Addressing Hazardous Implications of Additive Manufacturing Complementing Life Cycle Assessment with a Framework for Evaluating Direct Human Health and Environmental Impacts

Additive manufacturing (AM) is transforming manufacturing technology and the distribution of production capital. As the use of three-dimensional printers begins to extend into homes, schools, and factories, the industry is not well equipped to address the potential for deleterious environmental and health impacts. Proactive assessment tools are needed so that materials developers and designers, printer operators, and print end users can create and choose the most appropriate and safe materials and AM processes based on their use cases. Current life cycle assessments (LCAs) do not provide sufficient information to support materials decisions based on concerns about hazard exposure. To address this shortcoming, we developed a framework that complements LCA with hazard and green design metrics derived from analyzing human health and environmental impacts in the later stages of the AM life cycle. We then identified suitable existing methodologies for evaluation across these stages and synthesized the methodologies into higher-level metrics for comparative analysis of materials. To illustrate the benefits of this framework, we compared two common AM materials: Autodesk Standard Clear Prototyping Resin (PR48), an open-source formulation used in photopolymerization processing AM, and bio-polylactic acid, a ubiquitous, biosourced polymer used in an extrusion-based AM system called fused filament fabrication.