3.1.2. SEM and EDS

The data collection included two samples of stainless steel 316L: One of the raw powder before printing and other of the powder after the laser action, which is collected after printing to be reused in future prints. Scanning electron microscopy and energydispersive X-ray spectroscopy analysis were performed to these two samples, to study possible changes in size, shape and/or chemical composition. The results are shown in Figures 3–6.

**Figure 4.** EDS analysis results: Stainless steel 316L raw powder, before any AM process.

**Figure 5.** SEM analysis results: Stainless steel 316L powder after AM process. (**a**) Size and shape of particles in the sample; (**b**) image of the particle analyzed by EDS (results in Figure 6).

To better characterize the size and shape of the particles released to the work atmosphere during this AM process, the air samples collected on the polycarbonate membrane filter and on the heat-treated quartz filter were subjected to SEM. EDS analysis was also carried out to verify the elementary composition of these samples. Figures 7–10 illustrate these results.

**Figure 6.** EDS analysis results: Stainless steel 316L powder after printing.

**Figure 7.** SEM analysis results: airborne sample collected on quartz filter. (**a**) Size and shape of particles in the sample; (**b**) image of the particle analyzed by EDS (results in Figure 8).

**Figure 8.** EDS analysis results: Airborne sample collected on quartz filter.

**Figure 9.** SEM analysis results: airborne sample collected on polycarbonate filter. (**a**) Size and shape of particles in the sample; (**b**) image of the particle analyzed by EDS (results in Figure 10).

**Figure 10.** EDS analysis results: Airborne sample collected on polycarbonate filter.
