## 6 Conclusions  
Since the required product quality affected CNC parameters of the machine tools, the CNC parameters must be selected to vary the machining performance of the tool-path planning, named as \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Description** & **HS** & **HP** & **HQ** \\ \hline Cycle time & 0\% & 37\% & 6\% \\ Dynamic errors & 66\% & 0\% & 16\% \\ Tracking error & 85\% & 28\% & 0\% \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of three machining modes from the experimental results. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**No.** & **Sym.** & **Description** & **Unit** & **HS** & **HP** & **HQ** \\ \hline N100 & \(J_{p}\) & Maximum jerk for tool-path movement & m/s\({}^{3}\) & 114.88 & 18.29 & 42.44 \\ N200 & \(A_{p}\) & Maximum acceleration for tool-path movement & m/s\({}^{2}\) & 3.02 & 0.48 & 1.12 \\ N300 & \(T_{p}\) & Time constant of Acc/Dec for tool-path movement & ms & 26 & 26 & 26 \\ N400 & \(T_{a}\) & Smoothing time constant for tool-path movement & ms & 1 & 1 & 26 \\ N500 & \(V_{c}\) & Maximum corner velocity for tool-path movement & mm/min & 1470 & 250 & 550 \\ N600 & \(V_{a}\) & Maximum arc velocity for tool-path movement & mm/min & 7373 & 2939 & 4490 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: CNC parameters for tool-path movement with machining modes. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Description** & **Unit** & **HS** & **HP** & **HQ** \\ \hline Cycle time & sec & 1.935 & 2.655 & 2.064 \\ Dynamic errors & mm & 0.053 & 0.018 & 0.026 \\ Tracking error & mm & 0.007 & 0.003 & 0.001 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Experimental results for three machining modes. HS, HP, and HQ modes, respectively. Actually, the manufacturer provided only a single set of CNC parameters for the commercial CNC machine tools. It was not enough for the different machining requirements. However, the performance of the servo loop and actual machine was fixed and was hard to be tuned, another reason for needing to have quite a domain knowledge to tune the CNC parameters' requirements. Therefore, the operator of the machine cannot easily process the different machining requirements. This paper introduced the relationship of CNC parameters, dynamic errors, and machining modes. The dynamic errors defined the difference of the ideal position for NC code to the actual position for linear scale in this study. According to the anticipated dynamic errors for the three machining modes and feed motion testing by several specified paths' experiment, such as straight, square, and circular paths in actual machine tools, the HS, HP, and HQ modes can be achieved by properly tuning the CNC parameters via the tuning methodology. The experimental results proposed an approach that contained three sets of CNC parameters. The CNC parameters were selected to be larger values of \(J_{p}\), \(A_{p}\), \(V_{c}\), and \(V_{a}\), the path completion time was shortened, and the processing efficiency improved to match the HS mode. However, the corresponding dynamic errors became larger, which sacrificed accuracy and surface quality. On the other hand, the smaller values of CNC parameters resulted in larger completion time and smaller tracking error, and the geometric accuracy was improved to reach the HP mode. The HQ mode dealt with the worse surface quality of the product, caused by feed force for the feed motion. When the feed motion experienced oscillation on the corner or circular paths, the exact \(T_{a}\) reduced the impact of feed force during the high Acc/Dec period. Although the dynamic errors of HQ mode were larger than in the HP mode, the oscillation could be reduced during the feed motion. If there is larger oscillation occurring in the HS mode, in addition to the reduction in \(J_{p}\), \(A_{p}\), \(V_{c}\), and \(V_{a}\), it can also use the \(T_{a}\) to decrease the oscillation for the smooth surface quality of the geometric shape. However, the cycle time became longer, caused by \(T_{a}\) in the HQ mode.