## 3 Results and Discussions
### Systematic Distribution of Measurement Points  
In contrast to the randomly selected points, this study used specific measurement points of the examined surface. The assumption was to achieve the same number of point sets as with the random method. A selection of evenly distributed points from a matrix  
Figure 9: Summary of the results of the obtained flatness error and time for three devices for randomly selected points [own elaboration]. containing data on all 189 points collected during the study was used. The obtained results are presented in the summary below--Figure 10.  
Figure 10 confirms the results presented in Figure 9. Preparing an automatic machine takes more time; however, the results obtained with its help have the smallest flatness error. We can start the results fastest on a manual machine, but with a large number of points, the total measurement time for the measuring arm will be less. The measuring arm requires more time to prepare before starting measurements, but the measurement is shorter, so with a large number of collected points, the measurement will take less time. The flatness error range of the results obtained for both devices is at a similar level; however, the average value of the flatness error for the arm is greater. Plane measurement accuracy--the central point of our article is the analysis of the accuracy of plane flatness measurements made using different methods: CNC machine, manual machine and measuring arm. This study sheds light on the unique properties of the CNC machine, which is characterized by the smallest flatness error with a value of (f) = 61.9 \(\upmu\)m, emphasizing its superiority in terms of accuracy over other methods. The inaccuracies of the machine readings along with their resolution are in Table 3. Each machine has the same elementary unit, which is 1 \(\upmu\)m (micrometer). Measurement repeatability--the second key area of our interest is the analysis of the repeatability of results obtained using the above-mentioned techniques. We have shown that the CNC machine shows the highest repeatability, which is important when taking into account the efficiency of measurements in various production and repair scenarios. Repair and production application--the focus is also on the discussion of the practical application of different measurement methods in the context of individual, small-scale  
Figure 10: Summary of flatness error results and time for three devices for systematically selected points [own elaboration]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Measurement Method**} & \multicolumn{3}{c}{**Measurement**} & \multicolumn{3}{c}{**Measurement Variability**} & \multirow{2}{*}{**Average**} \\  & **1** & **2** & **3** & **4** & \(\Delta\)f = fmax — fmin & \\ \hline Semi Automatic & 83.0 & 64.4 & 63.2 & 70.7 & 19.8 & 70.3 \\ Machine & 79.7 & 80.0 & 90.7 & 84.5 & 11.0 & 83.7 \\ Automatic Machine & 61.9 & 59.6 & 58.7 & 59.6 & 3.2 & 59.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Summary of flatness measurement results [own research]. production and repair work of large power machines. We indicate how the choice of measurement method affects the efficiency and time consumption of the process, as well as the possible benefits of measurement automation. Tables 4 and 5 present both the advantages (e.g., the possibility of replacing precise devices under certain conditions) and limitations (e.g., low repeatability of results in the case of a measuring arm for a small number of points) of the tested methods, with reference to our own concept presented in this article.