## 4 Discussions  
### Process Settings' Influence over 3D Printing Time  
The results in Table 3 show that there were no significant changes in the printing time when switching between the infill patterns. For instance, in the case of sample 7, horizontally oriented, the printing time for the triangular infill was 16 h 35 min at 60% density, whereas for the zig-zag pattern, it was 16 h 28 min, and for the line pattern, it was 16 h 45 min. While it is acknowledged that the infill pattern does affect mechanical properties such as the compression or tensile strength of 3D prints [25; 26], its influence on printing time remains minor, especially for the specific case of wrist-hand orthoses with thicknesses up to 4 mm. The data also prove that the printing time is quite large and justify the focus on finding solutions to reduce it. Additionally, the results from the Cura slicer indicated that decreasing the layer thickness from 0.2 mm to 0.1 mm (to improve surface quality) can result in a printing duration exceeding 24 h. Even if the 3 DP-WHOs are not typically employed for emergency scenarios, a nearly day-long printing time is still not practical for this application. Another interesting observation is that when using the Auto-orientation option in Cura (which operates by minimizing the print's overhangs, thereby reducing the necessity for support structures) the orientation that also optimized the printing time was correct just for sample 2, while the orientation recommended by Meshmixer proved to be correct only for sample 7. This indicates that these optimization tools for build orientation are not consistently producing the expected outcome of reducing printing time. The printing time for the flat orthoses was significantly less than the printing time of orthoses with similar designs but manufactured in the other orientations (for instance, samples 1 vs. 2, or samples 3 vs. 4, in Table 3). Furthermore, as demonstrated by [18], horizontally manufacturing ready-to-use orthotic shapes does indeed reduce printing time. However, this horizontal orientation negatively affects the surface quality by producing a staircase effect on curved surfaces, as can be seen in Figure 8a. Typically, this staircase effect can be mitigated by reducing the layer thickness to smaller values [27]. However, this solution proves inefficient when dealing with the complex shapes of customized wrist-hand orthoses. As an example, no obvious improvement could be noted in Figure 9b, while the orientation more than doubled the printing time. Another unexpected result was observed for samples 2 and 3, where the printing time at 100% infill density was less than that for 80% infill density. This can be attributed to the complexity of the orthosis shape and the specific paths calculated by the slicer, which are followed by the nozzle to build each layer. By adjusting the value of the Support Overhang Angle parameter, one can reduce the required support structure, saving time during manufacturing (Figure 10): 11 h 50 min for a 45\({}^{\circ}\) overhang angle, 10 h 25 min for a 60\({}^{\circ}\) overhang angle, and 6 h 32 min for an 80\({}^{\circ}\) overhang angle (at 60% infill density). In their study, [PERSON] et al. opted for an 80\({}^{\circ}\) overhang angle when creating a custom 3D-printed wrist-hand orthosis with a 4 mm thickness manufactured in a vertical orientation [17]. It is worth noting that no printing difficulties were reported, likely due to the fact that their design was more robust with fewer open pockets. Another approach to reducing 3D printing time involves decreasing the infill density, as previously mentioned. However, it is important to carefully analyze all such solutions, as they may lead to various defects, as illustrated in Figure 11, or as discussed in prior research where mechanical resistance to flexural fatigue was investigated [13].