## 3 Results and Discussion  
To conduct the investigations, 2 \(\times\) 3 sets of tools (1 set = 9 pieces) were printed, resulting in a total of 2 \(\times\) 27 cutting edges. Three sets were designed for cutting 0.22 mm thick Al99.5 H24 sheets and three for 0.3 mm thick sheets. Each tool performed six cuts, and after every three cuts, the tools were scanned (as outlined in the process diagram) to determine the extent of tool wear. The total number of cuts needed to carry out the experiment was, therefore, 54 \(\times\) 6, or 324. As anticipated, some tools failed under the applied load, sometimes breaking during the very first cut. One such failed tool is shown in Figure 9.  
The experimental results demonstrated that most tools performed well; however, certain cutting edges experienced significant deformation or fracture during the cutting process. This issue was particularly evident in tools A1 and B1, which were printed with a 2 mm wall thickness and oriented at 0\({}^{\circ}\) or 15\({}^{\circ}\). Burr formation was also examined visually during the tests. The degree of burr formation was categorized as minimal when barely noticeable by touch, with a burr thickness of 0.01-0.05 mm; as moderate when clearly noticeable by touch but not necessarily requiring post-processing, with a burr thickness of 0.05-0.1 mm; and as severe when the burrs were sharp, easily visible, and potentially hazardous, exceeding a thickness of 0.1 mm. In many cases, the cut workpieces exhibited high-quality contours. Burr formation was either absent or minimal for several tools. In some instances, however, minimal to moderate burr formation was observed, likely influenced by human factors during the pressing process. Minor positional variations in the tool system during each pressing cycle, as well as slight shifts in the relative positions of the sheet, rubber pads, and pressing element, may have contributed to this outcome. For tools manufactured using FDM technology with PLA material, seven out of nine tool designs successfully completed all six cuts on 0.22 mm thick Al99.5 sheets. Exceptions included models A1 and A2, which displayed significant deformation and cracking after the third cut, rendering them unsuitable for further operations. Figure 10 compares the cutting edges of models A1 and A2 after three cuts with their initial state. Figure 9: Deformed cutting edges. During the evaluation, the initial and post-sixth pressing states were compared using GOM software. After aligning the models, color maps generated by the software highlighted differences between them. By placing measurement points on the models, these deviations could also be quantified numerically. For the seven cutting edges that successfully completed all six cuts, the average edge wear was in the range of hundredths of a millimeter, with values ranging from -0.05 mm to +0.04 mm. These measurements align with the IT9-IT10 tolerance class (ISO 286-1) [51], which is considered acceptable for this technology. Among the seven models, almost all performed well, but the A3 and C3 models stood out, with average deviations not exceeding 0.04 mm. Detailed evaluation results for the C3 model are shown in Figure 11.  
Beyond the color-mapped tool analysis, the cut workpieces were also examined, focusing primarily on burr formation. For the well-performing tools, minimal burr formation was observed in every case. An example of a successful cut using a 0.22 mm thick sheet is shown in Figure 12.  
Figure 11: Edge wear values for model C3—0.22 mm thick Al99.5 sheets. Figure 10: Edge wear values for models: (**a**) A1 and (**b**) A2—0.22 mm thick Al99.5 sheets. Evaluation of the 0.3 mm thick Al99.5 sheets was carried out similarly to the thinner sheets. However, cutting the thicker 0.3 mm sheets proved less successful. Tools A1, A2, B1, and C1 were unable to complete all six cuts, as they suffered significant deformation during the process and were unsuitable for further use.