Mechanical Elbow and Human Prosthetic Interface Design

During the entirety of my undergraduate degree, I worked at Limbitless Solutions, a nonprofit dedicated to providing customizable 3D printed prosthetic arms to children at no cost to their families. One of my favorite experiences was developing a novel 3D printed mechanical elbow and an adjustable human-prosthetic interface (HPI) to provide a comfortable and effective suspension system for patients with congenital trans-humeral (above-elbow) amputation. Prior to the implementation of my design, a new interface needed to be measured and built for each patient every few months, but my single elbow/HPI system can accommodate significant growth over several years. While children with extremely short limb remnants often struggle to fit industry-alternative interfaces for their bionic arms, my system is small enough to grip their shorter residual limb and provide a comfortable fit. While there, I implemented my design for four children in the clinical trial, and began expanding its compatibility to patients with trans-radial amputation.

Later, I used Autodesk Moldflow to transition my design from traditional FDM 3D printing to injection molding for mass production. As I utilized dynamometer testing data and Finite Element Analysis, I optimized my designs to minimize material consumption while maximizing strength. Simultaneously, I continued to streamline the HPI system to reduce production cost, as I created standardized templates and protocols for their construction. Ultimately, the implementation of my designs and processes will significantly reduce fitting/manufacturing time and production cost of each device. This experience taught me about user-centric design, as I grew to better empathize with a different demographic while developing scalable, modular products.

In addition to designing the moldable parts, I also created the molds for these designs using Autodesk Inventor. Designed to be milled in-house, I also had the opportunity to learn to design for and generate G-Code for a 3-axis CNC mill.

**Note that some detail is omitted due to intellectual property concerns.