Let’s say you’re a supply manager in the U.S. Marines at a forward operating base, faced with a problem. Radios are coming back from the field with a certain plastic bracket that frequently breaks. The piece is a long-lead item and getting replacements takes weeks. Every day a couple of radios come back broken. In the meantime, there is a stock of recyclable polyethylene terephthalate (PET) from used water bottles, milk jugs and yogurt containers at the base.
The U.S. Army Research Laboratory, in conjunction with the U.S. Marines, has developed a way to turn recycled PET like used water bottles, milk jugs and so forth into feedstock filaments for 3-D printing. To achieve this, they used Thermo Scientific Process 11 twin-screw extruder in the process. The Process 11 extruder is the ideal fit for the mobile recycling facility that the U.S. Army envisions. Using PET feedstock made with the extruder, the mobile facility can easily manufacture supplies in hours, not only saving time and solving long-lead problems, but reducing costs as well.
Purchased in 2016, the Process 11 extruder has helped the Army Research Lab experiment with the fabrication of several materials used in military facilities and on the battlefield. Once they hit on the method of using the extruder for recycled PET, they knew they had a winner.
The U.S. Army Lab tested recycled PET materials against commercially available ABS materials and found they had similar strengths–which was something of a surprise, since PET is not widely used as a feedstock for additive manufacturing due to high melting temperature, water absorption and issues with crystallinity. However, recycled PET did not exhibit the same problems. It’s the high-tech version of spinning gold from straw!
“Ultimately, we’d like to produce the best possible feedstock we can from recycled plastics and waste materials,” ARL researcher Dr. Nicole Zander said. “Future work will involve testing 3D-printed long-lead parts against original parts to determine if they can be a suitable long-term or at least a temporary replacement.”
Not only can the military service find uses for filaments made from recycled plastics, but municipalities, schools, and universities around the world could also create value-added materials for the growing additive manufacturing market segment from recycled PET. All they need to get started is a little knowledge—thanks to the U.S. Army Research Laboratory, a 3-D printer, and the wonderful Thermo Scientific Process 11 twin-screw extruder.
Recently, Plastics Technology picked up on this story, read it here.