Single-Step 3D Printing of Bio-Inspired Printable Joints Applied to a Prosthetic Hand

Area of Science:

• Biomimetics and Robotics
• Additive Manufacturing
• Prosthetics Design

Background:

• Current 3D printing struggles with precision for movable parts, requiring gaps that limit mechanism accuracy.
• Existing prosthetic designs often involve complex assembly and higher costs.

Purpose of the Study:

• To introduce a bio-inspired printable joint for single-step 3D printing of functional mechanisms.
• To apply this joint to create a precise, low-cost, and easily assembled prosthetic hand.

Main Methods:

• Simulating human finger joint anatomy to create a bio-inspired printable joint.
• Implementing a cam effect using elastic bending for precise joint motion.
• Integrating the joint into a monolithic structure for a Single sTep 3D-printed Prosthetic hand (ST3P hand).

Main Results:

• The ST3P hand is a lightweight (∼255g), low-cost (∼$500) monolithic structure with nine precise finger joints.
• Assembly time is significantly reduced to ∼6 minutes, one-tenth of comparable prostheses.
• The hand demonstrates functional capabilities with a pulling force of 48 N and grasp strength of 20 N.

Conclusions:

• The bio-inspired printable joint facilitates single-step 3D printing of precise, movable mechanisms.
• The ST3P hand offers a practical, cost-effective solution for customized robotic prosthetics.
• This advancement moves closer to accessible, high-performance prosthetic solutions.