College - Author 1

College of Engineering

Department - Author 1

Biomedical Engineering Department

Degree Name - Author 1

BS in Biomedical Engineering

College - Author 2

College of Engineering

Department - Author 2

Biomedical Engineering Department

Degree - Author 2

BS in Biomedical Engineering

College - Author 3

College of Engineering

Department - Author 3

Biomedical Engineering Department

Degree - Author 3

BS in Biomedical Engineering

Date

3-2020

Primary Advisor

Christopher Heylman, College of Engineering, Biomedical Engineering Department

Additional Advisors

Michael Whitt, College of Engineering, Biomedical Engineering Department

Abstract/Summary

The Prosthetic Thumb Project is a senior design project completed by Biomedical Engineering Undergraduate students at California Polytechnic State University. This senior design project is aimed at designing a prosthetic thumb for a Cal Poly Pomona student who lost their thumb in an accident last year. The patient has ultimately lost between 30-40% of functionality of his left hand, and so we would like to give him that mobility back. Originally, the patient was worried about having a prosthesis, and wanted something more stagnant that would resemble the look of the thumb he lost. However, after working with him, we determined that in order to regain functionality of the left hand, he would need a body-powered prosthesis that will move with his thumb residual in order to mimic the natural motion of a hand. Since we are designing a product for our customer, we still wanted to make a design that does not entirely look mechanical. The prototype of our design was generated using the 3D printers at innovation sandbox. Our parts were printed using PLA in order to utilize the free resources to students and keep the cost of the prosthetic low. When undergoing compression testing, the parts were tested using the instron in the Biomedical Engineering lab. The proximal and distal pieces were secured, and tested up to a force of 500 N. The proximal pieces experienced minor cracks, but still withstood the overall force without any internal support. The distal pieces withstood the force of 500 N with no cracks when the force can from the side. We also tested using a “hyper-extension” method, meaning we secured the prosthetic to a model of the hand, and hung weights off of the distal piece. The Prosthetic Thumb Group will be working on the final product that is being delivered to the patient next quarter as well. We plan on changing the material of the 3D printed parts to give the prosthetic thumb more strength.

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