## 4 Discussion  
When comparing the tensile strength results from [PERSON] et al. [14] with the obtained mean strength results in this test, the values are equal. However, when choosing the parameters with a hatch distance of 0.295 mm and orientation of 45\({}^{\circ}\) in the upper level and a hatch distance of 0.266 mm and orientation of 55\({}^{\circ}\) in the lower level, tensile strength values of 43 N/mm\({}^{2}\) are achieved, which is a 37% higher value. Working with different orientations, [PERSON] et al. [13] managed to obtain a maximum tensile strength of 33 N/mm\({}^{2}\), which correlates with the mean value in both levels in this experiment, certainly less than the maximum value of 47 N/mm\({}^{2}\). [PERSON] et al. determined that altering only the orientation of the product (along the \(x\)-\(y\)-\(z\) axis) within the working chamber resulted in measured values displaying predominantly positive deviations in length along the \(x\) axis. Conversely, deviations measured along the \(y\) axis were predominantly negative. The smallest length deviations occurred when the product was rotated successively by 90\({}^{\circ}\), 90\({}^{\circ}\), and 0\({}^{\circ}\), followed by 0\({}^{\circ}\), 90\({}^{\circ}\), and 90\({}^{\circ}\), and, finally, 90\({}^{\circ}\), 90\({}^{\circ}\), and 90\({}^{\circ}\) along the \(x\), \(y\), and \(z\) axes, respectively [20]. To compare these results with those obtained in this experiment, it can be concluded that the orientation in the \(z\) axis must be 45\({}^{\circ}\) for the upper level in the working chamber and 55\({}^{\circ}\) for the lower level to achieve minimal dimensional deviations, which the authors in paper [20] established for the orientation in the \(z\) axis exclusively 0\({}^{\circ}\) and/or 90\({}^{\circ}\). However, the achievement of minimal dimensional deviations also depends on the other processing parameters, which [PERSON] et al. did not include in their experiment. [PERSON] et al. analyzed the influence of laser power, hatch distance, and energy density on mechanical properties and concluded that with a hatch distance of 0.16 mm, a tensile strength of 42 N/mm\({}^{2}\) is achieved [21]. Upon comparison with the proposed test, this value is achieved at a hatch distance of 0.29 mm, regardless of whether it is situated at the upper or lower level of the chamber. The study by [PERSON] et al. [22] merits attention as it aligns with a comparable approach to this work. However, in [PERSON] et al. 's study, they evaluated flexural and shear properties using original and recycled materials across two levels, with the upper level positioned at a height of 50 mm. The results of the tests conducted showed that the products with the best flexural properties are those made in the central zone of the working chamber, and the dimensions show that there is no difference between those built on the upper and lower parts of the working chamber, which is comparable to the analyses conducted in this experiment. [PERSON] et al. also stated that only thickness shows the  
Figure 13: Desirability curve for the solution of the lower part of the working chamber according to Table 21.  
lowest deviations along the \(z\) axis. This stands in contrast to the tests conducted in this paper, as the analysis revealed no difference in dimensional stability between the initial level of 6 mm and the subsequent level of 174 mm. However, in the mentioned work, the authors utilized only one orientation of the test specimens along the \(x\)-\(y\) axes (0\({}^{\circ}\)). The influence of orientation on the mechanical properties of PA12 in the SLS process was published in the paper [23] authored by [PERSON] et al. Through the comparison of four different orientations, they concluded that the best mechanical properties are exhibited by the edge 0\({}^{\circ}\) orientation in the horizontal plane XX axis.