Safety in Additive Manufacturing: particulate exposure. Focus on NOAA

Additive manufacturing (AM) is a manufacturing process that was developed in the 1980s and is now mature enough to be used profitably and functionally. Since 2012, this has resulted in exponential growth in the AF sector in Europe, with no less than seven different families of technologies grouped together under the name "additive manufacturing" or "3D printing". The associated risks depend on the technology and products used. Due to the micron characteristics of the powders used and their use in the various AF technologies, exposure to inhalable and respirable dust (or particulate exposure) is one of the main risks to be considered. Technological development must be accompanied by rigorous risk assessment and the implementation of appropriate preventive measures.

However, in addition to the "classic" problem of particulate exposure, which is directly linked to the nature of the powders used, the metal FA sector has to contend with potential exposure to nano-objects, their aggregates and agglomerates (NOAA). This nanometric fraction is a by-product of laser-induced powder melting, and at the end of the process is suspended in the manufacturing machine, mixed with unused powder and on printed parts. The presence of this NOAA fraction is already widely referenced for polymer 3D printers.

Currently, there is no consensus on the hazardousness of NOAA, but given the nature of the powders used (particulate exposure assessment) and the 2018 IARC (International Agency for Research on Cancer) report on welding fumes, the precautionary principle applies to limit worker exposure.

Based on this observation, work has been initiated on the subject of particulate emissions, including NOAA, in metal FA by applying and adapting methodologies for measuring worker exposure in the workplace when handling nanomaterials. The aim is to gain a better understanding of potential NOAA emissions during various process operations, so as to include them as early as possible in associated risk analyses.