3D printing has a complex relationship with sustainability

3D printing promises some sustainability benefits, including creating lighter parts and shorter supply chains, but the overall question of its environmental value is complex.

Manufacturers that rely on traditional manufacturing processes are evaluating 3D printing as a possible approach to meet sustainability goals and reduce carbon emissions.

Traditional manufacturing processes consume large amounts of power, often use wasteful techniques such as milling or cutting, and rely on materials that aren't eco-friendly. Some view 3D printing, or additive manufacturing, as a comparatively more sustainable manufacturing method.

It creates products using materials such as plastics and metals that usually come in the form of powders or filaments. The materials are heated into a liquid and deposited onto a build bed via a nozzle on a 3D printer, and the process is repeated until the product is finished.

But the reality of 3D printing's sustainability value is complicated.

Lighter and stronger parts

One of the main advantages of 3D printing in general is in the nature of the parts that it can produce. Additive manufacturing can consolidate several parts from an assembly into one part that's printed as a whole, said Terry Wohlers, president and principal consultant at Wohlers Associates, a 3D printing research firm in Fort Collins, Colo. This reduces the manufacturing processes, inventory, assembly, labor, certification paperwork and maintenance of the parts, which in turn can reduce carbon emissions.

"GE Aerospace has successfully consolidated hundreds of engine parts to a few," Wohlers said. "This significantly reduced energy requirements and greatly simplifies supply chains."

Reducing the number of parts needed has sustainability advantages, said Luke Rodgers, senior director for R&D at Jabil in St. Petersburg, Fla.

Anything that you can do to reduce the cost of production is always a greener solution because costs are directly related to carbon footprint.
Luke RodgersSenior director for R&D, Jabil

Jabil is one of the world's largest contract manufacturing companies. It primarily uses traditional manufacturing methods, but has been increasingly integrating 3D printing into its processes, Rodgers said.

Parts consolidation reduces costs and resources on the back end and front end, he said. This includes shipping logistics, assembly logistics, cleaning parts, the amount of glue used and time in the factory.

"Anything that you can do to reduce the cost of production is always a greener solution because costs are directly related to carbon footprint," Rodgers said. "Everything that we derive -- whether it's forging in metals to all the raw materials we utilize -- is CO2 related."

Parts made by 3D printing can also be made lighter and stronger than parts made by traditional manufacturing methods, according to Paul Miller, an analyst at Forrester Research.

Lighter parts make lighter machines overall, which means that they can run more efficiently. For example, a lighter car or airplane uses less fuel. And because 3D-printed parts can often be stronger than traditionally made parts, they last longer, thereby reducing waste, Miller said.

Location, location, location

Reducing the supply chain is another sustainability advantage for 3D printing. This is an appropriate strategy for parts that are critical but only needed in small quantities on demand or in remote locations, Miller said. This is useful in locations such as military bases, disaster relief operations or remote mining operations, which traditionally have stocked large quantities of spare parts to remain operational.

"Of course, most of those spare parts don't end up being used," he said. "They're either transported home again or dumped, neither of which are particularly good for the planet."

3D printing is gaining traction because there's more interest in localizing the production of parts, which can simplify logistics, shipping, inventory and holding costs, said Spencer Thompson, lead engineer for environmental technology at EOS, a 3D printing provider.

"For example, you can have a printing operation at an airport hub and not have to either have racks of parts taking up space or have to wait on someone shipping the components that you need if something breaks down," he said. "You can create that at the source, on demand."

Companies should also consider using 3D printing to reduce both the weight and wastage in packaging materials, Rodgers said.

"If you use a single-use plastic, that's probably going into a landfill, so you have to help users select what the right end-of-life is for the packaging material," he said. "There are lots of 3D printing technologies that allow you flexibility to reduce the overall weight for this stuff."

Polymer issues for sustainability

As with many other sustainability issues, the case for 3D printing is not a slam-dunk, according to experts.

Although 3D printing can reduce waste in some cases, it also has waste generation issues, Wohlers said. For example, the polymers for powder bed fusion, a popular 3D printing process, need to be continually replenished with virgin material, which results in 30% to 50% waste, he said.

"Also, all 3D printing processes require extra material to support the building of parts," Wohlers said. "Depending on the specific [additive manufacturing] process, most of this material becomes scrap."

There wasn't much thought about sustainability or environmental health concerns in the history of using polymers as 3D printing materials, Thompson said. EOS is developing new bio-based polymers and carbon-reduced polymers, resulting in materials that can be reused without degrading the components. But it takes a lot of energy to create the materials.

"We melt large vats of powder and blow it through a system to create our powder particles," he said. "Melting vats of material is energy-intensive."

The amount of energy used to power 3D printers and generate the materials is significant and will only get more problematic as 3D printing scales up to larger production volumes, Miller said.

"Printers are energy-intensive, and 3D printing of very large numbers of identical parts is rarely as cost- or resource-effective as using traditional manufacturing processes at scale," he said.

This shows the advantages and disadvantages of 3D printing for sustainability.
Pros and cons of 3D printing for sustainability.

Not a magic bullet

Overall, the sustainability issues around 3D printing are complex, but it can be a valuable tool to solve particular cases, Rodgers said.

"There's no magic bullet for anything, and 3D printing is a piece of the tool set," he said. "3D printing can address some of your problems -- specifically around localized manufacturing, weight reduction, cost reduction. Those are all things that make 3D printing especially advantageous on small-volume production."

The 3D printing processes and technology might not be more sustainable than traditional manufacturing methods, Thompson said, but 3D printing can be used to create more sustainable products. This must be included in the design of the product, and 3D printing allows the design freedom to create parts that are optimized for the system they're going into.

"For example, it might not be more sustainable to use 3D printing to create an optimized aircraft engine bracket than milling it," he said. "But through its use and because it's optimized, you'll reduce fuel consumption down the line, so 3D printing can be more sustainable by creating more efficient tools or components for systems."

Jim O'Donnell is a senior news writer who covers ERP and other enterprise applications for TechTarget Editorial.

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