The goal of this project is to design a cost effective, 3D printable biocompatible prosthetic foot, capable of facilitating full function with little compromised gait. 3D printing enables the optimization of material properties, to mimic the function of the limb the prosthetic foot is replacing. A study of high school runners led to the analysis of forces that affect movement, and a final design that delivers 124% in kinetic energy transfer and output. This level of potential energy storage resulted in an increased safety factor of 5.52ul, 0.36% variance from a perfect rating of 5.50ul. Applied physics and mathematics were used to quantify the adverse impact of gap co-linear compression and its effect on material properties and structural integrity. Tests involving complex cantilever beams utilized differential equations to compare stress, strain modulus, and compressive strength. This led to the development of two equations to calculate discrepancies between ASTM standards and each 3D printed part, where the discrepancies resulted from the gap co-linear compression. Graphical analysis confirmed biocompatibility associated with a level 4 prosthetic, with 5.3% compromised gait, capable of sustained intensive movement. The 3D printed Nylon 6/6 design can be easily scaled, redesigned and reprinted as needed to accommodate human growth. Each reprinting will cost no more than $23 in materials, compared to the $18,000 it costs to replace a standard prosthetic foot. The result is an affordable, 3D printable prosthetic foot that exceeds basic ambulation capability and allows active adult function for a fraction of the cost.

What inspired you (or your team)?

I wanted to help the developing world. I came across a picture of a little Congolese girl who had suffered a forced foot amputation after Bosco Ntaganda and his child soldiers raided her village. This stuck with me and I conducted research on why the “prosthetics” she had were so rudimentary. After realizing that lower limb prosthetics are the most common type of amputation and that they are also prohibitively expensive I found the basis for my project. I did not know much about rapid prototyping at the time but just a couple of days later my high school purchased a new 3D printer. Naturally I had to know about the cool new gadget in my classroom, so I looked up “Ultimate”, the brand of the 3D printer at the school. On the front page of their website was a short documentary about 3D printing engineers who paired with prosthetists visiting Haiti who were fitting children with cheap 3D printed prosthetics. I felt the need to design a biocompatible prosthetic that could change a child’s life to give them the basic function I take for granted every day.