## 3 Results and Discussion
### Comparisons of Experimental and Numerical Results  
Figure 24a and b represent the UTS comparisons between experimental, ROM, and MROM results for ABS samples and printed in the LBO and TBO, respectively. The details of these graphs along with the error percentages for ROM and MROM are also separately placed in Tables 7 and 8. As can be seen from Figure 24a, although the MROM is a perfect match with the experimental results, the results were not much affected by the ROM, and they could also show an acceptable range. However, in Figure 24b, the ROM did not show an acceptable fit with the experimental results while the MROM was a very close and perfect match for the UTS results for samples printed in the TBO. This first shows how sensitive the TBO is to the infill changes in the system and shows how effective the MROM was in the modelling results.  
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline \multicolumn{6}{l}{**Longitudinal Build Orientation**} \\ \hline Nozzle & UTS\({}_{\text{(mean)}}\) & UTS\({}_{\text{SQRT Error Mean}}\) & \(\Delta_{\text{(mean)}}\) & \(\Delta_{\text{SQRT Error Mean}}\) & E\({}_{\text{(mean)}}\) & E\({}_{\text{SQRT Error Mean}}\) \\ temperature & (MPa) & (MPa) & (\%) & (\%) & (MPa) & (MPa) \\
220 \({}^{\circ}\)C & 22.6 & 0.27 & 0.24 & 0.019 & 1881 & 70.42 \\
240 \({}^{\circ}\)C & 32.42 & 1.36 & 0.26 & 0.005 & 2012 & 43.01 \\
260 \({}^{\circ}\)C & 38.75 & 0.34 & 0.30 & 0.005 & 2331 & 13.50 \\
280 \({}^{\circ}\)C & 35.19 & 0.22 & 0.318 & 0.027 & 2113 & 90.92 \\ \hline \multicolumn{6}{l}{**Transverse Build Orientation**} \\ \hline Nozzle & UTS\({}_{\text{(mean)}}\) & UTS\({}_{\text{SQRT Error Mean}}\) & \(\Delta_{\text{(mean)}}\) & \(\Delta_{\text{(SQRT Error Mean)}}\) & E\({}_{\text{(mean)}}\) & E\({}_{\text{SQRT Error Mean}}\) \\ temperature & (MPa) & (MPa) & (\%) & (\%) & (MPa) & (MPa) \\
220 \({}^{\circ}\)C & 8.96 & 0.51 & 0.07 & 0.001 & 1793 & 74.95 \\
240 \({}^{\circ}\)C & 9.66 & 0.62 & 0.08 & 0.005 & 1988 & 13.59 \\
260 \({}^{\circ}\)C & 19.03 & 0.61 & 0.22 & 0.018 & 1788 & 51.02 \\
280 \({}^{\circ}\)C & 7.85 & 0.13 & 0.10 & 0.017 & 1626 & 35.21 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Temperature influences UTS, \(\Delta\), and E values for ABS samples printed in the LBO and TBO at different layer thicknesses for ABS polymer.  
Figure 23: Mechanical anisotropy (\(\Delta\) (ABS)) for parts printed with different nozzle temperatures for ABS samples.  
Figure 24: UTS comparison between experimental results with those from ROM and MROM at different infill percentages for ABS samples: (**a**) samples printed in the LBO, (**b**) samples printed in the TBO.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Infill (\%)**} & **Experimental UTS** & **Calculated UTS** & **Calculated UTS from** & **Error (\%) ROM** & **Error (\%) MROM** \\  & **(LBO)** & **from ROM (LBO)** & **MROM (LBO)** & **Error (\%) ROM** & **Error (\%) MROM** \\ \hline
40 & 21.4 & 19.0 & 21.4 & 11.3 & 0.12 \\
60 & 22.9 & 22.3 & 22.8 & 2.7 & 0.40 \\
80 & 23.3 & 25.0 & 23.2 & 7.1 & 0.40 \\
100 & 32.0 & 33.5 & 31.9 & 4.5 & 0.25 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Effects of the infill percentage on UTS values obtained from experiments, ROM, and MROM with relative error percentages for ABS samples printed in the LBO.