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TECHNOLOGY 37
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performance and material consumption. the interaction between the two factors was not statistically
Configuration 3P20 exhibited the highest mean specific significant (p = 0.826).
bending moment, followed by configuration 3P30, whereas These results indicate that the material efficiency of the
further increases in perimeter count or infill density did not joints was influenced by both the thickness of the outer shell
improve material efficiency. and the amount of material used in the infill.
For maximum bending moment, the analysis showed a Although increasing infill density resulted in higher filament

significant effect of perimeter count on joint maximum bending consumption, it was not accompanied by a proportional
moment (p < 0.001). increase in maximum bending moment, leading to a reduction
In contrast, infill density did not significantly affect maximum in specific bending moment.
bending moment (p = 0.402), and no significant interaction The highest mean specific bending moment was obtained
between perimeter count and infill density was detected (p for configuration 3P20 (3,903 ± 104 N·mm/g), whereas the
= 0.153). lowest value was recorded for configuration 5P40 (2,608 ±
These results indicate that joint maximum bending moment 380 N·mm/g).
is governed primarily by the thickness of the outer shell formed Among all configurations, 3P20 achieved the best material
by the perimeter walls, whereas increasing infill density within efficiency, while 3P30 provided the highest overall mechanical

the investigated range (20–40 percent) does not provide a performance (maximum bending moment and rotational
significant improvement in strength. stiffness) with moderate material consumption.
Load transfer is therefore carried mainly by the outer Configurations with 5 perimeters or 40 percent infill density
material layers, which resist the normal and shear stresses consumed more material and printing time without proportional
developed in the most highly loaded regions of the connector. mechanical benefits.
For rotational stiffness, neither of the investigated factors FEM analysis was used to support the experimental
showed a statistically significant effect. Perimeter count did results and explain the load-transfer mechanism between the

not significantly affect joint stiffness (p = 0.090), nor did infill FDM-printed connector and the wooden slot. The contact
density (p = 0.145). The interaction between both factors was outputs were evaluated for connector configurations with
also not significant (p = 0.121). three perimeter walls (3P).
Although some differences were observed among the This group was selected because the experimental and
tested configurations, the overall stiffness remained at a statistical results indicated that the 3P configurations provided
comparable level. a favourable balance between mechanical performance and
These findings indicate that variations in perimeter count and material consumption among the evaluated configurations.
infill density within the investigated range did not substantially Compared with 1P configurations, 3P connectors provided
influence the rotational stiffness of the joints.

This conclusion is consistent with previous studies, which
reported that perimeter and infill parameters influence the David Baillot
mechanical response of FDM-printed parts, while their effect
depends on the specific performance criterion considered.
The two-way ANOVA for specific bending moment
revealed statistically significant effects of both perimeter
count (p < 0.001) and infill density (p < 0.001). In contrast,