3D printing can be a wasteful method of fabrication. The process is additive, so there’s no need to worry about removed material. Support material, purged spools of filament, priming towers and discarded prototypes add up. This waste is not significant on a worldwide scale because the 3D printing industry remains small. However, it is increasing. The waste generated is almost exclusively thermoplastic, and PLA does not biodegrade within a reasonable time frame. To make 3D-printing more sustainable, a CU Boulder group led by assistant prof Michael Rivera developed New coffee-based 3D material.
Rivera came up with this idea while working in a café and seeing how much used coffee grounds were generated. Rivera thought the grounds might still be useful even though they are usually used to compost. They can be used to provide structure because they are fibrous. Rivera only needed a method to keep them together so they could be 3D printed.
Rivera experimented with different additives before settling on a combination of coffee grounds and cellulose gum. He also added xantha-gum. Together, they formed a paste that was similar to peanut butter. After extrusion it can keep its shape, and then the part is dried to harden. Rivera says that after drying, the parts are quite strong. And even better, they are still highly biodegradable. The parts can be composted, just like coffee grounds. They will degrade in a short time. Or, parts can be pulverized and extruded to create new parts.
This coffee paste can be printed on 3D printers for consumers that are affordable with only minimal modifications. This 3D printer is similar to the chocolate 3D printer in that it only needs a syringe extruder. The total cost for a printer to handle this material would be only a few hundreds dollars, and it could work with conventional slicers and firmware.
There are a few disadvantages. It is a bad choice for fine detail parts because the extrusions are very thick. The material, which is biodegradable and can’t withstand exposure to elements, cannot be used for certain applications. However, for some applications, it could be an excellent choice to reduce our dependence upon thermoplastics.
