The Influence of Polylactic Acid Filament Moisture Content on Dust Emissions in 3D Printing Process

Abstract

This paper presents the results of a study on the effect of moisture content in polylactic acid (PLA) filaments on dust emissions during incremental manufacturing. The tests were conducted in a customised chamber using a standard 3D printer, and Plantower PMS3003 sensors were used to monitor air quality by measuring PM1, PM2.5 and PM10 concentrations. The filament humidity levels tested were 0.18%, 0.61% and 0.83%. The results show that a higher moisture content in the filament significantly increases dust emissions. For dry filaments (0.18% humidity), the average dust emissions ranged from 159 to 378 µg/m³. Slightly humid filaments (0.61%) produced higher emissions, with averages between 59 and 905 µg/m³, with one outlier reaching up to 1610 µg/m³. For very humid filaments (0.83%), the highest average emissions were observed, ranging from 57 to 325 µg/m³, along with greater variability (standard deviation up to 198). These findings highlight that increased filament humidity correlates with elevated dust emissions and greater instability in emission levels, raising potential health concerns during 3D printing.

Keywords: PLA; additive manufacturing; dust emissions; filament moisture; laser dust sensors.

Figure 1

Schematic of the test bench.

Figure 2

Measuring module with DHT22 sensor [48].

Figure 3

Measuring device.

Figure 4

Dependence of dust concentration increase on process duration for sensor 1 for dry filaments.

Figure 5

Dependence of dust concentration increase on process duration for sensor 1 when the filaments were soaked for three hours.

Figure 6

Dependence of dust concentration increase on process duration for sensor 1 when the filaments were soaked for twelve hours.

Figure 7

Dependence of dust concentration increase on process duration for sensor 1 for a printing temperature of 185 °C.

Figure 8

Dependence of dust concentration increase on process duration for sensor 1 for a printing temperature of 200 °C.

Figure 9

Dependence of dust concentration increase on process duration for sensor 1 for a printing temperature of 215 °C.

Figure 10

Dependence of dust concentration increase on process duration for different particle sizes for a printing temperature of 200 °C with dry filaments.

Figure 11

Dependence of dust concentration increase on process duration for different particle sizes for a printing temperature of 200 °C with filaments soaked in distilled water for three hours.

Figure 12

Dependence of dust concentration increase on process duration for different particle sizes for a printing temperature of 200 °C with filaments soaked in distilled water for twelve hours.