The advancement of 3D printing technology has ushered in a new era of innovation and creativity. However, with this progress comes the challenge of managing the resulting waste streams effectively. Traditional infrastructure makes recycling difficult, an environmental issue the leaders of the Brown Design Workshop (BDW) are attempting to solve.
The RE-PLASTIC program, with its acronym penned by Dr. Leo Kobayashi, Professor of Emergency Medicine at the Warren Alpert Medical School at Brown University and doctor at Rhode Island Hospital, stood at the onset of this challenge, proposing an ingenious solution to not only tackle the issue of 3D print waste but also harness it for sustainable purposes. Most recently, a Hazeltine Innovation grant has allowed BDW Director and Professor of the Practice Louise Manfredi to tackle the logistics of the idea formulated by Kobayashi and former BDW director Chris Bull.
This pioneering initiative explores the collection and processing of 3D print waste, transforming it into repurposed 3D print filament material. The primary objective is clear: to establish a comprehensive waste re-purposing pipeline, encompassing collection, sorting, cleaning, shredding, granulating, and extruding 3D print filament. Beyond waste management, RE-PLASTIC has ambitious academic and community-oriented goals. By integrating student monitors into the process, the program seeks to provide interactive learning experiences within a “living” campus laboratory space. This approach not only enhances academic exposure but also fosters a deeper understanding of sustainability through hands-on engagement.
The beginnings of the project were simple enough: Kobayashi, who also works in medical device development, was in the BDW printing and producing 3D filament parts when he took notice of the amounts of collateral waste with each print. Through conversation with Bull, and a spring 2023 Sustainability Seed Grant from the University, the beginnings of a recycling program were started.
But it was thanks to the 2024 Hazeltine Faculty Innovation grant awarded to Manfredi where the multifaceted approach that included 3D printing and material recycling was able to take its current form.
“What we’re trying to do in the BDW over this year,” Manfredi explains, “is to map as many of the material flows and processes as possible. Two elements that we felt were measurable was rethinking the wood workshop, which is one part of the grant. But a larger part of it is thinking about the proliferation of 3D printed models and artifacts that leave the BDW and the waste that it does in fact, generate.
“Doing some cursory analysis of the environmental impact of PLA (polylactic acid), which is our preferred filament to use here, costs us 3.5 kilograms of CO2 equivalent per kilogram of material, which is actually higher than oil derived plastics. The way that PLA is marketed is that it’s okay to throw away because it’s biodegradable, but PLA is only biodegradable under certain conditions, and landfill is not one of those conditions.”
Manfredi and interested parties decided to create a closed loop recycling program where the waste would become feedstock within the BDW. “At the moment, it’s very heavy on human capital,” she admits.
A group of research assistants, made up of both graduate and undergraduate students – some engineering concentrators and some not – are collecting data and producing life cycle assessment reports. They are working with Carbon Graph, a digital platform that enables companies to calculate and share the carbon footprint of their products or services. “Students are getting an opportunity to work with a company that leverages AI and collaborative web platforms to speed up the process of creating life cycle assessments from multiple months to a few days, which is a big time sink, when you’re trying to characterize flows through a process,” Manfredi said.
“As part of that, we’re offering open source reports for anybody who wants to understand the process, and then take it and run with it and optimize it,” she said. “We’re trying to get as much information out into the world, not behind a paywall, as possible.” A recent grant bid was unsuccessful, but Manfredi continues looking for funding opportunities to double the capacity of extruded filament to make recycling a truly viable option.
Included in the source reports are experimentations of things like how much virgin PLA needs to be mixed in for successful extrusion, or determining how many times the material can be downcycled until it is no longer viable as 3D print material, at which point it is transferred off to create sheets of material that can be laser cut.
“There is so much uncertainty in this particular recycling process that we’re trying to strategize ways to understand or point to why a certain batch of PLA re-filament is not adequate,” Manfredi said. “We’re looking at humidity sensors within our collection boxes to see if there were spikes in the data that may explain why the plastics aren’t performing correctly, or perhaps the amount of time it’s been in the box that may have had some impact on the quality of the material that we get post recycling, or if there were contaminants in the plastics. How do we stop the amount of air bubbles coming through in the extrusion hoppers? There are a lot of variables.
“That allows us to keep experimenting, and it becomes less guesswork and more refined experimentation and hypothesis driven work. And what’s nice about it is there are so many opportunities for students to learn about the impacts of materials, such as how one processes and reprocesses,” she said.
This leaves the question of what if, after all the data collection and experimentation and sharing – it turns out the process is not economically viable, efficient or ecologically sustainable? What then?
“Then we will need to evaluate based on all of the data points and ask ourselves, what is the most responsible way to proceed? The answer might be to invest in sending our waste to industrial composting or rethink the materials that we’re using – there’s opportunity for new bio-based materials all the time. And a good example might be PHA, which is made from renewable resources like plant oils, sugars, starches, methane, and wastewater. It’s another material that could potentially replace PLA in the future. There’s always interesting innovations for us to introduce students to,” Manfredi said.
*Amanda McGregor, Deputy Director for News and Editorial Development at Brown University, contributed to this story