Cradle-to-Gate Life Cycle Assessment of Multi-Jet Fusion 3D Printing

Abstract

The rapid pace of growth in additive manufacturing has left significant knowledge gaps in life cycle assessment (LCA) literature, limiting inclusion of sustainability considerations in manufacturing and supply chain decisions. The recent introduction of HP’s Multi-Jet Fusion (MJF) 3D printing technology shows promise as an alternative to other additive and conventional manufacturing methods on the market; however, scarce environmental assessments of MJF exist in publicly available literature. This study fills the gap in current additive manufacturing LCAs to improve decision-making in plastic part manufacturing. This assessment investigated the cradle-to-gate life cycle energy consumption and greenhouse gas (GHG) emissions of HP’s MJF 3D printing technology in comparison to injection molding across production quantities ranging from 100 to 100,000 parts for a plastic product. This analysis leveraged secondary data from various sources, including MJF technical documents, communications with HP representatives, published LCA literature, the ecoinvent 3.5 database, and Argonne National Laboratory’s Greenhouse Gases, Regulation Emissions, and Energy Use in Transportation (GREET) 2019 model. Results of the analysis indicate that MJF 3D printing technology emits less GHG emissions than injection molding with aluminum or steel tooling at quantities up to about 450 and 800 parts, which is 5 to 8 prints jobs for the studied design. 3D printing electricity consumption and material yield are the major factors contributing to MJF’s GHG emissions. Varying the manufacturing facility electricity generation source, post processing time, raw material production life cycle inventory data, and printing speed can substantially alter the GHG emissions breakeven point between MJF and injection molding. Optimum conditions of these variables for MJF could shift the GHG emissions breakeven with injection molding to a point between 5,000 to 10,000 parts. MJF’s lower material yield and requirement for fusing and detailing agent ultimately limit the GHG emissions breakeven quantity with injection molding. Consequently, MJF’s GHG emissions breakeven quantity with injection molding remains one to two orders of magnitude lower than HP’s advertised economic breakeven quantity of 110,000 parts. This study also shows that MJF is slightly more energy efficient and more resource efficient than selective laser sintering, MJF’s peer additive manufacturing process.