RIT Researchers 3D Print Smart Prosthetic Fingers With Multi-Material Construction

Researchers at the Rochester Institute of Technology have built a prosthetic finger system that brings together three disciplines that do not often work on the same part: materials science, sensor engineering, and additive manufacturing. The result is a multi-component finger with a compliant, biocompatible structure, piezoelectric touch sensors, and a custom-designed electromechanical actuation system, all produced with advanced 3D printing processes. The work was published in MDPI's journal on 3D printing and additive manufacturing.

What Makes This Different

Most 3D-printed prosthetics are single-material parts. A hand or finger gets printed in one filament, the electronics are bolted on afterward, and the sensory capability is limited to whatever off-the-shelf sensor can be taped to the surface. The RIT team went further by printing the prosthetic structure itself from a hybrid material combination: a biodegradable thermoplastic for the load-bearing skeleton and a heat-resistant silicone for the compliant outer skin that contacts the outside world.

The sensor layer uses piezoelectric principles, which means it generates a signal when mechanically deformed rather than requiring an external power source to sense contact. That matters for prosthetic design because it reduces the wiring complexity inside a small, moving part. The piezoelectric sensors are capable of resolving different pressure levels, which gives the prosthetic finger a more nuanced sense of touch than a simple on-off contact switch.

How It Was Built

Four faculty members contributed different expertise. Ahasan Habib, assistant professor of mechanical and mechatronics engineering, coordinated the overall system. Krittika Goyal and Jun Han Bae, both assistant professors in the College of Engineering Technology, handled the materials and printing process. Salman Pervaiz, engineering professor and director of materials and advanced manufacturing research at RIT Dubai, led the sensor integration work.

The 3D printing process was chosen specifically to accommodate the multi-material requirement. Traditional manufacturing methods for prosthetic components, including CNC machining and injection molding, are poorly suited to parts that combine rigid and flexible zones in complex geometries. Additive manufacturing allowed the team to print those material transitions in a single build, which is what makes the hybrid construction practical.

What Habib Said About the Design Philosophy

Ahasan Habib put the goal plainly in the published paper: one of the greatest needs in prosthetics is the ability to produce patient-specific devices that match an individual's anatomy, mechanical properties, and functional requirements. Traditional manufacturing methods have limitations in producing complex, customized structures. The RIT approach targets comfort, performance, accessibility, and quality of life for the end user, in that order.

Where This Goes Next

The team produced a working prototype and described it as an affordable, customizable design that can continue to be developed toward commercialization. The electromechanical integration is functional but not yet miniaturized to the point where it could fit inside a cosmetic glove without a visible external housing. That is the next engineering problem to solve, and it is not trivial: smaller actuators, denser wiring, and a power source that fits inside the finger without adding unacceptable weight.

The RIT work is one of several recent academic prosthetic projects using 3D printing, and it sits at an interesting intersection: the materials and sensor technology are closer to what you would find in a research lab than on Amazon, but the design philosophy is aimed at affordability and accessibility, which is what makes the eventual commercial path plausible.