## 3 Results and Discussion  
### Results of Optical Measurements  
An example of the color maps obtained for sample N1 using the optical method is shown in Appendix A in Figure 11. Figures 6 and 7 show plots of the dimensional variation for specimens made of nickel alloy with horizontal thin walls, measured in a direction parallel to the direction of tool feed movement. The plots of the dimensional variations for the nickel alloy specimens in the direction parallel to the feed direction of the milling cutter are similar. There is a symmetrical relationship between the dimensional deviations of the machined surface and the dimensional deviations occurring from the bottom of the specimen concerning the horizontal axis of the coordinate system y = 0 (N1-N6, excluding N5). A symmetrical relationship can be seen between the graphs for the same cross-sectional plane. The thin wall thickness for the specimens is close to 1.00 mm (positive value). An exception to this rule is observed for sample N5 (the tool for high-performance machining, adaptive cylindrical milling), where negative dimensional deviations are observed for the samples. Hence, material losses result. The curves are shifted towards the horizontal axis y = 0 by about 0.10 mm; hence, the resulting wall thickness is approximately 0.90 mm. The largest variation is seen in the middle of the sample length, i.e., in the central part between the mounting points. Figure 5: Measurements by the contact method: (**a**) 1—sample, 2—probe, 3—posts; (**b**) basing method [1]. Figure 6: _Cont._Figure 6: Dimensional variation of the horizontal thin wall in the direction parallel to the direction of tool feed motion, for samples made of nickel alloy machined using an adaptive face milling strategy—determined by the optical method: (**a**) N1; (**b**) N2; (**c**) N3. Figure 7: _Cont._  
The similarity of the curve shapes is not as pronounced as in the case of titanium alloy samples [1]. Two groups of curves of a similar nature are evident. In the first group, we have samples N1, N2, and N5; in the second group are samples N3, N4, and N6. Figures 8 and 9 show the dimensional variations for nickel alloy specimens with thin horizontal walls, measured in the direction perpendicular to the direction of feed movement, determined by the optical method. The results for samples with thin horizontal wall of nickel alloy in the direction perpendicular to the direction of the milling cutter's feed motion (Figures 8 and 9) confirm the relationship observed when analyzing the results in the parallel direction, manifested by an approximately symmetrical distribution of the graphs with respect to the horizontal axis (y = 0) for specimens N1-N4 and N6. The symmetric distribution occurs between planes occurring in the same section. The N5 sample shows a shift of the curves toward negative values. The results for nickel alloy samples (Figures 7 and 8) show smaller values when using adaptive cylindrical milling (N4-N6) than those obtained with the adaptive face milling strategy (N1-N3). Although the use of adaptive cylindrical milling (N4-N6) gives more favorable results, a decrease in deviations on the planes of the machined surface can be observed from a length of about 20 mm. This seems related to the shining of the sample [1]. The largest limit of variation is seen for specimen N6, made with the tool for high-speed machining. The decrease in variation is approximately 0.1 mm. For specimens machined with the adaptive face milling strategy (N1-N3), this change is not so visible in our graphs (Figure 8). Figure 8: _Cont._  
Figure 7: Dimensional variation of the horizontal thin wall in the direction parallel to the direction of tool feed motion, for samples made of nickel alloy machined using an adaptive cylindrical milling strategy—determined by the optical method: (**a**) N4; (**b**) N5; (**c**) N6. Focusing on the individual samples, we can see that a scatter of values characterizes the N1 sample and is similar to both samples made with the tool for high-performance machining (N2 and N5).