FlexSpring 3D Printable Prosthetic Foot 3D Printable
FlexSpring 3D Printable Prosthetic Foot
3D Printable Prosthetic Foot Using CAD and Topology Optimization
Fall 2022
Engineering, Plastic Parts, Generative Design, Topology Optimization, 3D Printing, Prosthetic Design, Bill of Materials, Autodesk Fusion 360, CAD, Force Simulations
New Jersey (NJ)

Allon designed, simulated, and optimized a 3D-printable prosthetic foot using Autodesk Fusion 360, the silhouette of which is based on a 3D model of a woman's foot. Design objectives included for the prosthetic to be plastic, lightweight, strong, able to fit into a sock/pair of cleats (to be soccer-ready), to feature toe flexion, heel cushioning, and ankle flexion, and of course to be 3D printable with off-the-shelf fasteners. Several printable plastics were simulated and it was determined that Nylon (user <123 lbs.), Polycarbonate (user <180 lbs.), and PolyEtherEtherKetone (PEEK) (user <231 lbs.) were the appropriate materials rated for several weights up to around 231 pounds.

The static force/load simulations (SEE BELOW) at first proved the model highly susceptable to deformation/failure which allowed for several design revisions to strengthen joints and overall parts. Allon also experimented with generative design and topology optimization (SEE BELOW) to optimize the geometry of the plastic parts. This resulted in a cheaper, lighter, and potentially stronger assembly (simulation showed no loss in strength/performance). Three prosthetic foot designs were made with decreasing amounts of plastic. Real-world testing is needed to identify simulation shortcomings and test performance.

Allon then created a bill of materials detailing the sources, amounts, and costs of parts needed for assembly including all fasteners and filaments. Below is an animated exploded view of all parts in the final assembly. For an adult woman weighing <180 lbs. with a size 6.5 foot (US), the parts and polycarbonate filament cost an estimated $339.99 with the used material totaling around $173, not including a printer itself.
Topology Optimization of Mid-Foot half considering relevant and extreme loads (SEE VIDEO BELOW)
Final Render of Medium Plastic-Use Iteration
VIDEO: Animated Exploded View, Medium Plastic-Use
Render of the Three Designs with Decreasing Plastic-Use
VIDEO: Toe Static Force Simulation and Topology Optimization Results with Relevant Loads
VIDEO: Mid-Foot Topology Optimization Results with Relevant and Extreme Loads









FlexSpring 3D Printable Prosthetic Foot
Fall 2022
New Jersey (NJ)