The custom-fit thumb shell is produced by digitally scanning the user’s hand and refining the digital model in Autodesk Meshmixer and SolidWorks for FDM printing in TPU 95A, a flexible, resilient filament with prototype material costs under $5. The design minimizes plastic coverage on the palm to preserve residual sensation, fixes the distal phalanx at a 45° flexion angle to enable natural opposition, and integrates a compressible fingertip section to enhance grasp. Rapid prototyping and ready-to-print generic sizing options allow quick iteration across different hand geometries, and open-access design files support further tailoring for partial-hand users or the addition of moving parts.
Description
Compared to conventional prosthetic thumbs that often use rigid PLA or ABS plastics and incur significantly higher costs, this approach leverages the elasticity and durability of TPU 95A to offer improved comfort and functionality at a fraction of the price. Digital scanning ensures an accurate, personalized fit, while minimal coverage preserves sensory feedback often lost in traditional devices. The fixed flexion angle and compressible tip facilitate immediate functional use without complex assembly, and the open-source framework combined with low material costs accelerates accessibility and customization for thousands of traumatic thumb amputees lacking affordable, functional alternatives.
Applications
- Custom 3D-printed prosthetics
- Low-cost thumb prostheses
- Rapid prosthetic prototyping
- Open-access prosthetic kits
- Flexible TPU prosthetic components
Advantages
- Low material cost (under $5 per prototype) enabling affordable production
- Custom-fit design via digital scanning and CAD ensuring comfort and precise fit
- Flexible TPU 95A filament for durability and natural movement
- Minimal palm coverage preserving residual sensation
- Fixed 45° flexion angle to facilitate thumb opposition and functional grasp
- Compressible fingertip section enhancing object grip
- Rapid prototyping enabling quick iteration and refinement
- Generic sizing options reducing delivery and adaptation time
- Open‐access design files supporting further customization and community improvements
