Onwards and Upwards: ABS is King

A project log for Mechanized Prosthetic Foot

The purpose of this project is to design and build a fully mechanized prosthetic foot that is more accessible than current solutions.

AractapodAractapod 09/19/2016 at 02:220 Comments

The group decided to record a video of our 75% infill compression sample being compressed. This gave the group a more in depth insight into the buckling nature of the part failure. After printing the individual components of the full scale model, the group assembled it using press fits and then prepared the model for testing. To test the full size model under compression loads the group repeated the process it had used for the compression testing. Using a baseline force of 178 pounds with a safety factor of 3 to consider the test a success, a force of 534 foot pound needed to be applied to the sample. The group placed the model in the machine and slowly loaded the machine until the indicator displayed 535 ft pounds of force shown in. Here is a video of the foot being compressed. Having tested the model without failure to the desired load the group proved that ABS plastic is a viable material for the structural design of the prosthetic foot. ABS is a very simple material to print with using FDM due to its melting temperature. ABS is also ductile as can be seen from the stress-strain curves provided in the previous update. Ductility is important because it allows the parts to flex and stretch a little bit reducing the threat of parts breaking unexpectedly.