Photo: Derek E-Jay/Flickr
3D printing items at home has been touted as potentially being better for the environment than manufacturing them in a factory. A new life-cycle analysis backs the claim: printing certain plastic goods at home uses significantly less energy and resources than does manufacturing the same goods overseas and shipping them to the United States.
Researchers looked at the production of a plastic orange juicer, a children's toy building block, and a waterspout, and making them in either ABS or PLA plastic. The study, published in Sustainable Chemistry & Engineering, found that home printing using existing technology can reduce total energy use by 41 percent to 64 percent compared to traditional factory production and shipping. If the energy source was solar PV, energy use was 55 percent to 74 percent lower than conventional plastic manufacturing.
That's for using PLA, a plastic made from renewable sources like cornstarch, and using a 25 percent or lower fill. Using a 100 percent fill with PLA actually used more energy than conventional manufacturing. Using ABS plastic, which requires higher temperatures for production, resulted in "less pronounced" environmental benefits.
Some of the energy savings results from using less raw material in 3D printing, says report author Joshua Pearce, of Michigan Technological University. "Children's blocks are normally made of solid wood or plastic," Pearce said, whereas with 3D printing blocks can "be made partially or completely hollow, requiring much less plastic."
Energy required for production of a variety of materials, via Sustainable Chemistry & Engineering
There's also a critical point in that statement and in the image above. If you take a look into the greenhouse gas emissions for production of the children's toy block you'll notice the column all the way to the left is the one for a block made out of wood. Even using the standard US electrical mix (which is pretty dirty, a bit under half coming from coal), a wood block is a miniscule fraction of the greenhouse gas emissions of any of plastic scenarios the report tested.
None of which diminishes the research, or the potential for home 3D printing in reducing energy and resource usage—when plastic is the best material for the job.
Whether for a children's block or a hand-held citrus juicer, wood is as a long-lasting and durable option as plastic, in practical terms. While wood sourcing has plenty of environmental concerns of its own—deforestation, habitat loss, et cetera—compared to plastic it has much lower greenhouse gas emissions.
It's all well and good, and necessary, to compare resource and energy use for plastic manufacturing, in determining which is the overall greener option, a broader view is needed—including asking questions about when is plastic the most appropriate option and when another material is better.