This week, we got very exciting results: a thin stream of melted plastic!
After rinsing out the oil typically found in the pipe we chose to use, we began heating our vessel (the pipe and its lid), which had already been fitted with a small hole for the filament. Because our chamber is quite small (for easier testing), we repurposed the heating element of the hot plate to wrap around the vessel to allow for greater contact (as shown in the attached image). The heating element was quite malleable and we were able to coil it by wrapping it around a rod.
Our repurposed heating element and heating chamber
Then, we began to heat the plastic. Because we did not yet have the vacuum, which we plan to later use to avoid air bubbles, we simply situated the plastic in the repurposed hot plate element. The heating process was slow as the coils in the hot plate left considerable space between the heating element and the heating chamber. We hope to tighten the coils around the chamber for next week, to make a more efficient system. Once the chamber was sufficiently hot (around 200 degrees celsius), we connected it to the air compressor and let it run. Unlike our previous, non-pressurized experiments, in which the the plastic was as thick as glue, here the plastic flowed out of the chamber as a liquid! We are looking forward to next week, when we’ll hopefully have the benefits of the vacuum and more efficient heating, and we can begin extruding plastic!