PSI - Issue 77

V. Kroužecký et al. / Procedia Structural Integrity 77 (2026) 161 – 169 Vít Kroužecký / Structural Integrity Procedia 00 (2026) 000 – 000

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confirm that although lower inclination angles are associated with increased surface roughness, the observed dependence on VED remains consistent across all investigated geometries.

Figure 3 Effect of volumetric energy density on down surface quality at different inclination angles

For the subsequent mechanical testing, an inclination angle of 30° was selected. This choice was motivated by the fact that components relevant to the targeted applications in the energy industry are typically characterized by overhang geometries close to this inclination. To ensure a meaningful comparison, the five best-performing parameter sets identified from the down surface roughness experiments were selected and compared against the machine manufacturer’s default process parameters. An overview of the selected parameter sets in relation to the default settings is provided in Table 4 Process parameters

Table 4 Process parameters

Parameters of laser Laser Power Scan speed Hatch distance Layer thickness Printing angle

Default parameters

Improve parameters

74 W

200

951 [mm/s] 0,1[mm]

951 [mm/s] 0,08[mm]

40 [µm]

40 [µm]

30°

30°

Figure 4 Layout of mechanical test specimens

When comparing the surface roughness of samples produced with standard process parameters and with a set of modified parameters, no significant differences in absolute roughness values were observed. The key distinction, however, lies in the surface topology. Samples fabricated using the modified parameters exhibit a considerably more consistent and homogeneous surface structure compared to those produced with the standard parameters, which may directly influence the subsequent mechanical behaviour of the material. These results are summarized in Table 5 Surface roughness of testing sample , and a visualization of the surface topology of both samples is presented in Figure 5 Surface topology, modify parameters (top image) default parameters (bottom image)