Students and faculty at the 3D Print and Laser Cutter Lab at Arizona State University have devised an efficient new way to recycle plastic waste to be used in future design projects, furthering the university’s Zero Waste initiative and saving the lab money on supplies.
“We got to work with our [associate] director in Zero Waste, and she brought forward an idea of creating a single-loop system in the lab,” said Myrna Martinez, the academic facilities specialist for the Ira A. Fulton Schools of Engineering, referring to ASU’s Zero Waste Associate Director Alana Levine. “So this is kind of a program she’s been working with — with many different labs — about reducing their waste, repurposing their waste in some form.”
Martinez runs the 3D print lab, leading educational programs, managing lab operations and supplies and helping students learn about 3D printing and laser cutting. Martinez and Matthew McWhorter, another academic facilities specialist at the engineering school, wanted to find new technologies to introduce to the lab and discovered the Filabot extruder system.
“We wanted to expand a little bit towards kind of like the manufacturing process in engineering,” Martinez said. “And to kind of bring it to a full circle of manufacturing, we thought, ‘Hey, why not recycle the waste PLA in the lab, since we’re producing a lot?’”
PLA, also known as polylactic acid or polylactide, is a biodegradable polyester made from renewable resources such as corn starch. It is one of the most common bioplastics in the world.
“With the discarded plastic, it’s going to be in odd shapes, large chunks, so we actually have to chop it down to a small, little eighth-of-an-inch or smaller bit,” Martinez said. “We’ll have some — what we call — raft, which is the material that is sacrificed for the project to be built on top of. So, that material gets ripped off the finished project, and it basically would just make its way to the trash.”
Students in the 3D print lab put the raft and other discarded plastic through a wood chipper to create a “mulch” of tiny pieces that are then fed into a melting chamber before being extruded, or squeezed out, into strands about a millimeter in diameter.
The lab at ASU uses a Filabot EX2 Filament Extruder, a three-stage system specifically designed to melt tiny beads of 3D printing polymers into long, even strands of flexible filament that are cooled and rolled onto spools. The spools are added to the lab’s inventory to be fed into the 3D printers.
“I think it’s a pretty unique system where we’re taking pretty much 100 percent of our waste and repurposing it,” Martinez said.
The PLA recycling venture was both a cost-saving effort and an initiative in sustainability, said senior mechanical engineering student Ruy Garciaacosta. Members of the lab are encouraging others to bring in their discarded PLA to recycle using the ASU system, he said.
“There is a huge cost benefit to just taking the parts that aren’t usable and then recycling them to potentially be usable for more prints down the line,” Garciaacosta said. “You can probably take a whole box full of materials and print an entire capstone [project] with that entire box, and potentially more, just with recycling a box full of disregarded PLA parts.”
Garciaacosta said students in the 3D print lab call their system “Bob Ross, because it takes all of our little mistakes and then turns them back into something useful.”
Kenny Truong, a sophomore mechanical engineering student, further explained the single-loop system Martinez described. Vertical integration allows the lab to purchase new material less often and make use of material that would otherwise be sent to a landfill, he said.
“Here at ASU, we’re really big into sustainability, and especially with 3D printing there’s so much waste material,” Truong said. “We usually use PLA. Although it’s biodegradable, it still takes thousands of years. The industry doesn’t really recycle it because it’s hydroscopic, so it absorbs a lot of water and it’s kind of horrible to recycle.”
Martinez said trying new things in the lab is all about finding successes while critically identifying failures. It is uncertain how many times PLA can be recycled before its durability begins to deteriorate, she said.
“We realized that it’s going to happen,” Martinez said. “You can only recycle it so much before the plastic just starts to really be more brittle.”
Martinez said she would like to stock spools that have been reused a couple of times to donate to K-12 science, technology, engineering and math (STEM) programs with 3D print labs to make design and exploration more available to young minds.
Experience with 3D printing and design is becoming increasingly advantageous to students entering STEM industries such as manufacturing, aerospace, chemical engineering and even medicine, Martinez said. Even entrepreneurial ventures in art and architecture could benefit from the ability to conceptualize and print a physical product model.
“A lot of students lack that sort of knowledge, and that sort of hands-on experience is not something taught in a classroom,” Garciaacosta said. “Right now I actually have a career lined up at Honeywell, so I’ll be working there doing design work, and hopefully I can take what I’ve learned in the 3D printing and laser cutting lab and apply that to doing design and being able to make the items that the company needs.”
Prototyping mechanized parts is often the most difficult and time-consuming part of engineering, Truong said. Creating a tangible model that can be scrutinized and tested is a vital part of product development, and 3D printing makes that possible, he said.
“I’ve always been interested in aerospace and aeronautical stuff, so 3D printing is a big thing,” Truong said. “The U.S. Marine Corps is using it for the F-35 project, and for prototyping different parts for the aircraft.”