Dartmouth College, Thayer School of Engineering
PI: Prof. Jeremy Faludi
Collaborators: Yuan Shi
Life cycle assessment enables the comparison of a variety of manufacturing processes based on sustainability metrics. A product's life cycle is broken down in to parts to encompass the entirety of resources used and environmental impacts, including material sourcing, processing, transportation, manufacturing, use, and end-of-life phases. Our group at Dartmouth College investigated the environmental impacts of more sustainable materials and methods of additive manufacturing (AM), and compared them to commercial AM and other manufacturing techniques. Studies showed that improvements to AM are possible, and define best practices for government and industry.
Faludi, Jeremy, Corrie M. Van Sice, Yuan Shi, Justin Bower, and Owen M. K. Brooks. “Novel Materials Can Radically Improve Whole-System Environmental Impacts of Additive Manufacturing.” Journal of Cleaner Production 212 (December 3, 2018): 1580–90. https://doi.org/10.1016/j.jclepro.2018.12.017
Additive manufacturing often has higher environmental impacts per part than traditional manufacturing at scale, but new materials can enable more sustainable 3D printing. This study developed and tested novel materials for paste extrusion printing, and tested materials invented by others. Testing compared their whole-system environmental impacts to standard ABS extrusion, measured by life cycle assessment(LCA); testing also assessed material strength, printability, and cost. Materials were chosen for low print energy (chemical bonding, not melting), low toxicity, and circular life cycle (biodegradable, ideally sourced from waste biomaterial). Printing energy was reduced 75% (from 160 to 40 Wh/part), and embodied impacts of materials were reduced 82% (from 6.6 to 1.2 ReCiPe Endpoint H millipoints/part).Overall impacts per part were reduced 78% (from 27 to 6 ReCiPe Endpoint H millipoints/part), including embodied impacts of the printer itself, in a maximum utilization scenario. Results were also compared to previous studies of seven different 3D printers of various types. More than ten material recipes were tested, and mica with sodium silicate showed the best print quality. Strength and print quality did not approach ABS, but material cost was cut by 50%. Thus, while further development is required, some materials show promise for greener additive manufacturing.
Total environmental impacts of various AM methods, measured in ReCiPe Endpoint H Points per reference part. Impacts in multiple utilization scenarios are given to show the differences for printing one part at a time, continuously printing over the course of a day, or printing multiple parts at once (if possible).
Reference part for comparing environmental impacts of various AM methods. Pictured left, ABS printed by fused filament manufacturing; right, mica composite printed by pneumatic extrusion.