As 3D printing technologies becoming popular and available to the general public, concerns have been raised on the emissions and potential health impacts of operating 3D printers in indoor environments. This research involved a comprehensive study of the particle emissions from consumer level 3D printers. Particle emissions were characterized using a standard test method developed for laser printers in an environmental chamber. The factors affecting particle emissions, such as printer brand, print filament material, brand and color, extrusion and build plate temperature, were systematically investigated. Acrylonitrile butadiene styrene (ABS) material, emitted orders of magnitude more particles than polylactic acid (PLA) in general. To understand the particle formation mechanism, an aerosol dynamic model was used to simulate the steady state particle characteristics during printing. This model linked the observed particle concentration distributions to the model parameters of precursor gas properties, and explained the contrasts among the most important controlling factors. Finally, multiple approaches were applied to assess particle toxicity. A consistency among various methods showed that PLA emitted particles induced similar levels of responses at much lower doses than particles generated from ABS filaments. However, calculations for the overall exposure showed ABS filaments may be more harmful due to their much higher emissions. Overall, 3D printers are sources of high levels of ultrafine particles, which are potentially harmful for their users, suggesting that methods to mitigate emissions should be considered and exposures minimized.
Thesis Advisor: Dr. Rodney J. Weber (EAS), Academic Advisor: Dr. Armistead G. Russell
Dr. James A. Mulholland, Dr. Joe Brown, and Dr. Marilyn S. Black (Underwriters Laboratories Inc.)