Ultrafine aerosol transient phase measurement with real-time monitoring instrument applied to cleaning process of L-Pbf machine

Object This research addresses different issues related to the ventilation and the aerosol concentration present in a metal additive manufacturing facility using Laser Powder Bed Fusion (L-PBF) machine. Performing air monitoring requires quantifying the emissions potentially generated in the different areas and during the different L-PBF process phases. A practical Indoor Air Quality (IAQ) assessment protocol is addressed in this research questioning the type of emissions to measure, and the way to collect them. Methods As a measurement strategy for the airborne particles lower than 700 nm, real-time metrology discmini instruments were used (Testo, 1 L.min(-1), Forbach, France). The particle number concentration was assessed during three operations: (i) before cleaning the room where the L-PBF machine is located, (ii) during the cleaning phase of the room, and (iii) after the cleaning phase. Results Without ventilation and without human activity, the background concentration level in the additive manufacturing facility was 5.10(3) #/cm(3) either before or after cleaning. With ventilation and without human activity, the background concentration level was decreased to 4.10(3) #/cm(3) before cleaning, and increased to 1.5.10(4) #/cm(3) after cleaning. Besides, human activity leads to an increase in the number of suspended particles, since they passed from 5.10(3) #/cm(3) to 1.9.10(4) #/cm(3). Finally, a value of 10(5) #/cm(3) was recorded on the operator during the cleaning phase and clearly, show peaks of particle number concentration. Conclusion It was found that the local ventilation plays a role in the resuspension of particles from surfaces. Indeed, particles deposited on the floor are a source of exposure and hence the need for a clean room. The result section reinforces the necessity of wearing individual protective equipment during the maintenance and cleaning operations of a facility including L-PBF machine.

Automated summary

This research investigates ventilation and aerosol concentration in a metal additive manufacturing facility using L-PBF machine. Real-time metrology instruments were used to assess particle number concentration, revealing the impact of ventilation and human activity on particle levels. The study highlights the importance of individual protective equipment during maintenance and cleaning operations.