Trash Technology: 3D Printing With Recycled Material

Lee Rannals for — Your Universe Online

The future of 3D printing is still being determined by researchers in laboratories, and one new project is helping to shape that future, with trash.

Michigan Technological University´s (MTU) Joshua Pearce and colleagues are working on a tool for 3D printing called a RecycleBot that turns trash like empty milk cartons into 3D printing material. The tools are open-source, and the mechanical and electrical designs are currently available for free online (here and here), so any 3D printing enthusiasts out there who have a mechanical background can go ahead and start turning their trash into 3D printing treasure right away.

RecycleBot melts down milk jugs, after they have been shredded, and turns them into a spaghetti-like strings of plastic. Not only does the recycling unit help to save a little cash from your trash, but it is also energy conscious, as well. The recycling unit only uses about a tenth of the energy needed to acquire commercial 3D filament, and also uses less energy than it would take to recycle the milk jugs.

According to Pearce, 20 to 30 milk jugs are able to make about $30 to $50 in plastic you might buy online for your 3D printer. However, the plastic being created isn’t quite as strong as some available for 3D printers like those by MakerBot. Milk jugs are made of high-density polyethylene, or HDPE, which is not considered to be ideal for 3D printing.

“We currently are in the middle of a massive study of 3-D printed material strengths,” Pearce told redOrbit. “It is a tricky problem because we want to give real values for what users can get from their current printers, but the properties of the part are highly dependent on the slicer settings used and being dialed into the sweet spot of a printer+material combination. There are also important environmental variables (e.g. temperature and humidity during printing and used for filament storage). All of the current literature is only about the high-end commercial printers, we want to give everyone the ability to do the same type of mechanical engineering for RepRap printed components.”

3D printing is something that has gained popularity in the last few years and Pearce believes the craze for these devices will only continue.

“Open-source 3-D printers have created enormous price competition for rapid prototyping businesses,” he told redOrbit. “Now for a few hundred dollars you can have a 3-D printer in your living room that spits out products of higher quality than what $20,000 purchased in commercial rapid prototypers even a few years ago. Costs are still dropping as printing quality improves. I am fairly confident that we are well on our way to having a 3-D printer in every home creating a real distributed and localized digital manufacturing infrastructure.”

However, when it comes to the RecycleBot, itself, Pearce says the future is a little less clear than that of 3D printers.

“Initially, I think we will see different flavors of RecycleBots in locations with heavy 3-D printer usage (e.g. makerspaces, schools, and Fab Labs) then expand to cottage industries (e.g. your neighborhood filament supplier) or community centers (e.g. libraries),” he said. “Eventually, if 3-D printing becomes popular enough and RecycleBots are redesigned to be made with mostly 3-D printed parts, people will just make them at home to reduce the hassle of going to the local filament supplier or waiting for Amazon deliveries. No matter what, as RecycleBots become more popular, the competition will force the price of commercial filament down for everyone.”

Pearce’s and his colleagues’ research on the RecycleBot will be appearing in both the Proceedings of the Materials Research Society and the March issue of Rapid Prototyping.