The Additive Manufacturer Green Trade Association (AMGTA), a global advocacy group focused on promoting sustainable Additive Manufacturing (AM) industry practices, has announced the preliminary results of a life-cycle analysis study titled “Comparative Life-Cycle Assessment: Comparison of Casting vs Binder Jetting for an Industrial Part.”
The study, commissioned by the AMGTA and conducted by the Yale School of the Environment (YSE) in partnership with Desktop Metal, and Trane Technologies, analysed the cradle-to-gate manufacturing life cycle of a scroll set comprised of a fixed scroll and orbiting scroll manufactured by Trane Technologies as part of an HVAC system. Its aim was to determine the comparative manufacturing impact of Binder Jetting Additive Manufacturing versus metal casting.
The study, commissioned in 2021, evaluated a traditional casting process followed by machining, plating, and finishing steps in Mexico. The same scroll set design was also evaluated through a Binder Jetting process of Additive Manufacturing, curing, and sintering followed by the same plating and finishing steps in the same location in Mexico.
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The preliminary results indicate a 38% reduction in greenhouse gas (GHG) emissions through the Binder Jetting process. This reduction is primarily due to reduced energy demand during the production phase. YSE’s researchers concluded that a redesign for lightweighting via a lattice-type structure may not necessarily result in additional reductions in GHG emissions, as the majority of electricity consumed during building, curing, and sintering steps would not be affected by lattice-type structures. The analysis suggests that a 10% reduction in the scroll set’s mass would lead to a 1% reduction in GHG emissions.
The local energy mix at the production site had a significant impact on the lifecycle GHG emissions. In this study, both the traditionally manufactured part set and the additively manufactured part set were evaluated at the same location with the same energy mix. Researchers also evaluated additional potential production locations and their corresponding energy mixes. The findings indicate that the sensitivity to the power grid’s ‘cleanness’ must be considered when comparing AM with traditional processes to ensure a valid conclusion.
While production in a more sustainable energy location provides environmental benefits for both production processes, the difference in environmental impacts between the methods diminishes as the energy mix becomes ‘greener.’ The production volumes also significantly influence GHG emissions in Additive Manufacturing, especially for less efficient use of build volumes and small batch operations.
“Prior to this project, uncertainty about the life cycle emissions of Binder Jetting versus conventional manufacturing approaches was a barrier to AM adoption,” said Kevin Klug, Lead Additive Manufacturing Engineer for Trane Technologies. “With the results of this study, Trane Technologies is in a better position to comprehensively consider AM’s cost, productivity and environmental impact earlier in a product’s design cycle, when risk is lowest, and the potential benefits are highest.”
Key takeaways from the study include:
Significant reduction in greenhouse gas emissions
The additive process resulted in a 38% reduction in greenhouse gas emissions based on Binder Jetting when compared to traditional casting for the parts studied
Importance of energy mix
The study found, as in previous research, that the energy mix of the manufacturing facility at the location of generation, as well as the sustainability of the energy grid used, had a significant impact on GHG emissions
Negligible value of redesign for lightweighting
The study found that the potential benefits of redesigning the scroll chiller for lightweighting using a lattice-type structure were insignificant with respect to GHG emissions; the overall dimensions of the parts being produced and the efficient use of print volumes played a much more important role than lightweighting (it should be noted that lightweighting may provide environmental benefits during the use phase, which is not included in this study)
Impacts of material production
This study found that the environmental impact of source powder production was approximately twice that of casting steel – however, this increase represented only a small portion of the overall GHG emissions and did not play a significant role in the overall findings.
Overall, Binder Jetting Produced a more sustainable part
The dramatic reduction of GHG emissions from energy demand by Binder Jetting versus traditional manufacturing was by far the most important finding of the YSE study
“The release of these findings is significant for the AM industry and for companies in the broader manufacturing sector who are looking for more sustainable production methods,” said Sherri Monroe, the AMGTA’s Executive Director. “With this study, we are able to quantify the reduced energy demand of Binder Jetting versus traditional casting while possibly providing some surprises in the negligible impact offered by lightweighting in this specific use case.”
It was stated that the adoption of Binder Jetting in multiple industries has been a factor behind the double-digit annual growth of Additive Manufacturing over the past decade. This is due to its cost advantages, large volume production capabilities, and potential for improved sustainability.
“We’re delighted to have another piece of independent, third-party research that validates how Binder Jetting is a greener approach to metal part production,” added Jonah Myerberg, Chief Technology Officer, Desktop Metal. “Harmful emissions from traditional metal manufacturing need to be lowered with innovative technology approaches, but manufacturers need sound data – not greenwashing – to make good choices about how they produce their metal products. This new study from Yale, Trane Technologies and AMGTA demonstrates what our team at Desktop Metal has long believed based on our hands-on experience: Binder Jetting is a greener way to manufacture metal parts.”
Kevin Klug added, “Trane Technologies is committed to boldly challenging what’s possible for a sustainable world. That includes designing advanced climate control solutions that can be manufactured and operated with reduced environmental impact. Metal Additive Manufacturing will become an increasingly viable tool in that pursuit, and Binder Jetting’s comparably higher speed and lower cost among AM technologies make it particularly promising for manufacturing HVAC components at relevant production volumes.”
Sherri Monroe continued, “This study in collaboration with Desktop Metal is a clear win for manufacturers like Trane which are exploring more sustainable manufacturing options. Binder Jetting is a proven technology with clear and quantifiable advantages over traditional methods. We appreciate Trane’s leadership in pursuing more sustainable practices, their participation in this study, their willingness to share their processes and data, and interest in sharing this information with the broader manufacturing community.”
Read the preliminary release, here. The full results are expected to be published in early 2024.