Global trade group Additive Manufacturer Green Trade Association (AMGTA) 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 analysis highlights significant environmental benefits of using binder jetting over traditional metal casting techniques.
The AMGTA, which focuses on promoting sustainable additive manufacturing industry practices, commissioned the study. The LCA was conducted by the Yale School of the Environment (YSE) in partnership with industrial 3D printer manufacturer Desktop Metal. Trane Technologies, a US-based “climate innovator,” also collaborated as part of the project.
To determine the comparative environmental impact of binder jet 3D printing versus metal casting, the team analyzed the production of a steel scroll chiller in an HVAC system from Trane.
The preliminary results showed a 38% reduction in greenhouse gas (GHG) emissions through the binder jetting process. This reduction was primarily driven by reduced energy demand during the production phase.
“Prior to this project, uncertainty about the life cycle emissions of binder jetting versus conventional manufacturing approaches was a barrier to AM adoption,” commented 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.”
Sherri Monroe, the AMGTA’s Executive Director, added that “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. 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.”
How was the LCA conducted?
The AMGTA commissioned the LCA in 2021 to better understand the potential for binder jetting to replace traditional sand casting as a more sustainable production method.
Conducted over a two-year period, the study analyzed the cradle-to-gate manufacturing life cycle of a scroll set. Comprising a fixed scroll and orbiting scroll, this scroll set was manufactured by Trane Technologies as part of an HVAC (heating, ventilation, and air-conditioning) system.
Taking place at Trane’s New Mexico facility, the study evaluated a traditional casting process followed by machining, plating, and finishing. Additive binder jetting was then used to 3D print, cure and sinter the same scroll set design. The same plating and finishing steps were utilized in both production processes.
Key takeaways from the analysis
Upon comparing these two manufacturing methods, the team found that there was a 38% reduction in GHG emissions from additive manufacturing compared to the traditional casting-based process.
However, the study noted that redesigning for lightweighting with a lattice-type structure ultimately had a “negligible” impact on limiting GHG emissions. This is because the majority of the electricity was expended on the 3D printing, curing, and sintering steps which would not be impacted by lattice type structures. The overall dimensions of the part, and the efficient use of 3D print volumes, was said to have played a more significant role than lightweighting.
Overall, the study suggests that a 10% mass reduction in the scroll set would lead to a 1% reduction in GHG emissions. Yet, the LCA does claim that lightweighting may offer environmental benefits in the use phase, something which was not assessed in this study. Additionally, production volumes were highlighted as playing a significant role in GHG emissions of the 3D printing process. This especially relates to less efficient use of build volumes and small batch operations.
The LCA also highlights that the energy mix at the manufacturing facility, and whether that energy grid was produced via sustainable means, had a “significant impact on GHG emissions.” It was noted that production in a sustainable energy location does provide environmental benefits for both manufacturing processes. However, the difference in environmental impacts between the two methods “diminishes” as the energy mix becomes more “green.”
The impact of material production was also assessed in the LCA. The study found that the environmental impacts of source powder production were approximately twice that for casting steel. However, this increase represented a small proportion of overall GHG emissions, and therefore played an “insignificant” role in the overall findings.
“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,” commented Jonah Myerberg, Chief Technology Officer at Desktop Metal. “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.”
Additive manufacturing and sustainability
Earlier this year, KIMYA published a LCA for its PETG filaments. This analysis concluded that the company’s recycled PETG filaments can help to reduce CO2 emissions by up to 35%, compared to their non-recycled counterparts. This LCA was conducted in conjunction with Greenly, a Paris-based accounting platform which seeks to reduce the carbon emissions of its users. It is hoped that these findings will encourage users to favor recycled filaments over less sustainable options during 3D printing.
In the metal space, it was recently announced that North Carolina-based titanium developer IperionX had agreed to supply Ford with 100% recycled, low-carbon titanium. This Scope of Work agreement forms part of the two companies’ ongoing collaboration to design, test, and 3D print titanium components for future Ford Performance production vehicles.
A recent LCA conducted by EarthShift Global found that the carbon footprint of IperionX’s titanium is over 90% lower than that of competing titanium powders produced using plasma atomization.
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Featured image shows Desktop Metal’s binder jet 3D printing technology. Photo via Desktop Metal.
