Exploring Methods for Surveillance of Occupational Exposure from Additive Manufacturing in Four Different Industrial Facilities

Abstract

3D printing, a type of additive manufacturing (AM), is a rapidly expanding field. Some adverse health effects have been associated with exposure to printing emissions, which makes occupational exposure studies important. There is a lack of exposure studies, particularly from printing methods other than material extrusion (ME). The presented study aimed to evaluate measurement methods for exposure assessment in AM environments and to measure exposure and emissions from four different printing methods [powder bed fusion (PBF), material extrusion (ME), material jetting (MJ), and vat photopolymerization] in industry. Structured exposure diaries and volatile organic compound (VOC) sensors were used over a 5-day working week. Personal and stationary VOC samples and real-time particle measurements were taken for 1 day per facility. Personal inhalable and respirable dust samples were taken during PBF and MJ AM. The use of structured exposure diaries in combination with measurement data revealed that comparatively little time is spent on actual printing and the main exposure comes from post-processing tasks. VOC and particle instruments that log for a longer period are a useful tool as they facilitate the identification of work tasks with high emissions, highlight the importance of ventilation and give a more gathered view of variations in exposure. No alarming levels of VOCs or dust were detected during print nor post-processing in these facilities as adequate preventive measures were installed. As there are a few studies reporting negative health effects, it is still important to keep the exposure as low as reasonable.

Keywords: 3D printing; VOC; additive manufacturing; diary; exposure; industry; material extrusion; material jetting; occupational; particles; powder bed fusion; vat photopolymerization.

Figure 1.

Concentrations of particles sized 0.1–10 µm measured by the DataRAM™ pDR1000AN at facility A-PBF. The figure has been labelled to illustrate what tasks were carried out during the measurement time. Identification of tasks is a combination of observations during the measurements and information from the exposure diary. In this figure, cleaning denotes cleaning of the printing and post-processing rooms with a vacuum cleaner and not cleaning of the printer. Other 3D reflects dyeing printed object (first mention) and refilling powder container (second two instances).

Figure 2.

Emissions of particles sized 10 nm to 1 µm during various AM tasks at A-PBF, measured by CPC 3007. The instrument was held as closely as possible to the operator during task measurements and placed roughly in the middle of the room during stationary measurements.

Figure 3.

A clear pattern in signal from VOC sensor at MJ is likely due to changes in ventilation settings. White field is the time between 06:00 and 19:00, dark grey field is when additional measurements were performed.

Figure 4.

Data from VOC sensor mounted close to the printers and operators computer station. The shaded area represents the day where other measurements also were carried out.