Sampling and characterization of particle emission from the 3D FDM printing

Fused deposition modeling (FDM) printers dominate the consumer market because of their low cost and high efficiency, resulting in an annual market growth rate of 40%. However, undesired emission of nanoparticles during the printing is accompanied, which can cause adverse health effects. It is very desirable to quantify these nanoparticles. However, the size and concentration (or size distribution) of these nanoparticles change dynamically due to ongoing nucleation, condensation and coagulation and these mechanisms are sensitively affected by printing and environmental conditions. An accurate size distribution of the emitted nanoparticles can only be obtained by a rigorous experimental design. This study designed a sampler to reduce the influences from sampling and environmental conditions and to help accurately characterize the instantaneous emitted nanoparticles. Using the sampler, the emissions from six different filaments, including an original poly-lactic acid (PLA-O), a carbon-fiber-filled PLA (PLA-C), an iron-additive PLA (PLA-Fe), an original white acrylonitrile butadiene styrene (ABS-W), a florescent ABS (ABS-F) and a glow-in-dark ABS (ABS-G) filament were characterized and compared. The results showed that the sampler method detected the particle emissions earlier than traditional methods, which had a majority size less than 20 nm. The ABS-W had the highest emission rate of 4.3 x 10(10) #/g which was about one order of magnitude higher than that of ABS-F, ABS-G and PLA-Fe (~10(9) #/g) and three orders of magnitude higher than PLA-O and PLA-C filaments (~ 10(7) #/g). A new metric, dynamic emission index (DEI), was proposed to characterize the dynamic changes of emitted nanoparticles during the printing. With the DEI, one can clearly identify the emission intensity for different sizes of particles along the printing time for different filaments and take required precautions if needed.