Nanoparticle Exposure and Workplace Measurements During Processes Related to 3D Printing of a Metal Object

Abstract

Metal 3D printing has many potential uses within prototyping and manufacturing. Selective laser melting (SLM) is a process that uses metal powders in the micrometer range as printing material. The particle release from the entire SLM printing process is not well-studied. While the 3D printing itself often occurs in a sealed chamber, activities related to the process can potentially release harmful metal particles to the indoor working environment through resuspension of the printing powder or via incident nanoparticles generated during printing. The objective of this study was to improve the understanding of particle exposure in work processes associated with 3D printing and potential needs for interventions by a case study conducted in a 3D printing facility. In this setting, direct release and dispersion of particles throughout the workspace from processes related to metal 3D printing was investigated. The release from five activities were studied in detail. The activities included post-printing cleaning, object annealing, and preparation of new base substrate for the next printing was. Three of the five measured activities caused particles number concentrations in the working environment to increase above background levels which were found to be 8·102 cm−3. Concentrations during chamber emptying and the open powder removal system (PRS) cleaning processes increased to 104 and 5·103 cm−3, respectively, whereas grinding activity increased number concentrations to 2.5·105 cm−3. Size distributions showed that particles were mainly smaller than 200 nm. Respirable mass concentrations were 50.4 μg m−3, collected on filters. This was corroborated by respirable mass measured with a DustTrak of 58.4 μg m−3. Respirable mass concentrations were below the occupational exposure limits in Denmark for an 8 h time-weighted average.

Occupational Exposure to Ultrafine Particles in Metal Additive Manufacturing: A Qualitative and Quantitative Risk Assessment

“…Occupational incidental nanoparticles usually originated from industrial processes that require high temperature or massive energy [4], such as metal additive manufacturing, which uses, for example, electron beams and lasers as heat sources. Recent studies have been published on this topic, showing the importance of studying the occupational risk of exposure to UFPs in metal AM workstations [7][8][9]. Some metal-based nanoparticles can cause adverse effects at cellular and subcellular levels.…”

Material Flow Analysis and Occupational Exposure Assessment in Additive Manufacturing End-of-Life Material Management

“…The inhalation exposure potential for solid-based processes can occur when feedstock powders and filaments are used in an area with minimal ventilation . VOC concentrations of 0.02–0.13 mg/m 3 (C exposure,disposal ) have been reported from solid material processing . Therefore, EXP inhalation may range from 0.2 to 1.3 mg/day/operator for solid disposal.…”

Emissions from 3D Printers as Occupational Environmental Pollutants

“…In the Jensen et al study, the number of particles identified in the various phases of metal 3D printing (SLM -Selective laser melting) ranged from 5×10 3 to 2.5×10 5 particles/cm 3 . [46]. In another study the most popular filaments of 3D printers (ABS, PLA) were tested and the particles they issue.…”