## 3 Results and Discussions
### Dimensional Accuracy  
Width deviations (%), thickness deviations (%) and cross-sectional areas (mm\({}^{2}\)) were calculated for each color and position using experimental data. Subsequently, means and standard deviations were determined for all types of specimens (Tables 2-4). \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Color**} & \multirow{2}{*}{**Code**} & \multicolumn{3}{c}{**Width (mm)**} & \multicolumn{3}{c}{**Thickness (mm)**} & \multicolumn{3}{c}{**Cross-Section Area (mm\({}^{2}\))**} \\  & & **Mean** & **Dev. ** & **Std. Dev. **  
The influences of the two independent variables (filament color and specimen position on the table) on width deviation, thickness deviation and cross section area deviations were statistical analyzed using the Two Way ANOVA test, in the following situations: (a) three specimens printed simultaneously; (b) five specimens printed simultaneously; (c) specimens printed in the center of the build plate (specimens 1.1, 3.2 and 5.3). The Eta squared factor (\(\eta^{2}\)) was used to measure the effect size (the proportion of the variation of the dependent variable that is correlated with the independent variable). **Three specimens printed simultaneously**  
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) = 130.917, p01 = 0.000;
* the effect of the specimen position on its area F02(2,60) = 14.806, p02 = 0.000. The strongest effect on the specimen area is exerted by the color of the material (\(\eta^{2}\) = 89.1%), followed by the position of the specimen on the build plate (\(\eta^{2}\) = 38.2%). Pearson correlation coefficient analysis shows that there is no statistically significant correlation between width deviations and thickness deviations (\(p\) = 0.600). Considering that the overall dimensional accuracy is reflected best by the resulted deviations of the cross-section area, the statistical validated dependencies between the two independent variables (the filament color and the specimen position on the build plate) and the cross-section area are visualized in Figure 3. The best dimensional accuracy was obtained, for this printing scenario, by the grey specimens (32.067 mm\({}^{2}\) mean value of the cross-section area for the whole batch of specimens, representing 6.89% increase to the nominal value of 30 mm\({}^{2}\)) and the worst by the red ones (33.898 mm\({}^{2}\), representing an increase of 12.99%). The black and the natural filaments led to intermediate values (area increases of 7.51% and respectively 10.10%). Regarding the second independent variable, respectively the position of the specimen on the build plate, the largest differences between the cross-section areas of specimens of the same color, printed in positions 3.1, 3.2 and respectively 3.3, resulted in case of the red prints (2.30%), followed by the black (1.70%), the grey (1.56%) and the natural (0.31%) specimens. It should be noted that all these differences are very small. An increasing trend of the dimensional deviations for the specimens printed on the right side of the build plate (specimens 3.3) can be observed for this printing scenario and all filament colors. Figure 3: The variation of the cross-section area (mm\({}^{2}\)) for three specimens printed simultaneous. **Five specimens printed simultaneously**  
The results of simple main effects test showed that there was a statistically signif-icant difference in:  
- the effect of the filament color on the specimen area F01(3,100) = 43.250, p01 = 0.000;  
- the effect of the specimen position on its area F02(4,100) = 5.094, p02 = 0.001. The strongest effect on the specimen area is exerted by the color of the material (n\({}^{2}\) = 61.4%), followed by the position of the specimen on the build plate (n\({}^{2}\) = 20.3%). Pearson correlation coefficient analysis shows that there is no statistically significant correlation between width deviations and thickness deviations (p = 0.351).