November 4, 2021
Nearly all shea butter comes from the "shea-belt," which spans many sub-Saharan African nations. Women-run co-ops in countries such as Ghana are responsible for processing shea nuts into shea butter. One essential step in processing shea butter requires roasting the shea nuts over a fire in a hand-cranked rotating drum. The women in these co-ops often roast shea nuts for hours on end, all while enduring smoke inhalation and shoulder, joint, and back pains. Furthermore, due to inefficient wood burning, the co-ops are forced to use more fuel than is necessary and emit harmful pollutants into local communities. Accordingly, one of the major projects at Burn Design Lab is the development of an improved shea roaster.
While BDL's shea roaster prototypes have improved both the roasting capacity and efficiency, we knew from direct user feedback that the women roasting shea nuts wanted a less physically taxing method to rotate the drum. Upon my arrival at BDL, I joined the Improved Shea Roaster project and was put in charge of developing a more ergonomic way to turn the shea roaster drum.
Within the first two weeks at BDL, I had designed and built a treadle prototype to rotate the drum. A treadle is essentially a pedal that translates the alternating motion of a foot pedal to rotational motion, a similar principle to a piston. To put it bluntly, my first prototype was not very successful. It was a bit too small and tended to get stuck at top-dead-center and bottom-dead-center. However, I can confidently say that I learned more from this prototype than any of the others. For example, I learned the importance of designing with fabrication in mind. I also learned new fabrication principles, such as how to properly weld and select suitable materials.
With the second prototype, I took a different approach. I designed an adjustable treadle to determine what characteristics improve or hinder the treadle's performance. The goal for the second prototype was not to design a final product, as it required precision machines to build, but to figure out the ideal specifications for the "final" prototype. The second prototype was successful in its purpose. It allowed me to experiment with different measurements without having to rebuild or redesign a new treadle. After I found the ideal geometry for the treadle, I could begin designing a more replicable model.
By the time I began working on the third prototype of the treadle, I was in my third and final month at BDL, so I knew this would likely be my last iteration. Using the specifications gained from the second prototype, I shifted my focus towards making the treadle cheaper and more easily constructible. Since the end goal is for this ergonomic drive to be remanufactured in Ghana, ease of construction is essential. To make the treadle cheap, I designed it to be made almost exclusively out of square-tube, with very few specialized parts. To make the treadle easily constructible, it is primarily a bolted assembly rather than welded. Eliminating most of the welding reduced any chances for welding deformations, which would hinder the performance of the treadle. The three treadle iterations resulted in an ergonomic and cheap alternative to spin the shea roaster drum. The third prototype was quite easy to use and was very forgiving to construct.
There are intangible things, too, that resulted from my time with BDL. Namely, I found a sense of community and learned to be self-reliant.
I remember how nervous and excited I was on the ferry, from Tacoma to Vashon, on my first day at BDL. This was my first internship experience, and I did not know what to expect. But when I first walked in the doors at BDL, a laid-back office space filled with friendly people and warm personalities met me. At lunchtime, we ate outside, and afterward, we tossed a frisbee around in between laughs. By the end of my first day or two, I knew I had found a gem of an internship.
Even so, at the start of my internship, I felt afraid to make any significant decisions. I felt more comfortable following the structure of school, where you receive a question, figure out the answer, and then return it to your supervisor. However, I soon realized that I was not only allowed to make decisions but was also encouraged to do so. Once I became confident taking responsibilities into my own hands and became comfortable with the consequences (for better and worse), I realized my true potential. If I had a vision in mind, I could achieve it. So ultimately, while BDL has given me a wealth of technical knowledge, friendships, and memorable experiences, I will forever be most thankful for the shift in my mindset.