The 3-D printing revolution has changed the way we think about plastics. Everything from children's toys to office supplies to high-value laboratory equipment can be printed. The potential savings of producing goods at the household- and lab-scale is remarkable, especially when producers use old prints and recycle them.
Buying plastic filament for printing can be expensive, says Joshua Pearce, the lead researcher in the Open Sustainability Technology group at Michigan Technological University. Pearce and his students have whittled the cost of printing to ten cents per kilogram -- down from $30 per kilogram.
They made this leap by recycling plastic that had already been printed, using a recyclebot and plastic resin codes developed by the team.
In a new paper from the research group, published in Resources, Conservation and Recycling, the authors lay out how they achieved this price reduction and how to recycle 3-D printed objects more broadly.
"The centralized paradigm of both manufacturing and recycling is being challenged by the rise of 3D printing," Pearce says, explaining that labeling and reusing materials is voluntary.
Current labeling schemes, however, are not detailed enough for 3-D printed recycling. Plastic is not just plastic; there are many kinds, and specific polymers behave in specific ways -- which makes a big difference for 3-D printing.
"We want to know about polymers the same way a chemist would," Pearce says, admitting that the seven codes in the US recycling system fall short. In comparison, China has 140 codes for different polymers. "Currently, the most common 3-D printed plastics are grouped in the category seven polymers in the US," he adds.
That seven category is the catch-all group and means little as a label. Most widely used and conventionally produced plastics fall into the first and second categories -- the same groups that cover plastic water bottles and milk jugs. These can be recycled for 3-D printing, but the two most common plastics for 3-D printing are PLA (polylactic acid) and ABS (acrylonitrile butadiene styrene). PLA is often used as biodegradable dinnerware and ABS is the hard plastic of Lego blocks. Although they're distinctly different, being lumped with so many others in the seven categories makes it difficult to reuse these plastics in 3-D printing.
To overcome these issues, Pearce and his team developed a new resin code identification system based on the Chinese codes. They focused on polymers that could be recycled in 3-D printing and made the system expandable to accommodate innovations in printing and plastics.
"We also demonstrated how to incorporate recycling symbols into 3-D printed objects using open-source and parametric scripts for our new print codes," Pearce says. The scripts are freely available on Appropedia.
The labels themselves are novel in 3-D printing. Standard recycling labels are small, slightly raised and often placed on the bottom or another convenient location. But with 3-D printing, the labels can be woven into the design itself. A pencil holder can reveal its secret polymer type as light shines through its plastic bottom or a broken screwdriver handle can be cracked open to show its code number. Neither is possible with conventional manufacturing.
The inventive ways to use recycling labels along with the new code system and free scripts are a big step towards better 3-D printing recycling, which is good for the environment. Pearce hopes to make the practice widespread.
"To make this actually happen, the coders for the slicing software need to make this an option," he says. "So we're sharing the source codes so they can incorporate them into their software for free, so everyone can use it."
The paper was co-authored by Pearce and students Emily Hunt, Chenlong Zhang, and Nick Anzalone.
Joshua Pearce | EurekAlert!
Five developments for improved data exploitation
19.04.2017 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI
Smart Manual Workstations Deliver More Flexible Production
04.04.2017 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...
Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.
A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
21.04.2017 | Physics and Astronomy
21.04.2017 | Health and Medicine
21.04.2017 | Physics and Astronomy