## 4 Conclusions  
The goal of our research was to find the optimal combination of parameters of the cutting process with a beam of a CO\({}_{2}\) laser energy of a 8 mm thick spruce board with a moisture content of 12% and thus to achieve the required quality of cutting. The targets of past research were mainly equivalent homogeneous wood material. The target of this research was highly anisotropic material. Therefore, \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multirow{2}{*}{**Goal**} & \multicolumn{2}{c}{**Cutting Kerf Width (mm)**} & \multicolumn{2}{c}{**Cutting Kerf Width (mm)**} & \multirow{2}{*}{**Improvement (\%)**} \\  & & **Reference** & & **Optimal** & \\ \hline WKU* & min & 0.715 & 0.627 & 12.3 \\ WKD* & min & 0.591 & 0.416 & 29.6 \\ WKR* & 1 & 0.528 & 0.670 & 21.1 \\ WHAZU* & min & 0.786 & 0.764 & 2.7 \\ WHAZD* & min & 0.808 & 0.679 & 16 \\ B* & min & 0.117 & 0.144 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 6: A table presenting the parameters at 150 W power (reference) and 100 W power (optimal), for a cutting speed of 9 mm-s\({}^{-1}\) and AR = 3. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Goal** & \multicolumn{2}{c}{**Cutting Kerf Width (mm)**} & \multirow{2}{*}{**Suitability**} & \multirow{2}{*}{**AR**} & \multirow{2}{*}{**P (W)**} & \multirow{2}{*}{**V (mm-s-1)**} \\  & & & **(mm)** & & & & \\ \hline WKU* & min & 0.627 (0.565) & 0.92 & 3 & 100 & 9 \\ WKD* & min & 0.327 (0.334) & 0.92 & 11 & 100 & 9 \\ WKR* & 1 & 0.853 (0.853) & 0.92 & 3 & 150 & 3 \\ WHAZU* & min & 0.663 (0.113) & 0.92 & 3 & 100 & 3 \\ WHAZD* & min & 0.679 (0.093) & 0.88 & 3 & 100 & 9 \\ B* (B) & min & 0.117 (33.245) & 0.69 & 3 & 150 & 9 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Results of separate optimization of the investigated factor settings. parameter AR was considered and discussed, in addition to standard parameters, such as the effect of the cutting speed V and beam power output P, and the influence of these parameters on responses was also analyzed too, including the cutting kerf width on the upper board's surface WKU, cutting kerf width on the board bottom WKD, the width of the heat-affected area on the upper board's surface WHAZU and the board bottom WHAZD, the ratio of the cutting kerf width on the board bottom to the width on the upper board's surface WKR, and the degree of char B. Using a mathematical-statistical model, we achieved the optimal parameters (AR = 3, 100 W, and 9 mm\(\cdot\)s\({}^{-1}\)). These parameters of cutting are much better than the non-optimized control parameters (AR = 3, 150 W, and 9 mm\(\cdot\)s\({}^{-1}\)). The improvement in the quality ranged from 3% to more than 30%. The results exhibit a high correlation with experimental measurements and they are also comparable to the results of research on the cutting of more homogeneous wood and wood composite materials cut with a CO\({}_{2}\) laser. Research has further shown that even inhomogeneous materials such as spruce wood can be cut with a low power laser. However, in order to make this process more predictable, further research should focus on assessing the impact of other factors, such as the spruce moisture content and composition and flow rate of the auxiliary gas, and extending the ranges of factors considered, especially the beam power output and the cutting speed. We can use the method of measuring the cutting kerf width in other areas, where we require a fast and inexpensive method to measure small lengths, which are determined by the resolution of the scanning device. At the same time, this method is suitable for the proposal of electronic equipment that would perform the measurements of small two-dimensional objects. The used method of char measuring can be applied in the mass identification of errors or characteristic properties of the surface of the scanned workpiece by division into characteristic areas.