## 3 Results and Discussion  
Figure 4 illustrates the force-displacement curves of the compact specimens tested for each of the printing orientation angles under consideration. Figure 4: Load–displacement curves from compact tension tests conducted for each printing orientation. Source: own elaboration based on calculation results with Spyder (v. 5.5.1). Figure 3: Blade with 0.5 mm Radius Used for Machining the Notch Tip According to ASTM D5045-99 Guidelines. Photo credit: authors. The results of this graphic allow for the calculation of several key parameters, including the initial stiffness and maximum load of the curves. The initial stiffness, calculated as the slope of the initial linear portion of the curve, indicates the resistance of the material to elastic deformation. The maximum load represents the maximum force sustained by the material before failure. Table 1 presents a summary of the initial stiffness and maximum load of the force-displacement curves for different print orientations. The aforementioned values correspond to the mean values of the three samples tested for each case. The results indicate relatively consistent stiffness across the different orientations, suggesting a similar performance in terms of material resistance to deformation. The peak load values exhibit moderate variability, indicating that the material can sustain a relatively consistent maximum force. Notably, while there is a reduction in both stiffness and peak load as the pressure plane changes, this difference is approximately 10%, consistent with the results presented in [29]. The observed variability of approximately 10% in the mechanical properties can be attributed to certain factors associated with the manufacturing process of the specimen. In particular, the curing process may exert an influence on the ultimate characteristics of the printed specimens. The generation of the notch using the blade during the tests represents another factor that could potentially influence the results. This dispersion is consistent with the findings reported by other authors in the literature [29], indicating that such variability is not uncommon in similar studies. Furthermore, it is crucial to emphasize that these tolerances are deemed acceptable, particularly in biomechanical applications, where minor discrepancies are unlikely to significantly impact the overall performance and functionality of the materials in question. The value of the structural toughness of the material can be determined based on previous records, using the following expression [31]. \[K_{Q}=\frac{P_{Q}}{BW^{\frac{1}{2}}}\;\;f(x) \tag{1}\]  
If the function \(f\) (\(x\)) is calculated as follows, where \(x=\text{a}/W\):  
\[f(x)=6x^{1/2}\frac{1.99-x(1-x)\big{(}2.15-3.93x+2.70x^{2}\big{)}}{(1+2x)(1-x)^ {3/2}} \tag{2}\]  
To calculate \(P_{Q}\) according to the specified standard, first determine the initial compliance C by loading the specimen and drawing a best-fit straight line (AB) on the load-displacement curve. The compliance C is the reciprocal of the slope of this line. Then, draw a second line (AB8) with compliance 5% greater than that of line AB. If the maximum load _Pmax_ sustained by the specimen falls between lines AB and AB8, use \(P_{max}\) to calculate \(K_{Q}\). If _Pmax_ falls outside this range, determine \(P_{Q}\) as the intersection of line AB8 with the load curve. It is important to ensure that the condition \(P_{max}/P_{Q}<1.1\) is met to validate the test. Table 2 presents the values of \(P_{Q}\) for each of the samples tested, along with the mean values and standard deviation. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Specimens** & **0\({}^{\circ}\)** & **45\({}^{\circ}\)** & **90\({}^{\circ}\)** \\ \hline Stiffness [N/mm] & 129.68 & 117.90 & 111.67 \\ Peak load [N] & 316.01 & 296.13 & 285.50 \\ \hline \hline \end{tabular} \({}^{1}\) Depending on the orientation of each print on the selected specimens. Source: own elaboration based on calculation results with Spyder (v. 5.5.1).  
\end{table}