The Idea2Product lab is a makerspace at Colorado State University that provides engineering supplies and equipment for CSU and K-12 students. While it provides a variety of services, its main focus is Fused Deposition Modeling 3D printing.

This method entails mechanically feeding spools of plastic filament into a nozzle, where it is heated into a semi-liquid state. The printer then positions the nozzle according to computer instructions and layers material up into a three-dimensional shape.

“We provide users PLA and PETG: Both of those are different kinds of plastic,” Lab Manager Charissa Feldmann said. “PLA is going to have less structural integrity than PETG. … It has a lower melting temperature, which makes it easier to print with.”

While Idea2Product gives priority to engineering students doing class projects, the lab is open to all students and majors.

“Any week that stuff’s due, every single one of our printers is booked out,” Feldmann said. “As more of the semester and year goes on, more people get trained and more people discover we exist, so then we just get busier with the nature of that, too. … Definitely the highest use is going to those FDM printers.”

This accessibility empowers students’ creativity in unique ways, but the amount of usage also presents problems, as 3D printing produces plastic waste. Because FDM printing works by layering on top of earlier material, it can’t automatically print shapes with overhangs. To do so, it must print “supports” to layer on top of, which get disposed of. Printer malfunctions and design flaws also contribute to waste.

“A lot of prints fail; it’s just kind of the nature of 3D printing,” Lab Operations Manager Collin Colwell said. “We also see, like, a lot of waste from projects that just don’t work the way they’re intended to.”

Waste from 3D printing is difficult to track, but, according to a 2021 study, it was estimated plastic consumption for 3D printing reached 18,500 tons in 2020, likely producing 5,000 tons of waste.

“The amount of plastic, roughly, that we generate in a week in waste is about 10 kilograms,” Colwell said. “So call that 22-ish pounds.” 

This totals to roughly 350 pounds per 16-week semester. While PLA and PETG are recyclable, local recycling centers, including the City of Fort Collins’ Timberline Recycling Center, cannot process these materials. However, by utilizing specialized technology, the lab can recycle the material in-house. 

The process starts by separating PLA waste from PETG waste. 

“You can’t process them together, and that’s important to know for later when we talk about recycling them,” Colwell said. “They have different melting points and different chemical makeups, different properties — they’re different plastics entirely.” 

Once sorted, waste gets broken down into small chips using a mechanical grinder, which then is moved to a dehydrator, removing moisture that could disrupt the recycling process. Afterward, the chips can be melted down and shaped using a special injection molder.

“It’s a hand-operated injection molder, not industrial,” Colwell said. “It just has, like, a big heater and a plunger that pushes the plastic down.”

This melted plastic then enters a mold and cools. Using injection molding, the lab can create a variety of objects, from flower pots to chess sets.

Using a different machine, staff members even have the capability to recycle chips back into usable FDM filament, though the feasibility of the process is still a ways off.

“It’s very finicky to get to work,” Colwell said. “Not only do you have to assume that you have pure PLA and PETG, you also have to melt it at the correct temperature and cool it at the correct speed, or else you’ll end up with a filament that is too inconsistent in its diameter along its length to actually be used in the extruder. If you look at a normal spool of filament, we’re talking about a deviation diameter of, like, microns, so the fraction of a millimeter.”

This process is neither cost nor time effective. Colwell said making a full roll of filament takes upward of three hours, assuming perfect conditions and execution. As a result, it costs much more to pay staff to make recycled filament than to buy new filament in bulk.

“What we have as I2P, we can’t do that right now reliably,” Feldmann said.

Even if the lab had the resources to make large amounts of new filament, there are limits to how much PLA and PETG can be recycled. When the materials are repeatedly melted, the molecules that give the plastic its structural integrity degrade, meaning the quality of the material goes down the more it’s recycled.

“Every time you melt PLA, it breaks down further in its chemical makeup, same with PETG,” Colwell said. “It’d be essentially a one-time use, and then you wouldn’t be able to cycle it again.”

Injection molding helps cut down on waste, but the present rate of generated waste greatly exceeds the lab’s recycling rate. The current injection molder can only use smaller molds, leading to relatively little material getting recycled.

“We have yet to really throw anything away, but we do have a very large backlog of material that needs to be used.” Colwell said. 

Despite these challenges, the Idea2Product lab continues to look for additional ways to recycle plastic and improve systems.

“We are always looking for stuff for the lab that makes us more sustainable,” Colwell said. “It is naturally very hard to be sustainable in a lab that uses as much plastic as we do, but we do try our best.”

Reach Maxine Bilodeau at science@collegian.com or on social media @RMCollegian.