Circular economy 3D printing: opportunities to improve sustainability in AM

The circular economy is a concept that seeks to make optimum use of resources in order to avoid waste.

A recent flurry of sustainability announcements from 3D printing firms have revealed new eco-friendly materials, innovative methods of repurposing waste, and the launch of new projects seeking to reduce additive manufacturing’s environmental footprint. 

3D Printing Industry spoke to Emma Fromberg, Course Director at the Cambridge Institute for Sustainability Leadership, and Marta Redrado Notivoli, Project Coordinator of EU-funded research initiative BARBARA and chemical engineer at the Aitiip Technology Center, to garner insights into the state-of-play of circularity within the 3D printing industry, and where opportunities lie for circular economy processes to be applied within the sector going forwards.

Renewed efforts to combat climate change have lately been echoed on a much broader scale too, with US President Joe Biden committing the US to slash emissions by half by the end of the decade, and UK Prime Minister Boris Johnson urging world leaders to “get serious” ahead of United Nations (UN) climate talks later this year.

While such calls for environmental action appear to be getting louder, the failure of both government and industry leaders to match their words with action when it comes to sustainability is unfortunately nothing new. In a similar vein, while additive manufacturing is often considered a more sustainable manufacturing technology than others, according to 85 percent of respondents to a survey by 3D printing software provider Materialise, there is an industry consensus that more must be done to avoid greenwashing the technology

“There is no doubt that heaps of these initiatives are not genuinely solving any real issues in terms of sustainability and are merely offering more efficient material use,” says Fromberg. “However, it is often done with the best intentions.”

Circularity refers to an economic system with the goal of eliminating waste and the continual use of resources. The need for further research into how this concept can be fully applied within the 3D printing sector has been highlighted by researchers from the Universidade NOVA de Lisboa (UNIDEMI), who believe greater open-source collaboration between industry partners could eventually provide new methods of addressing the UN’s sustainability goals with the technology.

The principle of a circular economy. Image via Fillamentum.
The principle of a circular economy. Image via Fillamentum.

What is the circular economy?

3D printing has proven effective in recent years at enabling companies to embrace distributed production, and this in itself comes with environmental benefits such as improved process efficiency, less waste, and reduced emissions from transportation. 

However despite these efficiency benefits, there is a growing industry consensus that far more needs to be done to improve the sustainability of the technology than is currently underway. One notion receiving increasing attention is that of the circular economy, and the role 3D printing can play in achieving circularity within manufacturing. 

“As explained in the work on Cradle to Cradle by Braungart and McDonough: sustainability is not about doing less bad – we need to look at how we can do good,” says Fromberg. “It is a narrow focus to only look at the efficiency and agility of production only. We are then just using less energy and fewer materials.

“Just using less of everything is not going to be enough to address our economic, societal, and environmental crisis.”

The injection molded fuel-line clips. Photo via Ford.
Ford uses recycled 3D printing material for injection molded fuel-line clips for use on its Super Duty F-250 trucks. Photo via Ford.

Ongoing circular economy projects within AM

Within the 3D printing sector alone, there are various initiatives currently underway to develop closed-loop manufacturing processes that reuse and repurpose waste materials. Within the automotive sector, Groupe Renault is creating a facility entirely dedicated to sustainable automotive production through recycling and retrofitting vehicles using 3D printing, while Ford and HP have teamed up to recycle 3D printing waste into end-use automotive parts.

One notable project that is addressing circular economy 3D printing is BARBARA (Biopolymers with Advanced functionalities foR Building and Automotive parts processed through Additive Manufacturing), a Horizon 2020 project that brought together 11 partners from across Europe to produce bio-based materials from food waste suitable for 3D printing prototypes in the automotive and construction sectors.

Upon concluding four years of research in October last year, the project successfully developed eight new bio-based materials suitable for fused filament fabrication (FFF) 3D printing, created by extracting natural dyes, bio-mordants, antimicrobials, and essential oils from pomegranate, lemon, almond shell, and corn and processing them into filament spools.

“Additive manufacturing can be used not only for prototypes but also as an opportunity to customize specific pieces,” says Redrado Notivoli. “In BARBARA, we have developed aesthetic details to technical parts.”

BARBARA reached a technical readiness level (TRL) of five in October, and the consortium is currently planning to apply for national and European funding to reach TRL nine, which would involve upscaling the results of molecule extraction, extrusion and filament materials, and developing technology such as the consortium’s 3D printing heading device. 

So far, the initiative has contributed to the growth of related industries within the bio-economy and circular economy European framework, and the next stage will be to scale up the project’s processes to a semi-industrial level.

“Regarding circular economy, the use of filament spools means no material waste,” Redrado Notivoli continues. “Additive manufacturing is a technology which doesn’t consume much energy, we can say it is a clean process. Residues such as plastic and fibers are used for manufacturing new biopolymers, while waste from other plastic transformation processes is reused in the form of pellets for 3D printing.”

According to Redrado Notivoli, the key benefit for 3D printing companies that embrace circularity within their own processes is waste as a resource.

“There is no waste,” she explains. “It is transformed into resources. This also means the growth of industrial synergies between additive manufacturing companies and others that could be suppliers of resources, such as waste coming from plastic, metal, agriculture, ceramics, and so on. This will imply long-term the reduction of raw material costs.”

Complete fascia prototype by AITIIP. Materials used (left to right): lemon pigment, lemon fragrance, almond shell, pomegranate pigment. Image via BARBARA.
Complete fascia prototype by AITIIP in the BARBARA project. Materials used (left to right): lemon pigment, lemon fragrance, almond shell, pomegranate pigment. Image via BARBARA.

New circular economy materials

In addition to the projects mentioned above, substantial work is also underway to develop methods for more sustainable material production and improve the efficiency of related processes.

For instance, Amsterdam-based 3D printing filament vendor Reflow has released a range of eco-friendly ‘Seaglass’ translucent materials made from locally sourced plastics, while Spain-based 3D printing materials producer Recreus has launched a flexible TPU filament that is 100 percent recycled and made up of waste material from the footwear sector.

Elsewhere, circular 3D printing materials have also been developed from more obscure sources, including lignin from plant cell walls, water bottles, landfill-destined waste, and even termite and boring insect refuse.

According to Fromberg, however, focusing on materials efficiency as a stand-alone solution to improving sustainability both within the 3D printing sector and beyond, is not enough.

“I would say that it can be counter-productive to overly focus on efficiency in the sustainability debate,” she explains. “Why don’t we ask ourselves: what do we want more of? I am interested in 3D printing and digital fabrication because it has the unique feature of cutting out large-scale operations and factories as a means of production and gives back individuals and communities a way to engage in the production, repair, and maintenance of their products.

She continues: “Also in the work of Materiom by Alycia Garmulewicz and Liz Corbyn, there is an interesting field of possibilities opening up around using hyper-local (natural) materials for digital fabrication. All of these ideas together might help us to re-image a resilient and democratic system for production.”

Reflow’s sustainable line of six rPETG materials is made from locally-sourced plastic and inspired by the environment and its ‘natural wild beauty.’ Photo via Reflow
Reflow’s sustainable line of six rPETG materials is made from locally-sourced plastic and inspired by the environment and its ‘natural wild beauty.’ Photo via Reflow

Potential to develop further circular economy processes in AM

When asked where she foresees the greatest opportunities for successful circular economy processes to be applied within the 3D printing sector, Fromberg stated that additive manufacturing technologies have the potential to create a “variety of opportunities” for rural areas and emerging economies, in particular.

“Accessibility of means of production and the economic opportunities that are accompanied by the distributed nature of these technologies could have a profound impact on these areas, adding to equality, working conditions, and social fairness, for example,” she says. “I find this part of the discussion is often overlooked since the AM debate seems to be mostly based in Western urban regions and about materials efficiency.”

However, she offers, there are many benefits to urban areas in Western urban regions beyond just materials efficiency: “Around Makerspaces and FabLab for example that can connect communities and support individuals to keep their products at a high value at all times.

“Combining these types of spaces with tool libraries might also be a way to increase the utility of already existing products whilst connecting them to convenient ways to repair and maintain them.”

The Freiburg researchers used a DIW 3D printing technique (pictured) to test their novel biomaterial. Image via Lisa Ebers, Freiburg University.
Researchers from Freiburg University used a DIW 3D printing technique (pictured) to test their novel environmentally-friendly wood-based 3D printing material. Image via Lisa Ebers, Freiburg University.

3D printing: Sustainable or not?

While new ‘eco-friendly’ materials and improved circular production processes should be championed and encouraged, sustainability in additive manufacturing needs to be considered and applied across all areas of the production system in order to spark effective and tangible change, Fromberg suggests.

“Business managers, designers, engineers, salespeople: they are all used to looking at their own part when a service or product is being rolled out – not the wider system of the production and the use of the product and who benefits from it,” she says. “More effective and genuine sustainable solutions require all these stakeholders to work together and look at the sustainability issue and the solution holistically.”

Indicating that individual triumphs aren’t enough to make the sustainability strides the 3D printing sector desires, Fromberg offers that a much greater collaborative approach between all levels of the supply chain is necessary.

“Even if you would not emit any carbon emissions at all, I would consider it not sustainable if you do not explore how everyone and everything can benefit from whatever you produce,” she explains. “I am looking forward to seeing real creative solutions that celebrate the unique features of 3D printing and digital fabrication in this space.”

It seems fair to surmise that while the development of new eco-friendly materials and the launching of various projects seeking to reduce additive manufacturing’s environmental footprint are positive steps in the sector’s march towards greater sustainability, there is still a long way to go before 3D printing becomes a fully circular manufacturing technology. 

For this to become reality, it will require all parties active within the design and manufacturing process and supply chain to play their part in achieving a sustainable production model beyond simply maximizing process and material efficiencies.

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Featured image shows complete fascia prototype by AITIIP in the BARBARA project. Materials used (left to right): lemon pigment, lemon fragrance, almond shell, pomegranate pigment. Image via BARBARA.