A big change is coming in the way we look at sustainability in additive manufacturing. The challenge has always been what to do with the waste PA12 powder that inevitably results as a byproduct of the process.
But as Rosa Coblens, VP of Sustainability and Communications at Stratasys maintains, if this waste could be diverted from landfill and reused to make further parts, the manufacturer would benefit from substantial economical efficiencies, while at the same time reducing carbon in the supply chain and streamlining delivery frameworks.
When any artifact is made with the 3D printing process, there is waste. Put simply, any powder that has been processed by the AM machine but has not become part of the printed structure "is no longer virgin powered and is waste." But with the new SAF ReLife technology from Stratasys, “we can now take this waste, mix it with virgin powder and create new parts.”
Coblens explains that Stratasys’ SAF (short for ‘selective absorption fusion’) ReLife 3D printing technology is used in the application of repurposing waste PA12 powder from powder bed fusion printers, including high-speed sintering, SLS (selective laser sintering) and jetting build processes for use within the Stratasys H350 printer.
“This sustainable solution helps customers produce high-quality surface finished parts with powder that would otherwise be considered waste. It can significantly lower the cost-per-part for customers, improve their material efficiency, and reduce their overall carbon footprint per build.”
Stratasys has more than three decades of leadership in the polymer AM sector across “the full gamut from rapid prototyping to short-run manufacture: from software to materials, the full ecosystem for your 3D printing needs.” Coblens says that as the offering has shifted from prototyping to industrial solutions, markets served have broadened to include aerospace, defence, automotive, consumer goods, healthcare and medical. She says the organisation’s corporate mission is to empower its clients “to create without limits for a personalised, economical and sustainable world, operating at the nexus of profitability and sustainability.”
Central to this approach is the philosophy of ‘mindful manufacturing.’ Coblens accepts that while industrial processes are resource intensive, this should not be an obstacle to planning production with environmental considerations in mind: “We can make processes better and not repeat what we have done over and over.
"Starting from the source and using all of the unique properties of AM – unique geometries and durability for example – you can usually reduce carbon. We are not trying to replace manufacturing, but we are working with our customers to see where we can inject AM into their business in a meaningful way.”
According to Coblens, there’s a commonly held misconception about AM that “plastic is bad, and recycling is the solution for everything that is sustainable.” But, she explains, this is not always true because “if the plastic part will last for ten years and the previously implemented part lasted for three, you’ve saved seven years of supply chain. So we understood that we needed to address the customer’s waste in their product cycle: the powder is the waste.”
SAF ReLife was beta tested by 3D-pinted industrial parts specialist Wehl Green in trials utilising its SLS waste. The company came back saying that it had recorded 20 per cent savings in total cost per part along with “a substantial reduction in waste by turning unused powder into functional parts through a repeatable process using SAF technology.”
Wehl Green also noted that with the raw material already on site, they were able to turn around new parts in 48-hours, reducing delivery time and increasing customer satisfaction. As Coblens say, reusing powder already to hand means “you’re not ordering raw materials. You’re not transporting them. You’re not processing them.”
It also lessens the requirement for “having to pay someone to take away waste from your factory. This could be hundreds, thousands of kilograms, depending on your production rate. This is good news. On the output side you save money, but on the input side you’ve saved the full supply chain.”
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The question hanging over the re-use of PA12 powder in AM is whether it retains the integrity of the virgin material. As with many aspect of 3D printing, this is an area of continual research with Stratasys committed to finding answers to questions related to how many times powder can be reused, and what are the optimum ratios of virgin-to-waste powder needed to produce certifiable quality.
The manager and co-founder of Wehl Green states that beyond cutting manufacturing costs, the SAF ReLife trials have produced “parts that meet strict industrial specifications. It’s a game-changer for our competitiveness. This circular economy approach has reduced our environmental impact while maintaining top-tier product standards.”
To determine the environmental impact, Stratasys partnered with Fraunhofer IPA and conducted a third-party Life Cycle Assessment (LCA) to validate the environmental benefits of SAF ReLife. The study revealed that repurposing PA12 waste from powder bed print processes in SAF production can reduce carbon footprint by up to 89 per cent, compared to standard production with polyamide 12 material.
Chantal Rietdorf, Research Associate at Fraunhofer states: “Our life cycle assessment demonstrates that Stratasys’ SAF ReLife PA12 solution can reduce the carbon footprint of the reference print job by 43 per cent with the German electricity mix, and by as much as 89 per cent when powered by renewable energy sources, compared to standard PA12.”
Coblens thinks that the AM industry has come a long way since the days of rapid prototyping in the 1980s, using stereolithography techniques that painstakingly produced 3D objects layer by layer in what was (by today’s standards) a not-very-rapid process. In the decade she’s been with Stratasys, “we’ve jumped leaps and bounds across all of the different technologies.”
But, there is still a way to go before AM is delivered at scale to large organisations: “and the key to this is software.” She explains that the Stratasys offering centres on “a whole software suite for customers” powered by GrabCAD and OpenAM that will enable “manufacturers to seamlessly add new capabilities, run operations efficiently, and scale their additive manufacturing with confidence.”
Coblens illustrates her point by turning to the global automotive market: “You’re an automaker wanting to print spare parts instead of keeping inventory all over the world.
"You can have files downloaded from the cloud to wherever production is taking place.” But to do this successfully, “you need repeatability, reliability, high quality. I think that AI will support this leap forward, and it will take off in a big way.”
As a parting thought, Coblens reiterates that for AM, the only way is up. At the moment she says, “probably ten per cent of what’s on your office desk is 3D-printed.” But over the next decade that figure could rise to 50 per cent. “As the use cases become more repeatable and more at scale” AM will become ubiquitous in daily life and “part of the factory of the future.”
