## 3 Results and Discussion
### Experimental Results  
As described previously, this study investigates the effect of scanning strategies on the D-PBSLP of SiC and shows the best scanning strategy to be used. Four SiC samples (10 \(\times\) 10 \(\times\) 8 mm\({}^{3}\)) were printed using the parameters obtained from the numerical model (100 mm/s scanning speed, 32 W laser power, 35 \(\upmu\)m hatching distance, 22 \(\upmu\)m layer thickness, and with different scanning strategies such as linear, zigzag, concentric in-out,  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sintering Speed, mm/s** & **Laser Power, Wa** & **Sintering Contour** & **Sintering Path Width, \(\upmu\)m** \\ \hline
500 & 60 W & & \\
250 & 45 W & & \\
100 & 32 W & & \\
and hexagonal), as can be seen in Figure 10. The samples were successfully printed using the parameters obtained from the numerical model, and this proved the capability of the numerical model to predict the suitable process parameters even for materials that are difficult to print using a D-PBSLP technique, such as SiC. It is worth mentioning that there is a breakage at the corner of the sample printed using linear strategy, and this happened during the removal from the base plate as the samples were strongly attached to the baseplate. To evaluate the effect of scanning strategies on the D-PBSLP of SiC, all samples' relative densities were measured, and the results are summarized in Figure 11. Almost all scanning strategies gave a close relative density value. Both linear and concentric strategies obtained good relative density values of 76.6% and 79.9%, respectively. Zigzag and hexagonal strategies obtained the highest relative densities of 81.6% and 82.5%, respectively. Optical microscopic analysis was used to check the top surface of the samples, as shown in Figure 12. A flat surface without any characteristic pattern was achieved using zigzag and linear strategies. For the concentric in-out strategy, a characteristic pattern has appeared on the sample's top surface. This pattern is in two intersecting lines, which made an \"X\" shape on the layer's top surface. The developed numerical model was used to  
Figure 11: Relative densities for SiC samples printed with different scanning strategies. Figure 10: SiC samples printed using the process parameters obtained from the numerical model with different scanning strategies. simulate two connected paths in this scanning strategy, and it was found that when the laser changed its direction, a sharp increase in temperature occurred, as can be seen in Figure 13. This sharp increase in temperature is high enough to decompose the material at the point of rotation. There are four points per cycle, and therefore, the X shapes were formed at the end of scanning. To avoid this pattern, a modification required for this scanning strategy. The hexagonal strategy also showed a characteristic pattern on the sample's top surface where the hexagon shapes can be seen. It can be concluded that these characteristic patterns that occurred in both concentric and hexagonal strategies make them ineffective for the D-PBSLP of SiC. Based on the measured relative density and the layer's top surface pattern, the zigzag strategy can be considered the best strategy for PBSLP of SiC. SEM images (Figure 14) were used to check the morphology for hexagonal, zigzag, and concentric in-out strategies on the sample's top surface. The sintered surface was observed in hexagonal and zigzag strategies without any characteristic pattern. The level of porosity can be clearly seen where it is high in the case of the concentric strategy and low for both the hexagonal and zigzag strategies. Additionally, in the concentric in-out strategy, laser tracks are apparent on the layer's top surface and the laser rotation positions. No cracks can be seen in any strategy. The linear sample was not checked using SEM due to the low relative density as the vacuum process required to start the SEM analysis failed many times.