Ultrafine Particle and Volatile Organic Compound Emissions from a 3D Printer Filament Extruder Slides

Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF) 3D printers have been shown in numerous studies to emit incidental ultrafine (1-100 nm) particles and volatile organic compounds (VOCs) from the use of plastic filaments. Filament extruders have recently entered the consumer market, designed for at-home hobbyists to create feedstocks for 3D printers from raw plastic pellets as an alternative to buying plastic filaments. Given the similarity in processes and materials used by 3D printers and filament extruders, we hypothesized that filament extruders may also release ultrafine particle emissions and VOCs. In this study, emissions from a consumer filament extruder were investigated for the first time. An off-the-shelf filament extruder was operated in a 2 m3 chamber using three separate feedstocks: acrylonitrile butadiene styrene (ABS) pellets, pulverized poly-lactic acid (PLA), and PLA pellets. Ultrafine particle emissions were measured in real-time using a scanning mobility particle sizer while non-targeted and targeted analysis of VOCs in emissions were captured using thermal desorption tubes. The number and mass concentration of ultrafine particles were comparable to those found in 3D printer studies, with the greatest to least concentrations from ABS pellets, pulverized PLA, and PLA pellets, respectively. In addition, the majority of particles released were found to be ultrafine, similar to 3D printer studies. A variety of VOCs, including styrene and ethylbenzene, were identified using the ABS and PLA feedstocks. The average mass concentration of styrene were found to be near the EPA Integrated Risk Information System (IRIS) Reference Concentration for Inhalation Exposure for 3- and 5-minute samples. The results indicate that the use of a filament extruder may present an additional exposure risk to 3D printer hobbyists. Further studies will be needed to determine the impact on emissions of environmental volume, air exchange rate, extruder settings such as extrusion speed and the use of nanomaterials in the filament creation process.

Impact/Purpose

Fused Deposition Modeling (FDM) 3D printers have been shown to produce emissions that consist of both particles and volatile organic compounds (VOCs) that are released from the heated feedstock material as it is pushed through the printer's nozzle to create a 3D object. The majority of these particles have been consistently found to be ultrafine in size (less than 100 nm in physical diameter) and released on the order of millions to billions of particles per minute. Emitted VOCs that have been recorded include styrene, ethylbenzene and benzaldehyde. To reduce the filament cost, 3D printer filament extruders are being used in residential and small business settings to create filaments for 3D printers and customized compositions. Creation of filament using raw plastic pellets can be cheaper than buying fabricated filament and give the consumer the option of recycling used plastic. To our knowledge, emissions from at-home filament extruders have not been previously reported. Given the similarity in processes and materials used by 3D printers and filament extruders, we hypothesized that filament extruders may also release ultrafine particle emissions and VOCs. An off-the-shelf filament extruder was operated in a 2 m3 chamber using three separate feedstocks: acrylonitrile butadiene styrene (ABS) pellets, pulverized poly-lactic acid (PLA), and PLA pellets. Ultrafine particle emissions were measured in real-time using a scanning mobility particle sizer and thermal desorption tubes were used for both non-targeted and targeted analysis of VOCs present in emissions. Ultrafine particle number and mass concentrations were comparable to those found in 3D printer studies with the greatest to least concentrations from ABS pellets, pulverized PLA, and PLA pellets, respectively. In addition, the majority of particles released were found to be ultrafine (1-100 nm), similar to 3D printer studies. A variety of VOCs were identified using the ABS feedstock, including styrene and ethylbenzene, and PLA feedstock. Exposure to particles and VOCs from the use of these devices may pose a risk to users particularly in confined spaces. Given the increasing use of these processes, program or regional partners, general public, and local communities will likely find this study of interest.

Citation

Byrley, P., A. Wallace, W. Boyes, AND K. Rogers. Ultrafine Particle and Volatile Organic Compound Emissions from a 3D Printer Filament Extruder Slides. American Chemical Society Fall 2020 Meeting, NA, CA, August 17 - 20, 2020.