Evaluating Measuring Techniques for Occupational Exposure during Additive Manufacturing of Metals: A Pilot Study

Abstract

SummaryAdditive manufacturing that creates three-dimensional objects by adding layer upon layer of material is a new technique that has proven to be an excellent tool for the manufacturing of complex structures for a variety of industrial sectors. Today, knowledge regarding particle emissions and potential exposure-related health hazards for the operators is limited. The current study has focused on particle numbers, masses, sizes, and identities present in the air during additive manufacturing of metals. Measurements were performed during manufacturing with metal powder consisting essentially of chromium, nickel, and cobalt. Instruments used were Nanotracer (10 to 300 nanometers [nm]), Lighthouse (300 nm to 10 micrometers), and traditional filter-based particle mass estimation followed by inductively coupled plasma mass spectrometry. Results showed that there is a risk of particle exposure at certain operations and that particle sizes tended to be smaller in recycled metal powder compared to new. In summary, nanosized particles were present in the additive manufacturing environment and the operators were exposed specifically while handling the metal powder. For the workers' safety, improved powder handling systems and measurement techniques for nanosized particles will possibly have to be developed and then translated into work environment regulations. Until then, relevant protective equipment and regular metal analyses of urine is recommended.

Addressing Hazardous Implications of Additive Manufacturing: Complementing Life Cycle Assessment with a Framework for Evaluating Direct Human Health and Environmental Impacts

“…For example, recently, Kim and colleagues () found that FFF 3D printers, regardless of the material used, emitted nano‐size particles at high concentrations, several aldehydes (including carcinogenic formaldehyde), phthalates, and VoCs such as toluene and ethylbenzene. In another example, Graff and colleagues () recently determined that there was significant operator exposure to metal particles larger than 300 nanometers (>10 8 particles per cubic meter over 10‐second cycles) when handling metal powders for SLS printing. Whereas welding processes, laser printers, and toasters have been known to produce similar concentrations of particulates, the toxicological profile of nanoparticles produced from AM plastics by FFF as well as certain metals like cobalt for SLS could be more harmful (Oberdörster et al.…”

Charting the Environmental Dimensions of Additive Manufacturing and 3D Printing

“…Three articles in this Special Issue address these topics (Graff et al. ; Mendes et al. ; Azimi et al.…”

“…Three articles contained in this Special Issue focus on the hazards inherent to machine emissions and operator exposure. The paper by Graff and colleagues () experimentally investigates particle numbers, masses, sizes, and identities present in the air during the operation of metallic AM processes, indicating that nano‐sized particles are present in the process environment and that operators are exposed specifically while handling the metal powder. Mendes and colleagues () characterize emissions from a low‐end 3D printer based on the extrusion of polymers, showing that the process emits nanoparticles inside the chamber, and negligible emissions in room experiments, with emission rates depending strongly on extruder temperature.…”

“…The investigation of these phenomena, which may all pose potential health risks, will require tailored approaches due to the large number of AM processes, build parameters, and materials. Three articles in this Special Issue address these topics (Graff et al 2017;Mendes et al 2017;Azimi et al 2017).…”

3D Printing and Industrial Ecology

“…; Graff et al. ; Mendes et al. ) and unit energy consumption will contribute building blocks to future LCA and other systems‐oriented work that is typical of IE.…”