## 3 Microgroove Tool Preparation and Data Collection
### Surface Roughness Data Collection  
A series of dry turning tests were conducted on the C2-6136 HK CNC lathe. Based on the 304 stainless steel cutting tool supplied by Zigong Cemented Carbide Co., Ltd., the microgroove cutter was prepared. The preparation process and the geometry of the tool rake face are illustrated in Figure 3a. The working angle of the tool geometry is indicated in Table 1. The coating material was AlCrN. The workpiece was a 42 mm diameter AISI 304 stainless steel bar. Table 2 presents the basic performance parameters in relation to the tool material and the workpiece material, and Table 3 indicates the chemical properties possessed by the workpiece. The turning test platform and roughness testing process are shown in Figure 4.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Geometric** & **Tool Angle** & **Rake Angle** & \begin{tabular}{c} **Clearance** \\ **Angle** \\ \end{tabular} & \begin{tabular}{c} **Main Cutting** \\ **Edge Angle** \\ \end{tabular} & \
\begin{tabular}{c} **End Cutting** \\ **Edge Angle** \\ \end{tabular} &
\begin{tabular}{c} **Inclination** \\ **Angle** \\ \end{tabular} \\ \hline Value (\({}^{\circ}\)) & 80 & 8 & 7 & 95 & \(-\)5 & \(-\)5 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Geometric and working angles of the micro-groove tool.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Material** & \begin{tabular}{c} **Density** \\ **g/cm\({}^{2}\)** \\ \end{tabular} & \begin{tabular}{c} **Tensile** \\ **Strength (MPa)** \\ \end{tabular} & \begin{tabular}{c} **Bending** \\ **Strength (MPa)** \\ \end{tabular} & \
\begin{tabular}{c} **Hardness** \\ **Ratio** \\ \end{tabular} &
\begin{tabular}{c} **Poisson’s** \\ **Modulus (GPa)** \\ \end{tabular} \\ \hline Tool & 14.6 & 784.5 & 1.45 & 89.5 HRA & 0.23 & 630–640 \\ Workpiece & 7.93 & 520 & — & 29 HRC & 0.247 & 206 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Tool and workpiece material performance parameters.  
Figure 3: **(a)** Design block diagram of the microgroove tool, microscopic wear pattern of (**b**) the flank face of the conventional tool and (**c**)the microgroove tool.  
As revealed by Figure 4, the surface roughness of the AISI 304 stainless steel bar was tested with the MAHR benchtop probe roughness test platform, and the roughness data shown in Table 4 were obtained. The data were collected at three separate locations along an angle of approximately 120\({}^{\circ}\) and the average roughness value was recorded. Any anomalous data was considered anomalous and was excluded from the average calculation. In order to analyze the surface roughness, the experimental cutting parameters were designed in a way that the cutting speed \(v\) was from 90 m/min to 210 m/min, the feed rate \(f\) varied from 0.05 mm/rev to 0.17 mm/rev, and the cutting depth \(ap\) ranged from 1 to 2 mm.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Trial No.** & \(v\) **(m/min)** & \(f\) **(mm/rev)** & \(ap\) **(mm)** & **Response \(Ra\) (\(\upmu\)m)** & **Type** \\ \hline  
\hline \hline \end{tabular}
\end{table}
Table 4: Experimental data.  
Figure 4: (a) Turning AISI 304 stainless steel test, (b) surface roughness measurement.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Element** & **Si** & **Mn** & **P** & **S** & **Ni** & **Cr** & **C** & **Fe** \\ \hline Content\% & 0.75 & 1.65 & 0.045 & 0.03 & 8.56 & 18.87 & 0.08 & 70.025 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Chemical composition of AISI 304 stainless steel.