In the future, if you need a new smartphone case, you might not have to drive to the store and purchase one that comes wrapped in even more plastic. If you have a 3-D printer, you can purchase an entire spool of plastic filament for about $30 that could make 100 smartphone cases.

The printers usually use two different types of plastic: ABS or PLA. Each type of plastic has its advantages for printing, but there are disadvantages as well. Not only does melting plastic smell terrible, but there is also the potential toxicity of airborne, ultrafine printing particles. And then there’s the issue of what to do with failed products. What if the first smartphone case doesn’t quite fit the phone, or the second case has edges that are too sharp?

While 3-D printing has the potential to lower the energy costs of manufacturing, it also raises questions of sustainability if the plastics cannot be biodegradable or at least easily recycled. Eventually, we could all just become our own small-scale, inefficient factories. But some 3-D printing companies are already working to ensure that is not the case.

Type A Machines, a 3-D printer manufacturer, has sold about 300 of its products, which cost $1,695 a piece. The company only sells PLA filament, which is cornstarch-based, because “ABS is not exactly a sustainable plastic,” said Andrew Rutter, founder and CTO of Type A Machines.

“ABS is a concern because it contains known carcinogens,” he said. “And anyone who’s used a desktop printer is aware that ABS, if nothing else, smells quite unpleasant.”

Even so, PLA requires heavy chemicals to be processed into printable form and takes a long time to break apart naturally. “At the moment, there is no good way to dispose of it,” said Johann Recordon, a project manager at swissnex San Francisco. “We find it here in California under the plastic recycling symbol 7 and it should be compostable, but I'm not sure how well it is actually disposed of once it reaches the recycling facility.”

Recycling Is the First Step

The smell of printing plastic, along with the potentially toxic particles emitted by 3-D printers, is something that Tyler McNaney, CEO and founder of the filament-extrusion machine company Filabot, hopes to resolve.

“We’re working on a solution for that,” McNaney said. “We’re building filters that people can 3-D print that will filter the air.”

McNaney’s 3-D printer air filter is one of his most recent ideas, but Filabot’s first product attempts to tackle the issue of sourcing filament. Filabot’s Wee is a filament maker that uses plastic pellets to extrude the type of plastic that a 3-D printer can use.

The Wee was just released earlier this month, and not only are the plastic pellets significantly cheaper than buying ready-to-use filament, they’re also recycled. Everything Filabot is working on is based on recycling, and it started with McNaney’s concept of reusing the plastic from failed 3-D printed prototypes. In order to do that, he needed something to turn the prototypes back into filament: a grinder.

“The real point of the grinder was to recycle bad prints,” he said. “But then we realized you could put plastic bottles and other stuff through it too.”

McNaney started putting all kinds of plastic through the grinder, which is not available for purchase yet. He said it could be available as early as later this year.

“We’ve been grinding up Legos to use for color,” he said, referencing the spools of colored filament for sale on the Filabot website. “Say someone places an order for red filament. We use one pound of ABS and then add about 2 percent to 5 percent of the weight with Legos to color the filament.” And yes, the Legos are used, not new.

“Once you can recycle an item and turn it into something useful, it’s not being thrown away,” he said. “We have a five-gallon bucket full of failed prints. Waste districts don’t know what to do with them. With our grinder, we can grind them up and make filament. Once we can extrude different types of plastic, we can use milk jugs, soda bottles, shopping bags.”

He said that PVC plastic and vinyl do not work in the Filabot Wee or in any type of extruder, because they emit toxic fumes when melted.

The Search for Sustainable Plastic

In May 2013, swisscleantech and StartupNectar partnered with swissnex San Francisco and held a global forum to find out the potential 3-D printing has to be environmentally friendly. Representatives from Bangalore, Shanghai and San Francisco-based companies spent six days looking at scenarios and addressing concerns such as quality, speed, durability and sustainability.

“The short answer to the material side of the question ‘Can 3-D printing go green?’ is, considering the discussions we had during the forum, not really, not right now,” swissnex’s Recordon said. “Finding a groundbreaking green printing material requires putting together some really difficult aspects.”

Ideally, a sustainable filament would be biodegradable to the degree that it could break down naturally in a matter of days. It would also need to be reusable so a smartphone case that didn’t come out quite right could be fed back into the machine and reprinted.

Until a sustainable filament is developed, recycling prints might be one of the best options for anyone looking to keep their 3-D objects out of landfills.