosthetic hands break a lot, and it takes 4 to 6 weeks to get them repaired. Our hands can be repaired in less than 30 minutes by a clinician in the field, because the design is modular.”
Dhruv Agrawal, CEO, Aether Biomedical
Looking Ahead
Aether Biomedical continues to refine the Zeus hand’s design on a stable additive manufacturing process and cost base, iterating on materials and geometry without the constraints that come with tooling manufacturing. For a company built on the promise of getting patients back to their lives faster, that ongoing flexibility, as much as any single material or spec, is the point.
