Used Plastic Bags Turned Into Useful Objects with a Standard 3D Printer

We all know that plastic waste is a problem. Even if you’re not the environmentalist type, you can’t deny the facts. According to the EPA, there were more than 14.5 million tons of plastic municipal solid waste in 2018 from containers and packaging alone. Not only does that plastic fill our landfills and oceans, it also represents a significant percentage of our oil usage. That is oil that is very quickly dwindling. Unfortunately, a great deal of that plastic waste is difficult to recycle, despite our best efforts. That’s why researchers from MIT Media Lab’s Tangible Media group have developed an innovative technique to turn plastic bags into useful objects with a standard 3D printer.

There have been many efforts over the years to convert plastic waste into usable filament for 3D printing, but that has proven to be a serious challenge. That’s partly because many types of plastic waste are less than ideal for 3D printing and partly because it is difficult to process that waste in a practical way. This method from MIT, dubbed “Therms-Up!,” makes that processing unnecessary. Instead of converting plastic waste into raw material, this technique uses the plastic waste — namely plastic bags — directly as a construction material. It works with just about any thermoplastic, including LDPE, HDPE, and PET. Those are the most common types of plastics used for packaging and containers, so there is a virtually unlimited supply of material for this technique.

Instead of melting down plastic bags and extruding the plastic, this technique utilizes a FFF (Fused Filament Fabrication) 3D printer’s hot end to create seals in those bags. This quickly and easily creates a series of air pockets and channels in the plastic bag, which can then be inflated to create a 3D object. By pumping air in and out, those can even be actuated. It works like this: you rinse out your empty Dorito’s bag and then lay it down flat on your 3D printer’s bed. A special g-code file is then sent to the 3D printer, which causes the printer to drag its hot end across the plastic bag in the desired pattern. Because the bag is made of thermoplastic, the hot end melts and seals seams in the bag wherever it makes contact. The entire process takes just a few minutes. Then the bag and can be removed and inflated. Depending on the seam pattern, the bag can become anything from a pillow to a soft robot.