3D Printer Enclosure & Indoor Air Quality

Reports

Photo credit: aaron.huo

Excerpts from three comprehensive articles published in the last four years and one blog post are presented below.

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1. Characterizing 3D Printing Emissions and Controls in an Office Environment. August 16, 2018 blog post.

The field team evaluated particulate and volatile organic compounds (VOCs) emitted from simultaneous operation of up to 20 desktop 3D printers in a conference room. Emissions from individual 3D printers were also evaluated using a portable isolation chamber developed by NIOSH researchers. 

  • During 3D printing, respirable particulate concentrations were non-detectable (below 0.03 micrograms per cubic meter, µg/m3) and VOC concentrations were well below applicable occupational exposure limits (OELs). Particulate and VOC concentrations measured in the conference room during 3D printing with 20 printers were much lower than those measured in the test chamber. This was likely due to general dilution as a result of the conference room’s larger ventilated space compared to the enclosed test chamber. However, local exhaust ventilation could reduce or eliminate the concentrations of ultrafine particle emissions that were measured in the conference room.
  • Another key finding of our study was that True Orange PLA filament produced lower ultrafine particle emissions compared to published results from other emission tests in the scientific literature…. additional research should be conducted to identify other lower emitting filaments as an option to reduce ultrafine emissions in the workplace and to develop a system to categorize 3D printer emission rates.

2. Evaluation of 3-D Printer Emissions and Personal Exposures at a Manufacturing Workplace. Health Hazard Evaluation Report 2017-0059-3291. Published August 2017.

“We collected canister samples at both locations in the Print Room to identify and quantify individual organic chemicals.” Photo by NIOSH.
  • Acetaldehyde, acetone, ethanol, isopropyl alcohol, and toluene are known to be emitted during printing with PLA filaments [Stefaniak et al. 2017].
  • Though the canister method we used is not fully validated, the presence of diacetyl and 2,3-pentanedione are of interest as these chemicals are often used as ingredients in flavorings and are known respiratory hazards [NIOSH, 2016].
  • Diacetyl and 2,3-pentanedione are types of chemicals referred to as “carbonyl” compounds which is a family of compounds with similar chemical structures.
  • Based on our previous studies of 3-D printing, using experimental sampling methods, we determined that some chemicals emitted during printing can react with ozone in air to form carbonyl compounds [Stefaniak et al. 2017].
  • As such, it is likely that diacetyl and 2,3-pentanedione were not emitted by the printing process but were formed in air from the reaction of ozone and other organic chemicals.

3. Characterization of chemical contaminants generated by a desktop fused deposition modeling 3-dimensional Printer. Published July 2017.

A desktop fused deposition modeling (FDM) 3-dimensional (3-D) printer using acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA) filaments and two monochrome laser printers were evaluated in a 0.5 m3 chamber.

  • TVOC [total volatile organic compound] emission rates were significantly lower for the 3-D printer (49–3552 μg h−1) compared to the laser printers (5782–7735 μg h−1).
  • A total of 14 VOCs [volatile organic compounds] were identified during 3-D printing that were not present during laser printing.
  • 3-D printed objects continued to off-gas styrene, indicating potential for continued exposure after the print job is completed.
  • Carbonyl reaction products were likely formed from emissions of the 3-D printer, including 4-oxopentanal.
  • Ultrafine particles generated by the 3-D printer using ABS and a laser printer contained chromium.

4. Emission of particulate matter from a desktop three-dimensional (3D) printer. Published online May 19, 2016.

  • A test chamber was used to generate a real-world emission atmosphere for desktop 3D printers. The chamber system (Figure 1A) consisted of (1) a 500-L stainless-steel chamber to house up to 2 printers for uninterrupted operation; (2) a desktop 3D printer (Replicator 2x®, MakerBot Industries, Brooklyn, NY); and (3) real-time and time-integrated sampling and monitoring instrumentation.
  • Filament type significantly influenced emissions, with acrylonitrile butadiene styrene (ABS) emitting larger particles than polylactic acid (PLA), which may have been the result of agglomeration.
  • Geometric mean particle sizes and total particle (TP) number and mass emissions differed significantly among colors of a given filament type.
  • Use of a cover on the printer reduced TP emissions by a factor of 2.
  • Lung deposition calculations indicated a threefold higher PLA particle deposition in alveoli compared to ABS.
  • Desktop 3D printers emit high levels of UFP [ultrafine particles], which are released into indoor environments where adequate ventilation may not be present to control emissions.

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Photo credit: European space agency

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