Emissions and Chemical Exposure Potentials from Stereolithography Vat Polymerization 3D Printing and Post-processing Units

Abstract

Particles and volatile organic compounds (VOCs) have been detected emitting from material extrusion 3D printing, which is widely used in nonindustrial environments. However, vat polymerization 3D printing that is also commonly used has yet to be well-characterized for its emissions. In this study, we measured particle and VOC emission rates from stereolithography (SLA) 3D printing during print and post-processing wash and cure processes individually using a standardized testing method for 3D printer emissions in an exposure chamber. We observed minimal particle emissions and identified 30 to over 100 individual VOCs emitted from each operating phase, some of which accumulated after the printing ended. The total VOC emissions from SLA processes were higher than typical levels from material extrusion 3D printing, and the emission rate could be over 4 mg/h. Major VOCs emitted were associated with the resin and chemicals used in print and post-processing procedures, which included esters, alcohols, aldehydes, ketones, aromatics, and hydrocarbons. Emissions from post-processing units were lower than those from printing but also included chemicals with health concerns. The emitted mixture of sensitizers, carcinogens, irritants, and flammable chemicals may present a hazard for indoor air quality and human health. The estimated personal exposure to total VOC and some specific VOCs of concern to human health, like formaldehyde and naphthalene, exceeded the recommended indoor levels (e.g., California Office of Environmental Health Hazard Assessment), potentially causing irritation and other health impacts for 3D printer users.