Seeking 3D-Printable Wrist-Controlled Prosthetic Hand Mechanisms

[JudahMarchiondo@tdss]

I am developing a 3D-printed prosthetic hand intended for individuals who have wrist movement but are missing their hand. The mechanism must be controlled entirely by wrist motion, without reliance on electronics or external power sources.

The design needs to be durable, functional, and easy to assemble, as it will be used in a donation-based setting where long-term reliability is critical. The goal is to create a fully 3D-printable solution that minimizes the need for additional non-printed components.

Challenges:

• Developing a wrist-driven mechanism that provides a secure and consistent grip.
• Ensuring durability for daily use while maintaining ease of assembly.
• Avoiding fast-wearing components such as rubber bands or fragile joints.
• Keeping the design as simple and accessible as possible without compromising function.

I am not looking for a full design, but rather recommendations on mechanisms, linkages, or structural approaches that would be most effective for this type of prosthetic. Additionally, if there are material choices that significantly improve long-term performance, I would appreciate any insights.

Any guidance from those experienced in prosthetic development or mechanical design would be greatly valued.

 

[MintJulep]

I guess you might start by quantifying what wrist motion is.

 

[JudahMarchiondo@tdss]

Thank you for your response — that’s a great point. By quantifying wrist motion, I’m referring to the types and ranges of movement the wrist can provide: flexion, extension, radial deviation, and ulnar deviation.

One approach I’m considering is using a tension-based linkage system, where wrist flexion or extension tightens a cable to close the fingers, and relaxing it opens them. This could be similar to how body-powered prosthetics use shoulder movement, but scaled down for the wrist. The challenge is finding a way to ensure the grip is strong and consistent without relying on elastic materials that degrade over time.

 

[MintJulep]

Ok.
Next, quantify the force and displacement possible from each of those motions.
Then define what your can react the forces against.