Mechanical Prosthetic

In my final year of my Mechanical Engineering bachelors, my team decided to build a fully mechanical prosthetic finger geared towards full finger loss. 

Mechanical Finger Prosthetic Design: 

Fully mechanically operated prosthetic finger. The finger is actuated using body powered movements. 

Design Scope and Goals:

• Same level of functionality as electromechanical prosthetics

• Combines string actuated and ratcheting prosthetics

• 3D printed for accessibility and low cost

• integrated pawl lock to 

Print Settings:

PETG Temps: Hotend: 240 C, Bed: 85 C 

Socket, Medial Phalange, Distal Phalange: 

• 20% gyroid infill, organic support

Proximal Phalange, Pawl, Pawl Lock: Potentially 0.1 mm layer width

• 40% gyroid infill, organic support, 4 perimeter layers

Optional: 

Linkages:

• 40% gyroid infill

Fishing Line: 

3 Main Kinds: monofilament 

Monofilament - lots of stretch, floating property, wears out quicker, less memory

Flourocarbon - more dense, will sink, abrasion resistant, lower stretch, high memory

Braided - lowest stretch, floating property, moderate abrasive resistant

I went with braided as DangerCreations chose braided fishing line for his prosthetic finger. It has the lowest stretch compared to other fishing line and is rated for 130 lbs of force. The string has a diameter of 0.63 mm, which is perfect for my application.