## 2 Materials and Methods  
The same cutting conditions were applied in related papers [1; 29]. Below, we provide some information about the experimental conditions. The material used to machine the samples was Inconel 625 alloy, which is a popular material in the aerospace industry in the nickel alloy group. Nickel alloys, like titanium alloys, find their use in aerospace structures such as engine components in particular, where resistance to high temperatures is required (in the range of 900-1300 \({}^{\circ}\)C) [14; 15]. Nickel alloys provide excellent heat-resistant properties, which means that they retain their strength, stiffness, dimensional stability, and ductility at much higher temperatures than common materials used in aerospace applications such as titanium alloys or aluminum alloys, and they are also characterized by high fatigue strength, resistance to stress cracking at high temperatures, and resistance to corrosion and oxidation [12]. The material properties and chemical composition of Inconel 625 nickel alloy are shown in Tables 1 and 2. Thin-walled components such as turbine blades, for example, are observed in aircraft engines. Nickel-based alloys are the most commonly used materials in turbine engines due to their high strength and long fatigue time with good resistance to oxidation and corrosion at high temperatures [12]. The percentage of nickel alloys in the construction of the entire aircraft is small compared to other alloys used in their construction, but they are, nevertheless, the subject of research by scientists [30; 31; 32; 33] due to the use of these materials in severe operating conditions [16]. A series of six nickel alloy specimens (Figure 1) were machined (milling) at a constant cutting speed of V\({}_{\text{c}}\) = 40 m/min and feed rate of V\({}_{\text{f}}\) = 255 mm/min using different machining strategies on a Mikron VCE 600 P-type numerical machine tool. During machining, SILUB MAX coolant was used--a water-oil emulsion with a mixture of 15% oil emulsion and 85% water [34]. Three \(\varnothing\)10 mm diameter monolithic cutters were used in the milling process: JS554-100E2R050.0Z4-SIRA (the tool for general purpose--dedicated to machining all materials), JS754100E2C.0Z4A-HXT (the tool for high-performance machining--dedicated to machining titanium alloys and nickel superalloys), and JH730100D2R100.0Z7-HXT (the tool for high-speed machining--dedicated to machining titanium alloys and nickel superalloys) [35; 36; 37]. We adopted two different approaches for adaptive milling--face and cylindrical. During adaptive face milling, we assumed a depth of cut of 2.00 mm and a radial depth of 4.00 mm (Figure 2a). For adaptive cylindrical milling, we assumed a depth of cut of 6.00 mm and a radial depth of 1.33 mm (Figure 2b). Based on the feed rate, depth of cut, and depth of cut presented, one can see that the value of material removal rate MRR is constant and equal to 2.03 cm\({}^{3}\)/min. Table 3 shows the combination of cutting tools and cutting strategies used for the Inconel 625 nickel alloy samples marked N1-N6. \begin{table}
\begin{tabular}{c c c} \hline
**Mechanical Properties** & **Value** & **Unit** \\ \hline Tensile strength R\({}_{\text{m}}\) & min. 760 & MPa \\ Yield strength 0.2\% & min. 380 & MPa \\ Elongation at break & min. 35 & \% \\ Density & 8.44 & g/cm\({}^{3}\) \\ \hline \end{tabular}
\end{table} 
Table 1: The mechanical properties of Inconel 625 [22]. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline
**Element** & **Ni** & **Cr** & **Mo** & **Nb** & **Fe** & **C** & **Mn** & **Si** & **S** & **Al** & **Ti** & **P** & **Co** \\ \hline Percentage (\%) & \(\geq\)58 & 20–23 & 8–10 & 3.15–4.15 & \(\leq\)5 & \(\leq\)0.1 & \(\leq\)0.5 & \(\leq\)0.5 & \(\leq\)0.015 & \(\leq\)4.4 & \(\leq\)0.4 & \(\leq\)0.015 & \(\leq\)1 \\ \hline \end{tabular}
\end{table} 
Table 2: The chemical composition of Inconel 625 [22]. Figure 1: Manufacturing documentation of a sample with a thin wall in horizontal orientation [1; 29].