## 3 Results and Discussion  
### Effect of Process Parameters on the Single-Track Quality  
Analysis of the results of orthogonal and interaction experiments use the range method. The results and analysis of the orthogonal experiment are given in Figure 6 and Table 4, where \(I\), _II_, and _III_ represent the average dilution rate values of the three levels of parameters, respectively, \(K_{1}\), \(K_{2}\), and \(K_{3}\) represent the average width-height ratio of three levels of  
Figure 5: Deposition strategies’ optimization of the gear tooth: (I-1) hot lap joint, (I-2) cold lap joint, (I-3) optimized cold strategy, (II-1) co-directional scanning, (II-2) reverse scanning, (III-1) interlayer scanning perpendicular to the axial direction, (III-2) interlayer scanning parallel to the axial direction, (III-3) scanning directions of the two adjacent layers are perpendicular to each other. parameters, respectively, and R represents the range. The magnitude of the range directly reflects the degree of influence of the factor on the parameter. Too low \(\beta\) will lead to poor metallurgical bonding between the current layer and the substrate or former coating. While too high dilution \(\beta\) will lead to serious remelting and influence the forming stability. The quality of the cladding layer is better when the dilution ratio is 20-30% [32]. When \(\lambda\)\(\gg\)2, deposition efficiency is low. When \(\lambda\)\(<\) 2, the molten pool will exhibit high collapse sensitivity [33]. The \"Rank\" in Table 4 indicates the degree of the factor influence of the four parameters (\(P\), \(V_{S}\), \(V_{P}\), \(Q\)) on \(\beta\) and \(\lambda\). Based on the dependent variables \(\beta\), \(\lambda\), and the results of the analysis of the range method in Table 4, the order of importance of the effect of each parameter on \(\beta\) is \(R_{Q}>R_{V_{S}}>R_{V_{P}}>R_{P}\), and the order on \(\lambda\) is \(R_{Q}>R_{V_{S}}>R_{P}>R_{V_{P}}\). However, each parameter influences \(\beta\) and \(\lambda\) in a different order, it can be concluded that \(Q\) and \(V_{S}\) are major factors, and \(P\) and \(V_{P}\) are minor factors. The following parameters should be chosen: \(Q\) = 7 L/min, \(V_{S}\) = 10 mm/s, \(V_{P}\) = 0.8 r/min, \(P\) = 380 W, according to the results of the dilution rate range analysis. This situation is not special in orthogonal experiments [34]. The effects of different levels of each parameter on \(\beta\) and \(\lambda\) are fitted in Figure 6. From Figure 6, the \(Q\) ranges from 7 to 7.5 L/min, the \(V_{s}\) ranges from 8 to 10 mm/s, the \(V_{P}\) ranges from 6 to 7 r/min, and the \(P\) of 380 W is suitable for both \(\beta\) and \(\lambda\). So, interaction experiments were established and analyzed to further optimize the uniform parameters on \(\beta\) and \(\lambda\). As shown in Table 5, \(C_{1}\) and \(C_{2}\) represent the average dilution rate value of the two levels of parameters, respectively. The degree of influence of the interaction experiment on each parameter is \(Q\)\(>\)\(Q\)\(\times\)\(V_{S}\)\(>\)\(P\)\(>\)\(P\)\(\times\)\(V_{P}\)\(>\)\(Q\)\(\times\)\(P\)\(>\)\(V_{S}\)\(\times\)\(P\)\(>\)\(V_{P}\)\(>\)\(V_{S}\)\(\times\)\(V_{P}\)\(>\)\(V_{S}\). The parameter of \(Q\)\(\times\)\(V_{S}\) and \(P\)\(\times\)\(V_{P}\) have very obvious interactions and the interaction of \(Q\)\(\times\)\(P\) is not obvious, as shown in Figure 7. The coatings with a dilution rate of 20% exhibited good bonding properties, according to the previous study [32]. Therefore,  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \(P\) (W) & \(V_{S}\) (mm/s) & \(V_{P}\) (r/min) & \(Q\) (L/min) & Rank \\ \hline \(I\) & 0.295 & 0.376 & 0.345 & 0.292 & \\ \(II\) & 0.288 & 0.325 & 0.302 & 0.194 & The rank of \(\beta\) \\ \(III\) & 0.345 & 0.227 & 0.280 & 0.441 & \(R_{Q}>R_{V_{S}}>R_{V_{P}}>R_{P}\) \\ \(R\) & 0.057 & 0.150 & 0.  
level 2 for \(Q\), level 2 for \(V_{S}\), level 1 for \(P\), and level 1 for \(V_{P}\), were selected in this study.