Making 3D printed products from recycled plastic milk cartons
06 March 2013
Michigan Technological University’s Joshua Pearce is using open-source 3D printing software and shredded milk cartons to make everything from his lab equipment to his safety razor.
Using free software downloaded from sites like Thingiverse, which now holds over 54,000 open-source designs, simple, open-source 3D printers are able to make all manner of objects. However, one impediment to more widespread use has been the cost of filament - the raw material that 3D printers transform into useful objects.
Plastic milk cartons, on the other hand, are costly, either to recycle or to bury in a landfill. But if you could turn them into plastic filament, Pearce reasoned, you could solve the disposal problem and drive down the cost of 3D printing.
So Pearce and his research group decided to make their own recycling unit, or RecycleBot. They cut the labels off milk cartons, washed the plastic, and shredded it. Then they ran it through a homemade device that melts and extrudes it - their process is open-source and free for everyone to make and use at Thingiverse.com.
The process isn’t perfect. Milk cartons are made of high-density polyethylene (HDPE), which is not ideal for 3D printing. “HDPE is a little more challenging to print with,” Pearce says. But the disadvantages are not overwhelming. His group made its own climate-controlled chamber using a refrigerator and an off-the-shelf humidifier, and achieved good results.
The group determined that making their own filament in an insulated RecycleBot used about one tenth the energy needed to acquire commercial 3D filament. They also calculated that they used less energy than it would take to recycle milk cartons conventionally.