PSI - Issue 83

E.N.T. Isidro et al. / Procedia Structural Integrity 83 (2026) 171–178

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3. Results 3.1. Specific weight

The relative density was calculated as the ratio between the experimental density and the theoretical density of the 1.2709 steel. The average values obtained for each combination of processing parameters are summarized in Table 4Figure 4 and graphically presented in Figure 5.

Table 4. Relative density of printed specimens.

Sample Strategy

VED (J/mm 3 )

Relative density [%]

1 2 3 4 5 6 7 8 9

96.0 60.0 40.0 26.7 20.0 96.0 60.0 40.0 26.7 20.0

99.59 98.88 93.24 86.60 81.23 99.55 96.44 88.98 83.39 79.50

Chessboard

Stripes

10

70% 72% 74% 76% 78% 80% 82% 84% 86% 88% 90% 92% 94% 96% 98% 100%

Relative density in as-built condition

Relative density [%]

Chess Stripes Chess Stripes Chess Stripes Chess Stripes Chess Stripes 96 96 60 60 40 40 26.7 26.7 20 20

VED [J/mm³]

Figure 5. Effect of volumetric energy density on relative density.

The findings demonstrate a robust relationship between the varying levels of volume energy density (VED) and the relative density of the specimens throughout the manufacturing process. Employing higher VED settings of 96 and 60 J/mm³, the maximum relative density of 99.5% was attained using the chessboard scanning strategy. This outcome is likely due to the increased energy availability, which promotes enhanced powder melting and a reduction in internal porosity. Conversely, a decrease in energy density resulted in substantial reductions in relative density, specifically to 80.9% and 78.7% at the lowest tested level of 20 J/mm³ for the chessboard and stripes strategies, respectively. This reduction is associated with an increase in internal defects, particularly lack-of-fusion pores. In comparison, the chessboard strategy consistently yielded higher relative density values, implying improved thermal uniformity, which can be attributed to its alternating scan vector pattern. As energy density was reduced to 60 and 40 J/mm³, porosity became more pronounced, especially with the stripes technique. At critically low energy densities (26.7 and 20 J/mm³),