AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Aerosol Emission from Low-cost Metal and Thermoplastic 3-D Fabrication
JUN WANG, Kevin O'Neill, Jose Muniz, Joshua Pearce, David L. Johnson, University of Oklahoma
Abstract Number: 64 Working Group: Aerosol Exposure
Abstract Three-dimensional (3-D) fabrication is a process that involving the users to access instruments such as 3-D printers, cutters, and engravers. Most of the equipment relies on pyroprocessing to melt and remold the consumables or filaments to a pre-designed shape. A previous study on a low-cost single-nozzle thermoplastic 3-D printer with various filaments indicated that the high-temperature process raised concerns of potential carcinogenic aerosol emission and exposure. The lowered cost of 3-D fabrication devices brought more applications to places where sufficient ventilation and engineering control were often lacking to mitigate the aerosol emission. The objective of this study was to characterize aerosol emission from a series of low-cost 3-D fabrication equipment, namely a dual-nozzle thermoplastic 3-D printer, a mild and stainless steel metal 3-D printer, and a 3-D laser engraver and cutter. The equipment were placed in enclosed chambers and fume generated were measured with various particle sizers and indoor air quality sensors. A scanning mobility particle sizer and aerodynamic particle sizer were employed to examine the particle size distribution in the fine (<0.5 µm) and coarse ranges (<0.5~20 µm), while a GRIMM aerosol spectrometer was used to determine the respirable, thoracic, and inhalable fraction of the aerosol. Particle morphology was recorded via a transmission electron microscope (TEM). The results showed a high emission (~108 to 1010 #/minute of printing time) of particles with mode size in the ultrafine range. The ultrafine aerosols were also visually confirmed in the TEM images. The metallic aerosol compositions from metal 3-D fabrication were similar to the metal filaments. Particulate Cr6+ concentration in the chamber without ventilation is several folds higher than the permissible exposure limit. The findings suggested that cautious should be taken to avoid overexposure to ultrafine particles while dealing with low-cost metal and thermoplastic 3-D fabrication.