Using life cycle assessment to determine if high utilization is the dominant force for sustainable polymer additive manufacturing

Previous studies on the environmental impacts of polymeric additive manufacturing (AM) have shown that higher printer utilization dramatically improves impacts per part—so much so that it might dominate all other interventions if taken to an extreme. High utilization can be both temporal (printing constantly) and spatial (printing many parts at once). In this study, life cycle assessments (LCAs) were performed for an inkjet fusion printer with exceptionally high spatial utilization capacity and were compared to previous LCAs of nine printers printing with eight materials. Comparisons were performed in different utilizations, both temporal and spatial, to determine if high utilization reduces the environmental impact of AM more than other interventions, such as using sustainable print materials. For the inkjet fusion printer, maximum utilization dramatically reduced the environmental impact per part to less than 1% of its impact in lowest utilization; this was below the impacts of other printers in low utilizations. However, when compared in the same utilization scenarios, the inkjet fusion printer still caused a higher environmental impact per part than almost all printers, primarily due to high energy use. The lowest-impact printer used both high spatial utilization and low-impact materials that also enabled a low-energy printing process. Therefore, printer utilization is not the overriding factor and must be combined with energy efficiency and material choice.