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e s f home link - e s f college of environmental science and forestry

Waste not, want not

Grant Received for 3D printer filament recycling, production pilot plant

Dan Fougnier and Dr. Kelley Donaghy in the lab

Dr. Kelley Donaghy and Dan Fougnier, graduate student, received a grant of $9,300 from the Society of Plastic Engineers to launch a 3D printer filament recycling and production pilot plant.

The funds are provided to purchase a commercial shredder and extruder. The shredder will chop the waste plastics into small pieces and the extruder will melt it, then form it into filament to be used again in a 3D printer, to provide "cradle-to-cradle" filament recycling, according to Donaghy.

Additive manufacturing - 3D printing - is the process of building a three-dimensional object through a computer-controlled process layer by layer. In 3D printing the "ink" is a thermoplastic filament that is fed through a heated extruder nozzle and deposited only where you want it.

Donaghy uses a 3D printer in her inorganic chemistry course where her students print with high-copper content filaments which are then heated at high temperatures in a reducing atmosphere to burn off the plastic and leave behind pure metal, simulating the isolation of metals from their ores.

"As we developed our lab and shepherded our first students through the design, slicing and printing phases of the project, we generated a lot of failed prints and lots of prototypes before printing with the copper filament. In short, we were generating a lot of plastic waste. We started to ask around about what could be done with this waste and the answer was: not much," Donaghy said. "This didn't seem to fit with what ESF stands for, so we decided to look into doing something about it."

The recycling and production plant will allow for the study of a localized effort to recycle, reduce and reuse 3D printer filament, particularly polylactic acid (PLA) the current leading printer filament. While PLA is a biodegradable plastic, most waste is packaged into plastic garbage bags that are not themselves biodegradable. Furthermore, landfills seldom offer the requisite conditions for efficient PLA biodegradation, Donaghy said. "Therefore, a recycling plant which produces a recycled 3D printer filament is a niche market currently."

"A lifecycle assessment as well as an environmental impact assessment can be done on this plant to determine the benefits of localized small-scale community recycling plants. This project will create a set of standard operating procedures for a small-scale plastics recycling plant for local schools and municipalities for plastics that are not recycled by local waste handlers," said Donaghy.

The pilot plant will start with PLA, but Donaghy and Fougnier plan to branch out to other materials that aren't locally recycled such as polystyrene (PS) and polyethylene terephthalate (PET).

"China is no longer accepting dirty-stream plastics for recycling which makes finding ways to recycle discarded plastics at the local level more important," Fougnier said. "3D printing filament presents an opportunity for redirecting a portion of this waste stream."

There is still a lot to do and a lot of fundraising needed to get the project completely off the ground, but the extruder and shredder are being ordered. Donaghy and Fougnier are committed to getting the recycling facility operational so the general chemistry service track can learn to make filament from scrap plastic by January of 2019.