The Greening of Additive

The Greening of Additive
SME Media April 2022
By Kip Hanson

Whether it’s taking out the recycling bin each week, buying an electric vehicle, or keeping our thermostats to a not-quite-comfortable temperature, many of Planet Earth’s inhabitants (those of us fortunate enough to enjoy such conveniences, anyway) are taking steps to reduce waste and energy consumption.

This trend also extends to the manufacturing industry, and nowhere is this more evident than with 3D printing. From service bureaus to equipment providers to environmentally conscious trade associations, additive manufacturing is slowly but steadily going green.

It’s All About the Carbon

Sherry Handel is executive director of the Additive Manufacturer Green Trade Association (AMGTA) in Hollywood, Fla. As the name of her organization indicates, she spends her days thinking about AM sustainability, and hinted that AM might not be as green as some pundits claim.

“You hear all these claims people make about 3D printing being more sustainable than conventional manufacturing, but that’s a very broad statement,” she said. “It depends on the application, what technology and material you’re using, and what you’re comparing it against. As with so many things in this industry, the reality is this: it depends.”

Handel cited the 2020 AMGTA study “State of Knowledge on the Environmental Impacts of Metal Additive Manufacturing,” conducted in collaboration with The Netherlands’ Delft University of Technology. (Read more about the study on Page 12, “Research Eyes Additive’s Carbon Footprint, Payoff.) Its findings support her “it depends” comment and make a strong case for additional research. However, some key takeaways paint a somewhat disappointing picture for a greener 3D printed future, among them the conclusion that “In direct manufacturing process comparisons, AM had roughly ten times higher carbon footprint per kg of material than casting, extrusion, rolling, or wire drawing.”

And yet, there are several silver linings to the grim assessment. One is that additively manufactured parts often enable major performance improvements over those made with legacy processes, particularly in fuel-conscious applications like commercial air travel. In addition, the study suggested that “situations must be found where AM greatly reduces part mass, combines multiple CM [conventional manufacturing] processes, avoids tooling for short production runs, or provides other benefits,” all of which lie in the additive wheelhouse. To this point, the authors compared three different part geometries, each with varying amounts of 3D printing friendliness. The results showed that, given the right design, AM reduced manufacturing-related CO2 emissions by roughly 50 percent compared to the same part made via CNC machining.

Yet as Handel pointed out, this example does not consider potential fuel savings in the field, service life and replacement costs, component manufacturability, part count reduction, supply chain considerations, and numerous other factors that have long-term impacts on sustainability. “There are also a host of innovative alloys and polymers coming out that could swing the needle in AM’s favor, not only for aerospace and automotive but in other industries as well,” she said. “Regardless, it’s obvious that we need detailed life-cycle assessments for a range of additively manufactured products and applications, something we’re actively working on.”

Fresh Powder

John Barnes can speak at great length about additive materials, especially those used in the aerospace industry. The founder and CEO of The Barnes Global Advisors, a Pittsburgh-based consulting firm focused on AM industrialization, Barnes is a graduate of Purdue University’s bachelor’s and master’s programs in Metallurgical Engineering.

He’ll tell you that he and business partner Chris Aldridge once worked for the same service bureau, where they struggled with metal powder consistency while qualifying parts for Airbus. They’ve since launched a new business venture—Metal Powder Works, Sewickley, Pa.—to address what Barnes knows firsthand is a chronic problem with commercially available powders.

What does the quality and consistency of metal powders have to do with sustainability? A great deal, actually. Because Metal Powder Works’ mechanical production process does not rely on gas atomization to produce these common feedstocks, it uses less energy and no industrial gases, both clear wins for the environment, not to mention producing no CO2 while in use. And according to Barnes, particle consistency is much greater, giving manufacturers more usable powder per pound. This serves to reduce raw material waste while assuring more predictable printing outcomes. Consumers can also produce the powder onsite and as needed, easing concerns over powder oxidation and shelf life while eliminating shipping and storage costs (aside from that of the bar stock used to make the powder).

Without going into the technical details, Barnes explained that the invention rethinks powder manufacturing. The system is computer controlled for efficiency and enables the shape and size of the particle to be produced according to the desired specification, rather than sifting through what is produced to match the requirements. “By adjusting the algorithm and the design of the tool, we’re able to control the size, shape, and morphology of the powder and can achieve 95-percent to 100-percent efficiency in a particle size distribution of 20 to 63 microns,” he said. “Best of all, we don’t melt the material or change its chemistry, and we’ve shown potential to use the process for polymeric powders.”

Despite these advantages, there is—quite literally—one small problem. Because Metal Powder Works’ mechanically produced particles resemble “chocolate M&Ms” rather than the spherical peanut M&M shapes created through gas atomization, they pack differently within a metal 3D printer’s powder bed. As such, some adjustments to the printing process and equipment might be necessary. Beta tests have shown, however, that these variables are quite manageable, and Barnes looks forward to commercializing his process over the coming year.

“Lower material costs are obviously a key driver here, but our process is definitely more environmentally friendly and should be easier to qualify besides, further enabling additive manufacturers,” he said. “These are all good for the planet.”

Feeling Blue

But what about the other side of the additive coin, polymer and resin-based 3D printing? Erik de Zeeuw, a project manager and certified manufacturing market manager at Leuven, Belgium-based Materialise NV, offered one recommendation.

He referenced a company press release that states, “with selective laser sintering, the second most used 3D printing technology, up to 70 percent of the powder is downcycled [recycled into lower quality products] or becomes waste.” In addition, “the production of each kilogram of standard PA 12 [nylon] powder generates more than seven kilograms of  CO2.” But by using the company’s Bluesint PA 12 technology and printing with recycled powder, the report claims, these emissions are reduced by 32 percent, eliminating thousands of tons of carbon dioxide annually while simultaneously reducing the amount of powder going to waste.

Compared to the human race’s 40-plus billion-ton annual CO2 contribution, the gains made through Bluesint PA 12, Powder Metal Works, or any other AM technology are drops in the bucket, but significant nonetheless. They indicate what an increasing number of manufacturing companies—Materialise among them—have begun to realize: that everyone must do more to increase sustainability, and these efforts have to start with their own products and services.

“The premise that additive manufacturing is a sustainable technology is one that we don’t necessarily agree with,” de Zeeuw said, seconding what AMGTA’s Sherry Handel suggested earlier. “There’s evidence that this is often not the case, especially now that the market for 3D printing is growing—in some areas, quite massively. Because of this, we’ve become more aware of our environmental impact and have taken steps to measure our carbon footprint.”

Those steps take two forms. The first is corporate in nature and includes the adoption of science-based targets, publication of an environmental policy, and achievement of ISO 14001:2015 certification. Thanks to these initiatives, Materialise expects to cut the 20,300 tons of annual greenhouse gas emissions (as measured in 2019) from its worldwide operations in half by 2025.

Secondly, it will continue to improve its well-known suite of 3D printing software, thereby enabling its customers to reduce waste in their manufacturing processes and be more efficient overall. “Working towards a better, healthier world has always been part of our company DNA,” said de Zeeuw. “And to that point, I’m proud to say that we were one of the first companies to begin asking what we can do to make AM more sustainable. That continues to be our goal as an organization.”

The View From Ventura

Avi Reichental shares those goals. The CEO, chairman, and co-founder of Nexa3D, a Ventura, Calif.-based additive manufacturing solutions provider, he said everyone in the AM industry has a responsibility to implement and leverage the strength of 3D printing throughout each part of the product life cycle. “This means that, from the very beginning of the design cycle and beyond, we must ask ourselves whether there are opportunities to reduce and become more efficient in our processes,” said Reichental. “The answer in most cases is a resounding yes.”

He explained that such opportunities take many forms. Support elimination is an obvious one, as this reduces waste. Product lightweighting through topology optimization is another. But there are also postprocessing considerations, raw material and finished product recyclability, and energy consumption during the build process (which is directly related to part mass). Each has a direct impact on sustainability. And like Materialise, Reichental and the Nexa3D team are also looking at ways to reduce waste internally, including the use of environmentally friendly detergents and solvents for part washing and vapor smoothing.

“I’ll give you another example,” he said. “We’re in the process of launching our XiP desktop printer. Well over a year ago, we made a series of decisions that have made it a much more responsible and sustainable product. One of these was to make the entire printer from aluminum, the most recycled material on Earth. That decision also allowed us to make a more rigid and rugged product that will withstand harsher environments, provide longer life, and reduce the need for repairs and spare part inventories down the road. All of this leads to a smaller carbon footprint.”

With two decades in the AM industry and ongoing leadership positions at numerous 3D printing equipment and software providers, Reichental said he’s learned many lessons over the years, the most important being that there are no easy answers.

“Sustainability has to be a way of life, no matter what you’re making,” Reichental said. “It requires thinking about product life cycles in a very different way. And yes, we’re blessed that—on the surface at least—additive appears to be inherently more sustainable, but not in all areas and not without the required effort. I think this is where, as an industry, we have an opportunity to learn from and with one another to determine how to measure the activities that could put us on a different trajectory in terms of our contributions to reduce global warming.”

Mindful Manufacturing

Stratasys, like Nexa3D, is pulling in the same green direction. “Sustainability is a very clearly defined objective for many CEOs on the planet,” said Andreas Langfeld. “They all have it on their strategic agenda, and they all have a budget assigned to it. Stratasys is no different in this respect.”

The EMEA president highlighted four United Nations’ Sustainable Development Goals as particularly high on the list of the 3D printing pioneers’ many green guidelines, based on feedback from company employees and customers. These are: Responsible Consumption and Production; Climate Action; Industry Infrastructure and Innovation; and Quality Education.  Stratasys is working to set specific benchmarks and goals against each of these SDGs, for example, by reducing printer energy consumption or developing easily reused or recycled materials—and by delivering a message of “mindful manufacturing” to its customers, encouraging them to invest in design processes and products that are more environmentally friendly.

Said Langfeld, “Global Efficiency Intelligence LLC published a report that says 22 percent of all  CO2 emissions comes from international trading of goods and services. That means we have trucks, ships, and airplanes supplying parts from a central hub to different sites across the globe, all day, every day. But by transitioning from traditional manufacturing to additive, manufacturers can produce goods locally and on-demand, eliminating the need to inventory products or ship them across the planet. That in itself presents a huge opportunity for greenhouse gas reduction.”

Langfeld pushes back on those who question additive’s sustainability. Aside from the “print local, print small” capability, AM’s digital workflow reduces product iterations while making the development and manufacturing processes more efficient. Optimized part geometries consume less material than machined or plastic injection-molded components, as does the ability to combine multi-function, complex assemblies into a single 3D printed part. It also eliminates assembly time and potential failure points, reduces work-in-process, improves product performance, and much more. The industry must consider these and other advantages when evaluating 3D printing’s sustainability.

“We deeply believe that AM is a tool for improving people’s lives,” said Langfeld. “You see it in our healthcare innovations, where we are doing amazing things for patients. You see it in terms of the CO2 emissions I just mentioned, and in the development of new, more sustainable materials. But we also have many amazing use cases with companies like Airbus, Siemens, and many more, manufacturers who are adopting 3D printing to change the status quo. Their positive outcomes are proof points for AM being a more sustainable solution when compared to traditional production methodologies. So that’s what’s driving us, and is why we are full steam ahead with spreading the word on mindful manufacturing, with assigning the resources internally to support that, and with delivering the data needed to convince customers that, when it comes to sustainability, additive is a no-brainer.”