Polymer supplier INEOS Styrolution has developed an experimental styrenics-based 3D printing powder which could result in energy savings of 67% when compared to 3D printing with traditional PA12.
The impressive figure (which takes into account the whole life cycle) is the result of almost three years of testing as part of the company’s PolySLS project, which was funded by the German Ministry for Economic Affairs and Energy. PolySLS officially concluded in November of 2020, and was aimed at developing a novel styrene-based polymer powder for the SLS 3D printing process, with a key focus on energy savings and environmental sustainability.
Yvonne van Veen, Market Innovation Strategy Director at INEOS Styrolution, states, “With the additive manufacturing industry growing at very high rates, we are excited we have developed a material that not only contributes to energy saving and sustainable production but also is an easy material to handle in the printing process.”
The sustainability of polymer-based SLS
Selective laser sintering, or SLS, is a powder bed fusion technology that uses high power lasers to melt raw materials into solid layers. According to a recent life cycle analysis study conducted by chemical specialist BASF and software developer Materialise, around 50% of the powder used in SLS reportedly becomes waste. While recycling used powder is possible, the practice often results in issues that make 3D printed parts unsuitable for performance-dependent engineering applications.
A core issue is a surface texture problem known as the ‘orange peel’ effect, whereby the cooling of the powder once it leaves the build chamber causes shrinkage. This is often remedied by mixing it with fresh powder, but this goes against the sustainability trying to be achieved by recycling in the first place.
Despite its shortcomings, 3D printing is still largely hailed as ‘sustainable’. A recent Materialise survey indicated that 76% of manufacturers believed that additive manufacturing was a more sustainable method of production than its conventional manufacturing counterparts.
In truth, the sustainability of 3D printing is not a simple yes/no dilemma. In fact, according to a university research paper commissioned by the Additive Manufacturer Green Trade Association (AMGTA), 3D printing has a higher average carbon footprint, per kg of material processed, than conventional manufacturing. This is largely dependent on part geometry and production volume, however, as it is preferable to mass-machine simple solid cubes, whereas it would be best to 3D print a small batch of complex lattices.
A similar conclusion was reached by researchers from MIT, Yale, and the University of Nottingham. Again, part geometries that lent themselves better to the additive process were seen to reinforce 3D printing’s reputation as a ‘green technology’.
Styrenics-based polymers for 3D printing
Looking at the results of INEOS’ study, around 25% of the energy savings were as a direct result of lower process temperatures, and shorter heating and cooling phases. As such, the time needed to complete print jobs was significantly reduced. Specifically, the company’s styrene powder had an average processing time 7.5% shorter than that of PA12. When material production was taken into account, however, the total energy savings almost tripled to 67%, giving an indication as to just how impactful powder recycling can be when it comes to sustainability.
Bianca Wilhelmus, Global Application Development Manager at INEOS and Project Lead for PolySLS, sees great potential for the styrene material family: “Styrenics-based materials continue to amaze me. Even 90 years after the first production of polystyrene, there are still new things to explore. Styrenics-based materials have incredible, beneficial properties.”
As it stands, the new material has only seen use within the PolySLS project. INEOS has stated that future commercial availability will be dependent on the results of further testing, product demand, and production capacity.
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Featured image shows styrenics-based polymer beads manufactured by INEOS. Photo via INEOS Styrolution.