I tested different waste materials and “bioplastic” options and documented the physical differences and characteristics of changing ratios of bioplastic and waste material. My team and I settled on spent coffee grounds and eggshells, as they were both abundant and easily accessible as waste material.

I was also tasked with devising the method of deposition for the waste material, bioplastic (gelling agent), and the binder, and then making some of the pieces.

My initial idea was to have a powder bed, and to use an Intel Realsense L515 Lidar camera I had borrowed to level the bed; after leveling, we would project the shape onto the bed and either manually deposit the binder on it, or have it done automatically.

I got some depth data from the lidar camera, but I quickly realized this was not the best tool for the job, and we ended up going with a more analog approach because of time constraints.

We settled on a more “manual” approach to the binder jetting, with the steps outlined on this diagram:

We mixed the material and gelling agent (for example, eggshells and HEC), and spread a layer on the tool bed. We then place the template on top and spray water; after allowing a little time to settle, we lower the bed and place a new layer, and repeat until done.

The parts made have very little structural integrity and are not really functional, but the whole process was very helpful as a proof of concept; there is more work that needs to be done before turning these into functional parts, however, it was a good start and a great learning experience.

Here are some more images of our work:

Worked alongside Jeonghyun Yoon, Linh Pham, and Song Dong on this final project for the course SCI 6486 Biofabrication. A design engineering course at the Harvard Graduate School of Design.