# Application of 3D Imaging for Analyzing the Chip Groove Shapes of Cutting Inserts
## 3 Results and Discussion
It was also observed that for both tested chip-former shapes, the increase in feed rate increased the degree of chip groove filling. Table 5 presents the results of the average values of the breakage coefficient of _Cch_ chips, with a description of the shape of the chips, and values of the \(S/N\) parameter obtained in the test systems. A simplified method of chip classification was adopted, according to which the chip breakage index _Cch_ takes values from 0 to 1. Lower _Cch_ values represent better chip breakability. Table 6 presents a statistical analysis of the test results. \begin{table}
\begin{tabular}{c c c c c c c} \hline \(a_{p}\) & \(f\) & \(K\) & **Chip** & **Photo** & _Cch_1  & _S/N_ & **Chip Description** \\ (mm) & (mm/rev) & (deg) & **Former** & & & \\ \hline
0.25 & 0.1 & 60 & SF & 1.0 & 0.28 & Long, spiraled, tnacceptable \\
0.25 & 0.2 & 90 & SGF & 1.0 & 0.28 & Long, spiraled \\ Unacceptable \\ \hline \end{tabular}
\end{table} 
Table 5: Results for measurements of _Cch_ (mean values). Figure 9: Rake face with visible wear resulting from the contact between the chip and the cutting tool. (**a**) Rake face of the insert with the SF chip former. (**b**) Rake face of the insert with the SGF chip former. The analysis of the data showed that the feed rate had the most significant influence on the chip form and the average values of the chip-breaking coefficient \(C\!ch\) in the longitudinal turning process. According to statistical analysis, the parameters with a higher \(F\) value had a greater influence on the responses represented in Table 5. Moreover, the depth of cut \(a_{p}\), feed \(f\) and major cutting-edge angle \(K\) contributed 45.7%, 30%, and 17.6% of the response to the chip-breaking index value \(C\!ch\) when the test alloy was turned. The chip-former type ranked last. Figure 10 graphically shows the influence of individual variables on the average value of the chip breakability index \(C\!ch\). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Source** & \(\mathbf{DF}\) & \(\mathbf{Seq}\)\(\mathbf{S}\) & \(\mathbf{Adj}\)\(\mathbf{S}\) & \(\mathbf{Adj}\)\(\mathbf{MS}\) & \(\mathbf{F}\) & \(\mathbf{p}\) \\ \hline \(a_{p}\) (mm) & 3 & 0.1365 & 0.1365 & 0.0455 & 13.68 & 0.196 \\ \(f\) (mm/rev) & 1 & 0.0897 & 0.0897 & 0.0897 & 26.98 & 0.121 \\ \(K\) (deg.) & 1 & 0.0525 & 0.0525 & 0.0525 & 15.77 & 0.157 \\ Chip former & 1 & 0.0164 & 0.0164 & 0.0164 & 4.94 & 0.269 \\ Residual Error & 1 & 0.0033 & 0.0033 & 0.0033 & & \\ Total & 7 & 0.2984 & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Analysis of variance for mean values of the chip breakability index \(C\!ch\). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \(a_{p}\) & \(f\) (mm/rev) & \(K\) (deg) & Chip & Photo & \(C\!ch\)1  & \(S\!/N\) & Chip Description \\ \hline
0.50 & 0.1 & 60 & SGF & 0.7 & 3.10 & Helical/tubular Acceptable \\
0.50 & 0.2 & 90 & SF & 0.6 & 4.44 & Helical/tubular Acceptable \\
0.75 & 0.1 & 90 & SF & 0.8 & 1.43 & Long, tangled Unacceptable \\
0.75 & 0.2 & 60 & SGF & 0.6 & 4.44 & Helical/tubular Acceptable \\
1.00 & 0.1 & 90 & SGF & 0.9 & 0.85 & Long, spiraled, tangled Unacceptable \\
1.00 & 0.2 & 60 & SF & 0.4 & 7.96 & Helical/tubular Acceptable \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._Graphical analysis of the results showed that an increase in the value of cutting parameters, i.e., depth of cut and feed, affects the change of chip form from unfavorable to acceptable and correct. For depths of cut \(a_{p}<0.5\) mm and low feed rates value, there is no chip-breaking process, and long, unacceptable chips are obtained in the machining process. Further increasing the depth of cut results in an acceptable chip form. The parameter that has the greatest impact on the change in the form of chips is the feed value, as evidenced by the large angle of inclination of the line presented in the diagram. Moreover, a lower major cutting-edge angle (\(K=60^{\circ}\)) supports the chip-formation process and leads to a more favorable chip form.