One of today’s biggest environmental problems is the high amount of plastic waste. Although Western countries are gradually taking action with successful recycle programs, Third World countries still have a very high amount of polluting litter lying on the streets. On the other hand there’s 3D printing, where plastic is needed for filament to make certain products. Filament prices for 3D printing are extremely high, with average costs of about 30 dollars for a spool of plastics. Why wouldn’t we combine these elements and turn it into something better, is what a team from the Michigan Technology University (MTU) must have thought.
And so a research group led by Joshua Pearce, a professor of materials science, did a study on plastic waste. And as it turns out, using plastic waste for plastic 3D printer filament is a lot cheaper than recycling it. This is due to the fact that using it for filament costs a lot less energy. If you take into account that one of the biggest disadvantages of 3D printing today is that it’s polluting because it uses so much plastic, than the results from this study are even more amazing.
What the team did was a so-called life-cycle analysis on an ordinary milk jug made from HDPE plastic. For 3D printing it worked as follows: the jug was cleaned, cut into pieces, it was run through an office shredder and a RecycleBot, and then turned into filament. In comparison with an average recycling program, this approach used about 3 percent less energy.
This difference becomes even bigger whilst comparing it to smaller towns. In this study they used Houghton as an example of such towns. In this city people have to transport the plastic to be collected, then again to be recycled, and a third time to be made into products, according to Pearce. Using plastics for 3D printer filament would save as much as 70 to 80 percent of energy. In addition, if you would recycle your own milk jugs, it would save you as much as 90 percent on energy costs in comparison to making virgin plastic from petroleum.
Another advantage of this approach is that making your own filament is cheaper than buying it. “Filament is retailing for between $36 and $50 a kilogram, and you can produce your own filament for 10 cents a kilogram if you use recycled plastic,” Peace says. “There’s a clear incentive, even if you factor in the cost of buying the RecycleBot.” The MTU adds that commercial variants such as the Filastruder cost under 300 dollars. Another example could be the Noztek Pro – we interviewed Noztek’s Steven Forster about this filament extruder, which you can read on 3dprinting.com.
The company used HDPE plastic, but as a user you have to know that this kind of plastics can’t be used in all cases. “It shrinks slightly as it cools, so you have to take that into account,” says Pearce. “But if you are making something like a statue or a pencil holder, it doesn’t matter.”
To return to the Third World pollution problem, it would be an idea to actually use this technique in such countries. The Ethical Filament Foundation therefore became interested in this new way of recycling plastic. The goal of the foundation is to improve the lives of waste pickers. “In the developing world, it’s hard to get filament,” says Pearce. “And if these recyclers could make it and sell it for, say, 15 dollars a kilogram, they’d make enough money to pull themselves out of poverty while doing the world a lot of good.”
The study was called Life-Cycle Analysis of Distributed Recycling of Post-consumer High Density Polyethylene for 3-D Printing Filament and it was a production of Pearce in conjunction with fellow MTU professors Megan Kreiger, Meredith Mulder and Alexandra Glover. The study was published in the Journal of Cleaner Production on February 12. Via this link you can read an open access version.
Image credits: MTU.