## 3 Results and Discussions
### Dimensional Accuracy
The best dimensional accuracy, as shown by Figure 4, was obtained by the grey specimens (32.372 mm\({}^{2}\) mean value of the cross-section area for the whole batch of specimens, representing 7.91% increase to the nominal value of 30 mm\({}^{2}\)) and the worst by the red ones (34.027 mm\({}^{2}\), representing an increase of 13.42%). The natural and the black filaments led to intermediate values (increase of 10.66%, respectively 11.43%). On the other hand, if considering the second independent variable, respectively the position of the specimen on the build plate, shown by the statistical analyze of the experimental results to influence less than the filament color, the largest differences between the cross-section areas of specimens of the same color, printed in positions 5.1, 5.2, 5.3, 5.4 and respectively 5.5, resulted in case of the black prints (3.65%), followed by the red (2.23%), the grey (2.11%) and the natural (1.82%) specimens. Also in this case, these differences are small. At the same time, one can observe again increased cross-section deviations for the specimens positioned on the right side of the build plate (specimens 5.4 and 5.5), that have to be caused by the non-uniform temperature distribution inside the printing chamber. The measurements made for the specimens printed with natural PLA are the only ones that do not confirm this trend. This might be explained by different thermal properties of the material. **Specimens printed in the central position (1.1, 3.2 and 5.3)**  
In order to point out the influence of the number of simultaneous printed specimens on their dimensional accuracy, a comparative analysis of the cross-section area deviations of the specimens printed in the center of the build plate when applying the three printing scenarios was realized (specimens 1.1, 3.2, and 5.3). Figure 4: The variation of the cross-section area (mm\({}^{2}\)) for five specimens printed simultaneous. Two-way ANOVA results showed that there was a statistically significant interaction between the effects of the filament color and the printing scenario on the specimen cross-section area F03(6,60) = 3.002, p03 = 0.014. The results of simple main effects test showed that there was a statistically significant difference in:  
* the effect of the filament color on the specimen area F01(3,60) = 41.677, p01 = 0.000;
* the effect of the printing scenario on the specimen area F02(2,60) = 7.676, p02 = 0.001. The strongest effect on the specimen cross-section area variations is exerted by the material color (n\({}^{2}\) = 72.3%), followed by the color-printing scenario interaction (n\({}^{2}\) = 27.3%) and the printing scenario (n\({}^{2}\) = 24.2%). After validation by two-way ANOVA of the dependencies between independent and dependent variables, the experimental results could be considered for interpretation. The comparative analysis of the specimens printed in the center of the build plate regarding the deviations of the cross-section area, visualized in Figure 5, shows a low increase of the dimensional deviations between individually printed specimens and five specimens printed simultaneously. In numerical values, considering the increase of the cross-section area in relation to its nominal value (30 mm\({}^{2}\)), the strongest effect was recorded in case of the black prints (33.440 mm\({}^{2}\), representing an increase of 3.96%) and the weakest for the grey prints (32.243 mm\({}^{2}\), representing an increase of 0.46%). The influence of the printing scenario on the area of the natural and the red specimens was recorded to be situated between the two values mentioned before (increase of 1.07%, respectively 0.92%). The results obtained for three specimens printed simultaneous showed very small differences in relation to individually printing (increase of the cross-section area situated between 0.08% for black PLA and 1.38% for natural PLA, respectively area reduction of \(-\)0.42% in case of grey PLA) and no evident tendency regarding the variations could be pointed out.