## 4 Orthogonal Tests of Microstructure Parameters  
### Effect of Different Microstructure Parameters on Milling Force on the Front Face of the Cutter  
In the design of microstructure cutting tools, the geometric parameters of groove microstructures significantly influence cutting performance. Research indicates that when the groove texture width (D) is D = 50 \(\upmu\)m, a balanced state between oil retention capacity and stress distribution can be achieved. However D = 90 \(\upmu\)m may induce stress concentration; thus, the recommended range for D is 30 \(\upmu\)m, 50 \(\upmu\)m, and 70 \(\upmu\)m. For microstructure depth (H), a H = 40 \(\upmu\)m configuration demonstrates superior oil film load-carrying capacity, while H = 70 \(\upmu\)m reduces tool rigidity. Consequently, H should be selected from 20 \(\upmu\)m, 40 \(\upmu\)m, and 60 \(\upmu\)m. Regarding microstructure spacing (L\({}_{1}\)), a spacing of L\({}_{1}\) = 120 \(\upmu\)m ensures favorable hydrodynamic lubrication effects between adjacent microstructure units, whereas excessive spacing at L\({}_{1}\) = 150 \(\upmu\)m may cause oil film rupture. Therefore, L\({}_{1}\) should range within 100 \(\upmu\)m, 120 \(\upmu\)m, and 140 \(\upmu\)m. For the distance from microstructures to the cutting edge (L\({}_{2}\)), L\({}_{2}\) = 120 \(\upmu\)m effectively prevents chip adhesion while maintaining edge strength. When L\({}_{2}\) = 160 \(\upmu\)m, the microstructures become too distant from the cutting edge to fully utilize their beneficial effects, making the permissible range for L\({}_{2}\) 80 \(\upmu\)m, 100 \(\upmu\)m, and 120 \(\upmu\)m.  
A four-factor three-level 9-group orthogonal experimental design was established and an orthogonal array, shown in Table 3, was created. The data were imported into Abaqus 2019 software: Abaqus for simulation, and front-cutting force results, presented in Table 4, were obtained using nine distinct experimental parameter sets. Based on the milling force simulation data from Table 4, range analysis was applied to process the data and generate an intuitive analysis table for front-cutting force, as shown in Table 5.  
A range analysis was conducted on Table 6, revealing the order of range values for the four factors as L\({}_{2}\) > H > D > L\({}_{1}\). The magnitude of the range reflects the degree of influence on cutting force, establishing the impact hierarchy: L\({}_{2}\) > H > D > L\({}_{1}\). The findings indicate that L\({}_{2}\) exhibits the highest variance contribution, signifying its significant effect \begin{table}
\begin{tabular}{c c c c c c} \hline
**Elastic** & **Density** & **Poisson’s** & **Specific** & **Thermal** & **Melting** \\
**(GPa )** & **(kg/m3)** & **Ratio** & **Heat** & **Conductivity** & **Point** \\ \hline
199 & 7850 & 0.3 & 500 & 15 & 1400 \\ \hline \end{tabular}
\end{table} 
Table 2: Basic parameters of 304 stainless steel. on cutting force, while L1 has the smallest variance contribution. This ranking aligns with [PERSON]'s [15] research on the relationship between microstructure geometric parameters and milling force. The variation trend of tool parameters' influence on cutting force is illustrated in Figure 6. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Factor** & **D** & **H** & **L1** & **L2** \\ \hline Experiment 1 & 1 & 1 & 1 & 1410.4 N \\ Experiment 2 & 1 & 2 & 2 & 383.6 N \\ Experiment 3 & 1 & 3 & 3 & 362.7 N \\ Experiment 4 & 2 & 1 & 2 & 3 & 392.2 N \\ Experiment 5 & 2 & 2 & 3 & 1 & 406.5 N \\ Experiment 6 & 2 & 3 & 1 & 2 & 356.8 N \\ Experiment 7 & 3 & 3 & 3 & 2 & 407.4 N \\ Experiment 8 & 3 & 1 & 1 & 3 & 394.3 N \\ Experiment 9 & 3 & 2 & 2 & 1 & 415.6 N \\ Average value 1 & 385.567 & 403.333 & 387.167 & 410.833 & \\ Average value 2 & 385.167 & 394.800 & 397.133 & 382.600 & \\ Average value 2 & 405.767 & 378.367 & 392.200 & 383.067 & \\ Variance & 20.600 & 24.966 & 9.966 & 28.233 & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Variance results of milling force.