How 3D printing can revolutionize sustainable design
As a sustainable innovation leader at a technology company, I'm often asked about the implications of recent advances on sustainable innovation. In this article I'll highlight the potential of 3D printing to revolutionize sustainable innovation.
Three-dimensional printing — or more specifically, additive manufacturing, the term generally used to mean commercial-scale production using 3D printing technologies — is a concept that deserves its geek fandom. But I'd wager that few people have appreciated its revolutionary implications as a sustainable technology. Philosophically, 3D printing is the first technology that has the potential to enable a more biomimetic production model by aligning with one of nature's fundamental tenets: the tendency to manufacture locally. (These and other deep design principles from nature are collectively known as the practice of biomimicry.)
Why additive manufacturing is a shift
To understand why, consider the difference between how an object is traditionally manufactured and how one is produced additively. Traditional manufacturing methods focus on milling a starting blank — that is, removing material until you've achieved the desired shape — or injecting material into a mold. Both types of processes rely on expensive, high-throughput machinery to achieve high economies of scale that minimize costly raw material waste, so such manufacturing is generally performed at a company's main production facility and then shipped around the world. In an additively manufactured product, in contrast, the product is printed layer by layer, with each cross section stacked on top of the one below it. Because this operation can be performed without huge, high-throughput machinery, it can be performed at hundreds or thousands of remote locations — or millions, if you consider the potential of a 3D printer in every household — with near-zero waste.
This hints at a very interesting shift for commercial product makers: They can focus on designing the best product as the source of their intellectual capital, rather than on how the design can be cheaply manufactured. Imagine, for example, if we could purchase the 3D model of an object we wanted to buy, rather than the object itself, and then download and print it in our home 3D printer. By buying this design from an "app store" of 3D objects rather than a brick-and-mortar shop, and printing it ourselves, we've completely eliminated all of the waste of traditional manufacture, as well as 100 percent of the energy and material normally consumed in transportation and packaging — while enjoying a more custom-tailored and convenient shopping experience.
3D printing materials
It's also worth highlighting the materials that are typically used in a 3D printer — surprisingly, here, too, we can find a sustainability story. The most common materials used for the printing of plastic parts are acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA). Both are thermoplastics; they become soft and moldable when they're heated and return to a more solid state when they're cooled. ABS is far from environmentally friendly, but PLA is actually a sugar-derived polymer, so it can be made from plants; most commonly, it's made from corn. (If you've drunk from a clear plastic cup or used a plastic fork marked "compostable" or "made from corn," that was PLA.) Provided that we use ecologically sound agricultural practices, we sustainably could grow the feedstock for all of our 3D-printed objects.
The other beautiful thing about thermoplastics is that they can be re-melted and reshaped into new objects several times (although not infinitely, as their structure eventually will depolymerize). That means that when you're ready to change your toy truck into a toy airplane, you could, in theory, toss it back into the 3D printer to be reshaped into the new object. This gets to one of the biggest sustainability challenges with plastic products today: their end-of-life treatment. Putting plastics into curbside recycling bins seems like an environmentally sound idea (and it's still better than throwing them into a landfill), but once they're trucked, sorted, cleaned and usually commingled with lower-value resins, there's usually not much economic margin to squeeze out of these recycled plastics — one reason why their rates of recycling are so low. In contrast, putting your pure PLA back into your 3D printer eliminates this whole recycling chain — so we can add "end-of-life impacts" along with transportation and manufacturing waste to our list of eliminated life cycle impacts.
Metals also can be made using an additive manufacturing practice called selective laser sintering (SLS), although these "printers" are much higher end. Once these become suitable for casual use, it opens up a whole new category of objects that can be built. Although in theory metal is infinitely recyclable (its simpler crystalline structure does not degrade with re-melting), the grinding steps needed to reprocess the used metal into powder suitable for sintering would require a lot more equipment and energy, and likely would prohibit the recycling of 3D-printed metal objects in the same printer — even a direct SLS printer (which uses a single material powder).
At the doorstep of future usages
True radical innovation occurs not from new technologies, but when those new technologies enable newly possible business models. Take, for example, the cool modular mobile phone concept called Phonebloks. Imagine that you want that new, higher-megapixel cell camera block that they refer to ... so you just buy and download the new block, toss your old one back in the printer and print up the new model in PLA with a metal layer with the electronics sintered on — all powered by the solar panels on your roof. Now, we're starting to approach the manufacturing process used sustainably by nature over the last 3.8 billion years. And someday, your house?