Hello, I am making a 3D printable infant prosthesis, and need tiny valve designs such as, ball, rotary, solenoid, etc. great examples of which can be found here: basics-of-hydraulic-directional-control-valves . It is a daunting task for the designer, tubing lengths, valves, pump pressure etc.
Ideally the hand needs to achieve about 20 different positions to be any good. Interestingly, the Thumb works like a separate limb altogether.
But, needs combining with the four fingers, with regards to the tubing, valves, and pressure formulas in order to make an effective, Arduino controlled system. The Pump position, can be at the start of the wrist, forearm, or top arm, but, for now I am concentrating the design, on just the Hand. The Shoulder joint, is the same as the Wrist joint, Hip joint, Ankle joint and interestingly the Index finger joint [small motors needed here] esp. as my prototype design is for a 2 year old infant. I am going to make tiny 3D printable valves, for this project. Any useful design considerations, for a tubing setup etc, as outlined above, would be most welcome! - purely charitable and humanitarian attempt.

 

Ammendment to above: Hello, I am making a 3D printable infant prosthesis, and need tiny valve designs such as, ball, rotary, solenoid, etc. great examples of which can be found here: basics-of-hydraulic-directional-control-valves . It is a daunting task for the designer, tubing lengths, valves, pump pressure etc. inflatable infant prosthesis design Relying on the nature of how air pressure works in controlled pre-filled air inflatable, against a small amount of spring tension at each joint, enough for a baby or small child. Inflating lozenge shapes, actuate valve handles, to fill air chambers in the fingers, which work against small spring tension, to return the hand to a relaxed position. Deflation, allows the spring to close fully, like a fist. Hopefully, fully 3D printable springs, lozenges, valves, inner main rotating finger structure, outer shell, and life like, skin stretchy, skin textured outer 3D skin! Ideally the hand needs to achieve about 20 different positions to be any good. Interestingly, the Thumb works like a separate limb altogether.
But, needs combining with the four fingers, with regards to the tubing, valves, and pressure formulas in order to make an effective, Arduino controlled system. The Pump position, can be at the start of the wrist, forearm, or top arm, but, for now I am concentrating the design, on just the Hand. The Shoulder joint, is the same as the Wrist joint, Hip joint, Ankle joint and interestingly the Index finger joint [small motors needed here] esp. as my prototype design is for a 2 year old infant. I am going to make tiny 3D printable valves, for this project. Any useful design considerations, for a tubing setup etc, as outlined above, would be most welcome! - purely charitable and humanitarian attempt.

 

This is a fantastic humanitarian project. For your infant prosthesis, here are some key design tips:

• Valves: Instead of ball/rotary, try reed or flap valves—easier to 3D print at small scale. Consider TPU for flexible, airtight parts.
• Tubing: Keep runs short, use a manifold for even airflow.
• Air Chambers: TPU “lozenge” bladders pre-filled slightly reduce pump demand.
• Springs: 3D printed springs fatigue quickly—TPU bands or hybrid designs work better.
• Control: Start simple with inflate/deflate per finger, add PWM or proportional valves later. Include pressure sensors for safety.
• Pump Placement: Keep in the forearm/upper arm to reduce hand weight.

Prototype with 1–2 fingers first, then scale up. This stepwise approach helps balance safety, simplicity, and functionality.