# The Influence of Automated Machining Strategy on Geometric Deviations of Machined Surfaces
## 4 Evaluations of Geometrical Characteristics
between flatness and vertical planes is shown in Figure 6. Flatness measurement tolerances were measured at a speed of 8 mm/s along a defined path (polyline), and a spline filter with wavelength Lc = 2.5 mm was used (roughness Ra = 0.4-3.2 \(\mu\)m). In two cases, flatness was better for the CAM system SolidCAM and in one case for Heidenhain TNC 426. After all flatness deviations were compared, globally smaller deviations for Heidenhain TNC 426 were found in four cases and for system SolidCAM in three cases. In the case of the evaluation of perpendicularity, it was necessary to define the reference plane to which the given tolerance would be evaluated. Table 4 describes the evaluated geometric tolerances and reference planes for the perpendicularity of the planes. All perpendicularity tolerances were measured at a speed of 8 mm/s along a defined path (polyline) and a spline filter with wavelength \(Lc\) = 2.5 mm. The evaluation of the perpendicularity of the planes showed that the plane PER_A_per had the lowest perpendicular deviation, and planes B1_short a B2_short had the highest. Three deviations of four SolidCAM systems had a smaller deviation. The difference between systems SolidCAM and Heidenhain TNC 426 was less than 0.01 mm (Figure 7). \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Evaluated Plane** & **Reference Plane** \\ \hline PER\_A\_per & A-PER & Plane\_A \\ PER\_Plane\_B1\_PER\_long\_pd\_PER & B1-PER\_long & Plane\_A \\ PER\_B1\_short\_pd\_B1 & B1\_short & Plane\_B1 \\ PER\_B1\_short\_pd\_B2 & B2\_short & Plane\_B2 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Evaluated geometric tolerances and reference planes for the perpendicularity of the planes. Figure 6: Deviation for flatness—vertical. The perpendicularity of cylinders was evaluated in two methods: as the perpendicularity of the cylinder to the primary reference plane Plane_A in parallel direction to the secondary reference plane A-PER and as the perpendicularity of the cylinder to the primary reference plane Plane_A in the perpendicular direction to the secondary reference plane A-PER. In three cases, the deviation (Figure 8) was smaller for the SolidCAM system, although only minimally (maximum difference was 0.0038 mm). The parameters of plane parallelism evaluations are shown in Table 5. The parallelism was measured at a speed of 8 mm/s along a defined path (polyline), and a spline filter with wavelength \(Lc\) = 2.5 mm (roughness Ra = 0.4-3.2 mm) was used. The parallelism deviation of the two horizontal planes (PAR_C_pd_A) showed a significantly higher value than area B2_long to area B1_long. The plane PAR_C_pd_A was measured by the polyline path. The main difference was in the form of a deviation of parallelism. The SolidCAM system showed larger differences than the Heidenhain system. The parallelism of PAR_B1_per-long was measured using 4 lines. The parallelism of each line from plane B2_long to plane B1_long was evaluated. In two cases, the SolidCAM system had a smaller deviation (Figure 9), and in two cases, it was Heidenhain TNC 426. The maximum difference was less than 0.0072 mm. When comparing the two systems on the PAR_C_pd_A plane, no significant difference in parallel deviations or in their distribution was visible (Figure 10). With the CAM system SOLIDCAM, where the tool overlap was 50%, a more pronounced tool path on the surface could be seen than in the Heidenhain system, where the tool overlap was 70%. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Evaluated Plane** & **Reference Plane** \\ \hline PAR\_C\_pd\_A & Plane\_C & Plane\_A \\ PAR\_B1\_per-long\_1 & B2-PER\_long & B1-PER\_long \\ PAR\_B1\_per-long\_2 & B2-PER\_long & B1-PER\_long \\ PAR\_B1\_per-long\_3 & B2-PER\_long & B1-PER\_long \\ PAR\_B1\_per-long\_4 & B2-PER\_long & B1-PER\_long \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Parameters of planes parallelism evaluations. Figure 8: Deviations for perpendicularity—cylinders.