## 3 Results and Discussion
### Wear and Tool Life Analysis  
The average value of the measured base indicator of a new saw \(\overline{W}_{z0}\) was 0.09 mm. This indicator was used to calculate the actual wear of a given tooth \(Z_{i}\) according to Equation (1). The average wear values of 40 teeth of individual circular saw blades (\(\overline{Z}_{i}\) indicator) are presented in Table 3. The same table also shows the total cutting length realized by the circular saw blade. We can see that, in pairs (non-treated and ion-implanted tools), they overcame the same total cutting length. It was consistent with the methodology of industrial research, where two circular saw blades were operated simultaneously on one machine, and their replacement took place on the same total cutting length, based on the poor quality of the machining edges observed by the machine operator, regardless of whether it was for a non-treated tool or for an ion-implanted tool. Table 3 shows that in two cases, the wear of the ion-implanted circular saw blades is lower than that of the non-treated circular saw blades on the same total cutting length, \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Implanted** & **Peak Volume Dopant Concentration** & **Projected Range** & **Range Straggling** & & **Sputtering Yield** \\
**Surface** & \(N_{max}\) & \(R_{p}\) & \(\Delta R_{p}\) & **Skewness** & **Kurtosis** & **Y** \\  & (cm\({}^{-3}\)) & (nm) & (nm) & (nm) & & **(Atoms/Ion)** \\ \hline W-C-Co & \(5.17\times 10^{22}\) & 31.6 & 37.8 & 0.8574 & 3.6237 & 0.49 \\  & (4.89 \(\times 10^{22}\)) & (31.8) & (32.4) & (0.2732) & (2.5179) & (0.48) \\ W-C & (4.98 \(\times 10^{22}\)) & 31.3 & 37.4 & 0.8597 & 3.6271 & 0.48 \\  & (4.93 \(\times 10^{22}\)) & (31.4) & (32) & (0.2936) & (2.5403) & (0.47) \\ Co & \(4.75\times 10^{22}\) & 38.1 & 44.8 & 0.826 & 3.4617 & 0.92 \\  & (4.63 \(\times 10^{22}\)) & (38.4) & (36.8) & (0.1878) & (2.5197) & (0.87) \\ \hline \end{tabular} The data for ACS cases are in the round brackets.  
\end{table} 
Table 2: Values of the parameters of nitrogen peak and the sputtering yield. Figure 9: Modelled nitrogen depth profiles in WC-Co.  
while in one case the tools were worn evenly. Be aware that tool wear is not yet tool life. To obtain the tool's life, it was necessary to use the linear function of the estimated linear least squares method (Equation (2)) and calculate the tool life for the adopted blunting criterion (tool life criterion) equal to 0.5 mm. The estimated total cutting length obtained in this way, corresponding to the tool life, is shown in Figure 10.  
Figure 10 also shows the value of the relative tool life index calculated according to Equation (3). More than a three times greater estimated lifetime of nitrogen-implanted tools was achieved in relation to non-treated tools. It may be surprising that such a large difference between the estimated tool life is not visible in the measured wear of individual groups of tools. It should be remembered that the increase in wear in the second wear phase (steady-state wear region) on the classic wear curve (Lorenz wear curve--Figure 7) is very slight (slight slope of the linear function), hence even a small difference in the tool wear may result in large disproportions in tool life, and so it was in this case. The above considerations are valid only for comparable cutting regimes because no information about the results obtained in more \"aggressive\" cutting regimes have been achieved at this moment. It remains to be decided what causes the lower wear and the increased life of nitrogen ion-implanted tools. Earlier studies indicated a large role of carbon in the shaping of tool life. It was shown that for the W/C ratio below the value of 0.9, the highest cutting length of tools was obtained after nitrogen ion implantation with the energy of 50 keV [1], more than twice as long as the non-treated tools. Other anti-wear mechanisms that occurred after nitrogen ion implantation were also indicated. Another one is the deformation of the crystal lattice of the implanted material.