Driving circular plastics economy in additive manufacturing

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By its very nature, additive manufacturing is considered a sustainable technology. The sustainable advantages of 3D printing could play an important, even decisive role for producers and manufacturers towards series applications. For material manufacturers like Evonik, living sustainability might not be so self-evident for everyone. But the more aware and transparent the sustainable journey becomes at the beginning of the additive value chain, the more impact these effects will have in the final application. 

Plastics have decisively changed people's lives. Their versatile use is an integral part of our society. As reliable materials for lightweight 3D applications, they help conserve resources. As implant materials, they enhance the quality of life of millions of patients worldwide. As high-performance materials, they enable innovations. “In the future, plastics will continue to improve people's lives in many areas. That's why today's shift from a linear to a circular plastics economy is crucial to safeguarding the quality of life for next generations”, says Dominic Störkle, Head of Additive Manufacturing Innovation Growth Field at Evonik

With a growing emphasis on environmentally friendly manufacturing, the evaluation of the environmental performance of additive manufacturing processes has gained attention. Additive manufacturing offers several sustainable advantages over other processing technologies: The design freedom of 3D components offers enormous potential for novel product developments and improvements in component efficiency and performance. New bionic lightweight structures enable the best possible design of functional elements, which are used as lightweight components primarily in the aerospace and automotive industries. Due to the general principle of all additive technologies of depositing material in a structured way instead of removing it, as in some other processes such as machining, 3D printing materials are used very efficiently. In the recent past, which unfortunately has been characterized by collapsed global supply chains for several reasons, additive manufacturing has been particularly effective: on-demand production of parts organized in a decentralized manner, is now a reality. That’s why 3D printing is often regarded as a sustainable processing technology.

"In our specialty chemicals business with high-performance materials, we don't see the various processing technologies in any sustainability competition," explains Sylvia Monsheimer, who heads the Industrial 3D Printing market segment at Evonik. "People often tend to compare injection molding and 3D printing. But there is room for both on the market, and there are good reasons to rely on one or the other technology depending on the application, such as 3D printing for shorter product life cycles or injection molding for high-volume specialty parts." In addition to the economic arguments, it is impossible to imagine parts production today without ecological aspects. When deciding for or against a processing technology, ecological influences such as sustainability in its many aspects or the various options for recyclability are considered in addition to costs per part.

Material manufacturers bear responsibility

For material manufacturers like Evonik, living sustainability might not be so self-evident for everyone. But the more aware and transparent the sustainable journey becomes at the beginning of the additive value chain, the more impact these effects will have in the final application. Although, establishing an efficient circular economy is a complex thing: every single step in the production cycle must be re-evaluated, supply chains must be reorganized, new materials are needed. Yet material manufacturers bear a great responsibility here because the sustainable result of an application stands or falls with the circular properties of the materials used.

“True circularity is key for being successful in the future. As a pioneer for polymer-based 3D printing materials, Evonik has developed a formula for its PA12 powders to drive circular plastics economy in additive manufacturing”, says Störkle.

Evonik drives circular plastics economy by contributing to both footprint and handprint values. Alongside factors such as production efficiency or the reusability of materials, our circularity approach includes the total life cycle assessments of our materials and their consistent improvement. The specialty chemicals company looks not only at carbon footprint but also at other important factors such as water consumption and land use. Using green energy and renewable or recycled feedstocks for production, Evonik improves significantly the overall eco-balance of its PA12 powder. Furthermore, the company works on end-of-life opportunities for its polymers. 

Improving reusability rates

Evonik already offers its first new PA12 grades which can be reused by only replacing the powder needed for the parts of the previous job which avoids material waste in production according to the group's ZERO WASTE approach. Furthermore new powder materials are being developed to increase their reusability rate during a 3D printing process.

Reducing carbon footprint

In October 2022, Evonik introduced a new grade of PA12 powders with significantly reduced CO2 emissions. The new PA12 powders will replace the previous INFINAM® polyamide 12 materials for all common powder-based 3D technologies such as SLS, HSS or MJF. The new sustainable INFINAM® PA12 powders are produced using renewable energies at the Marl Chemical Park in Germany. TÜV Rheinland has certified the associated life cycle assessments, confirming an improvement in the company's own carbon footprint of almost 50 percent. In the overall life cycle assessment, the comparison of the new sustainable material grade is positive even compared with the castor oil-based polyamides of Evonik's own Terra range.  

Substituting fossil resources with bio-circular raw materials.

Evonik is introducing a new grade of its polyamide 12 powders that is designed to unbound sustainable 3D printing at scale. INFINAM® eCO PA12 is the world’s first PA12 powder material for industrial 3D printing that substitutes 100 percent of fossil feedstock with bio-circular raw material from waste cooking oil in a mass balancing process. The new, ready-to-use powder features a reduction of CO2 emissions of 74 percent in comparison to the castor oil-based polyamides of Evonik's own INFINAM® Terra development grade. Having already launched a new PA12 grade with reduced carbon footprint in late 2022, Evonik is now fully aligning its portfolio of polyamide 12 powders with its circularity approach.

Recycling

In addition, Evonik also work on end-of-life opportunities for polymer-based 3D applications.

Additive manufacturing is an emerging manufacturing technology for parts. With a growing emphasis on environmentally friendly manufacturing, the evaluation of the environmental impact of additive manufacturing processes is crucial for choosing case by case the most efficient and sustainable technology for parts production. Life cycle assessment is an important tool to compute the environmental impacts of 3D printing processes. By developing new sustainable high-performance materials, Evonik wants to drive 3D printing as another important manufacturing technology for series production to coexist with injection molding, extrusion and machining in the future.  For this, the right materials must be used from the start.