3D Printing Emissions Research Accepted for Publication
The first major publication of the joint UL/Georgia Tech research team on 3D printing research has been accepted for publication in the July issue of the Aerosol Science and Technology journal. It can be found at http://www.tandfonline.com/doi/full/10.1080/02786826.2017.1342029.
In addition, the Standard Consensus Group has been formed and the ANSI standard for 3D Printing and Emissions will begin in July.
Particle emissions from multiple fused deposition modeling consumer 3D printers were systematically quantified utilizing an established emission testing protocol (Blue Angel) to allow quantitative exposure assessments for printers operating in different environments. The data are consistent with particle generation from volatilization of the polymer filament as it is heated by the extruder. Typically, as printing begins, a burst of new particle formation leads to the smallest sizes and maximum number concentrations produced throughout the print job.
For acrylonitrile butadiene styrene (ABS) filaments, instantaneous concentrations were up to 106 #/cm3 with mean particle sizes of 20 to 40 nm when measured in a well mixed 1 m3 chamber with 1 air change per hour.
Particles are continuously formed during printing and the size distribution evolves consistent with vapor condensation and particle coagulation. Particles emitted per mass of filament consumed (particle yield) varied widely due to factors including printer brand, and type and brand of filament. Higher extruder temperatures result in larger emissions.
For filament materials tested, average particle number yields ranged from 7.3 x 108 to 5.2 x 1010 g-1 (approximately 0.65 to 24 ppm), with trace additives apparently driving the large variations. Nanoparticles (diameters less than 100 nm) dominate number distributions, whereas diameters in the range of 200 to 500 nm contribute most to estimated mass.
Because 3D printers are often used in public spaces and personal residences, the general public and particularly susceptible populations, such as children, can be exposed to high concentrations of non-engineered nanoparticles of potential toxicity.
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