Interview first published in the March/April 2022 issue of 3D ADEPT Mag, produced in collaboration with Evonik. Roles, products and outlook statements reflect that period.
The time I have already spent in this industry makes me realize that the power of an additive manufacturing process lies in its ability to transform a material. This is in any case what is usually demonstrated in almost all the applications that are highlighted across industries. Today, with the growing popularity of 3D printing for manufacturing all sorts of items, material producers have a lot of work to do as they need to deal with new industry trends, qualification and certification. We caught up with Evonik’s Head of Additive Manufacturing Innovation Growth Field, Dr. Dominic Stoerkle, to discuss the development of materials in line with these stakes and how they interplay with automotive 3D printing applications.
The more AM is being challenged to foster industry 4.0, the more it raises debates in the way products are manufactured. In our still maturing industry, the technology increasingly holds promises for green benefits.
AM can facilitate local production, reduce some material losses or enable new geometries. These benefits depend on the material, process, energy use and post-processing. Machining may still be necessary, and feedstocks are not automatically sourced locally. Evonik’s Dr Dominic Stoerkle places these questions in a life-cycle perspective:
“Sustainability is the core element for being successful in the future. In addition to other factors, such as efficient production or reusability of materials, sustainable feedstocks are also an important part for additive manufacturing on its way to evolve into an industrial-scale production technology. However, it is important to look at sustainable feedstocks from different angles. We select the feedstocks based on comprehensive life cycle analysis considering carbon dioxide reductions together with other important factors such as water consumption and land use. At Evonik, we follow the eCO-line approach: We are working with our value chains to substitute fossil feedstocks with renewable and circular feedstocks such as end-of-life tires and we use renewable energy for production. In this way, the overall eco-balance of our products can be significantly improved along externally certified proceedings without changing material property profiles.”
Evonik develops additive manufacturing materials under its INFINAM® brand and also invests in the sector through its venture-capital activity.
This interview considers polymer materials, automotive applications and the developments Evonik envisaged in 2022.
3D-printed plastics can serve prototyping, tooling, customisation and selected end-use components. Cost, lead time and properties must be evaluated for each application. Common process families include selective laser sintering (SLS), fused deposition modelling (FDM) and resin photopolymerisation.
Why the focus on plastic materials for automotive applications?
Automotive components may face mechanical loads, heat and chemical exposure. Selected polymers can meet such requirements while reducing mass, but suitability depends on the component and its service conditions.
Polymers offer useful design freedom in vehicles. Their recyclability depends on composition, collection, sorting and available processing routes. A recycling rate for the whole vehicle cannot establish the rate for its 3D-printed polymer components.
Stoerkle describes Evonik’s offering and experience with these technologies below.
“Our polymer materials have been used in additive manufacturing for more than 25 years; we offer both the broadest range of technologies to produce powders and a very wide range of chemistry platforms to design photopolymers”, the company’s representative lays emphasis on. The company explains that its proven polyamide 12 powders are well suited for reliable and reproducible production of a large number of plastic parts. “With Polyamide 613, a stiff and ductile powder material with higher heat deflection temperature, we offer an alternative polymer optimized for all challenges in automotive applications – with similar good processability in Powder Bed Fusion printers as our polyamide 12.
For applications that require high temperature and chemical resistance, our PEEK filament for the FDM technology is the material of choice. With respect to our photopolymer products, I want to mention the high-strength resin INFINAM® ST 6100 L which resembles glass filled nylon and INFINAM® RG 3101 L, an ABS like material. Both exhibit long-lasting thermomechanical performance and can be used above 70°C, the ST material above even 120°C, which is mandatory for automotive applications. In addition, we launched INFINAM® FL 6300 L together with the Austrian company Cubicure, a polyester-based elastomer photopolymer with unseen durability and fatigue behavior”, Stoerkle notes.
The temperatures in this statement are supplier claims, not a single requirement for every automotive component. Load, exposure time, ageing and test method must be specified when qualifying an application. Evonik introduced RG 3101 L and FL 6300 L in its 2021 announcement.
Speaking of applications that these materials can drive, the Head of Additive Manufacturing Innovation Growth Field explains that the variety of applications depends directly on the materials mentioned and their properties. Non-visible components without safety requirements can be 3D printed from polyamide 12, as well as covers and grids for air-condition where a huge knowledge about postprocessing of the surface is already available. For more advanced applications, the polyamide 613 powders with higher heat deflection temperature are suitable. According to Stoerkle, Evonik’s recently introduced elastomeric resin INFINAM® FL 6300 L is the right material for dampening applications and cable holders, whereas the high-strength resin INFINAM® ST 6100 L can be used for connectors and clips.
In the IEA’s Global EV Outlook 2021, the Sustainable Development Scenario envisaged a worldwide stock of 230 million electric vehicles in 2030, excluding two- and three-wheelers. This was a scenario for vehicles in use, not annual sales or a guaranteed outcome. That outlook motivated the development of materials and processes for electric mobility.
Battery performance, charging and thermal management are among the development priorities for electric vehicles. Material producers seek solutions compatible with manufacturing, assembly and operating constraints. Stoerkle outlines Evonik’s work:
“To increase the range of electric cars, higher battery efficiency is needed. The next generation cooling systems with new cooling agents are required. Both monolayer and multi-layer system solutions developed by Evonik for the pipes of the cooling system can fulfill the need for a longer battery duration and perform well with different cooling agents. Moreover, we are developing a material that will meet one of the highest requirements in e-mobility: the V0 flame retardancy of polymers without compromising the chemical and physical properties of the materials over a wide temperature range.”
V-0 is a classification under UL 94 plastics flammability tests conducted under defined conditions. It does not by itself certify the fire safety of an entire battery or vehicle. The cooling solutions discussed here are not necessarily 3D-printed.
The goal here is to improve batteries with reduced weight and dimensions, that have efficient temperature control.
Other material families, including polycarbonates and adhesives, can contribute to battery systems. Their role and performance depend on the design and manufacturing process.
Moving forward…
To close the interview, Stoerkle describes Evonik’s 2022 roadmap for powders, photopolymers and validation on different printing platforms:
“Thanks to our strength in innovation, years of expertise in polymer chemistry for AM and strong industry partner network, Evonik knows how to develop and manufacture materials and to scale processes for serial production. We use this expertise for the long-term development of new materials for 3D printing serial applications.
If we consider the powders segment, new processes like the ones developed by Evolve or Nexa3D require new, tailor-made powders. For both, the STEP and the QLS technologies, we jointly develop ready-to-use materials from our existing polymer powder portfolio like polyamide 613 for higher temperature applications or our INFINAM® TPA elastomer for flexible parts to make them suitable for those very exciting processes.
Lastly, [throughout this year], you will see our photopolymers appearing on a lot of major printer platforms. Our material validation focus here is on printer systems which promise to bring down total-cost-of ownership and allow for real industrial part production.
We do encourage everyone to contact us to develop and implement further applications with additive manufacturing.”
This exclusive feature has been written in collaboration with Evonik.
This interview was first published in the March/April 2022 issue of 3D ADEPT Mag.
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