## 4 Conclusions  
This paper assesses the effect of the feed speed, cutting speed, tool construction, and mean chip thickness on the cutting power and circular saw blade surface temperature during the spruce (_Picea excelsa_) cutting on an experimental single-shaft circular saw. The main goal of the research was to achieve sustainable (acceptable) woodworking with the lowest energy consumption. Emphasis was placed on performing experiments under cutting conditions that occur in the secondary wood processing industry, to better study the harsh cutting conditions. In addition, the surface temperature of the circular saw blades was measured, which is a significant factor influencing the dynamic behavior of the saw blade in the cutting process. The role of the mean chip thickness in the cutting process, which represents the combined effect of several cutting factors as a critical factor, was also investigated. Future research should focus on extending the experiment to a wood cutting process with a higher moisture content (raw wood). The influence of the feed speed on the cutting power was in accordance with the data reported in the literature by several authors. Based on the measurement results, the value of the cutting power decreased in the feed speed range of (14-21) m/min. In the feed speed range of (21-28) m/min, the value of the cutting power increased. These data show that the lowest value of the cutting power at the given cutting parameters was achieved at a feed speed of 21 m/min for all circular saw blade designs and cutting speeds. Regarding the role of the circular saw blade design, we can see that the lowest value of the cutting power at the given feed speed was shown by the circular saw blade CSB3. Compared to the classic (unmodified) circular saw blade (CSB1), it showed cutting power values that were 8% lower. The influence of the feed speed on the values of the circular saw blade surface temperature confirmed the dependences which are presented in scientific articles by several authors. As can be seen from the measurement results, the circular saw blade surface temperature increases the most at the edge of the circular saw blade depending on the feed speed. The maximum temperature difference for uncoated CSB1 and CSB2 circular saw blades is \(T=8.5\,^{\circ}\mathrm{C}\). The temperature difference of 3 \({}^{\circ}\mathrm{C}\) was in the middle of the radius of these circular saw blades and a difference of \({}^{\circ}\mathrm{C}\) was around the flanges. The temperature difference at the coated (modified) CSB3 circular saw blade is \(T=0.5\,^{\circ}\mathrm{C}\) at all three positions of the temperature sensor. The course of the surface temperature of the circular saw blades has an assumed exponential course from the edge to the area of the flanges. The individual circular saw blades differ from each other only in the size of the temperature drop. For the CSB1 circular saw blade, the temperature drop was \(\Delta T=18.9\,^{\circ}\mathrm{C}\); for the CSB3 circular saw blade, it was \(\Delta T=3.1\,^{\circ}\mathrm{C}\). This large difference in the temperature gradient of the two circular saw blades is probably the reason for the change in the dynamic behavior of CSB3 in the cutting process, which was finally reflected in its lowest values of cutting power. The influence of the size of the average chip thickness on the values of the cutting power and the surface temperature of the circular saw blades is evident from Figures 7 and 11. Withan increasing value of the mean chip thickness in the range of 0.063-0.098 mm, the cutting power in the cutting process decreases for all three saw blades. In contrast, in the range of the mean chip thickness of 0.098-0.131 mm, the cutting power in the cutting process increases for all three circular saw blades. Under the given cutting conditions, all three circular saw blades showed the lowest values of cutting power at a mean chip thickness value of 0.01 mm.