Multiple studies indicate that workers are being exposed to emissions from material extrusion three-dimensional (3D) printing processes and suffering adverse health effects from the exposures. To mitigate these exposures, we developed and evaluated four low-cost engineering controls to capture particle emissions during 3D printing processes. Two controls (Controls A and B) were custom developed using 3D printed parts and retrofitted onto the extruder of two open-frame desktop fused filament fabrication (FFF) 3D printers (Printers 1 and 2) to capture emissions near the source. A third control (Control C) used a commercially available, printer-specific enclosure that partially encapsulated Printer 2, while a fourth control (Control D) was built using acrylic panels to fully enclose Printer 2. Particle emissions from each control were exhausted through NIOSH-designed air filtration units consisting of a high-efficiency filter, blower fan, and 3D printed housing/components. Control effectiveness was evaluated in an emissions test chamber by comparing average particle concentrations at the chamber outlet while 3D-printing a National Institute of Standards and Technology (NIST) test artifact with black acrylonitrile butadiene styrene filament, with and without the controls in operation. Minimum capture efficiencies were 99.7% for Control A, 91.6% for Control B, 28.6% for Control C, and 99.8% for Control D. Internal cooling fans in Printer 2 allowed particle emissions to bypass Control C, limiting its effectiveness. Overall, capturing emissions at the source (Controls A and B) and full enclosure (Control D) were highly effective and demonstrated that low-cost engineering controls can mitigate particle emissions from 3D printing processes. • Low-cost controls can reduce emissions from desktop 3D printers • Custom 3D-printed nozzles reduced particle emissions by over 90% • Enclosing printers with HEPA filtration reduced emissions by 99.8% • Poorly designed enclosures allowed particles to bypass the filter • Emission capture at the source is critical for effective control
O’Connor et al. (Sun,) studied this question.