## 3 Effects of Process Parameters on the Performance of the Printing Layer
### Ultrasonic Power  
The experimental design and result analysis are shown in Table 6 and Figure 6. Under the action of ultrasonic vibration, the melt pool of experimental groups 2-4 was relatively uniform, with no significant changes in width B and height H. The melt depth increased slightly, which is a result of the thermal effect of ultrasonic vibration and other factors. Thus, the selected ultrasonic vibration power level values are 5%, 10%, and 15%. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \(\mathbf{P_{1}}\) & \(\mathbf{v_{s}}\) & \(\mathbf{v_{r}}\) & \(\mathbf{P_{s}}\) & \(\mathbf{B}\) & \(\mathbf{H}\) & \(\mathbf{h}\) & & \\  & **(W)** & **(mm/s)** & **(r/min)** & **(\%)** & **(mm)** & **(mm)** & **(mm)** & **(mm)** & \(\Upsilon\)** & \(\eta\) \\ \hline
1 & 235 & 6 & 1.8 & 0 & 0.838 & 0.312 & 0.015 & 2.77 & 4.5 \\
2 & 235 & 6 & 1.8 & 5 & 0.861 & 0.304 & 0.017 & 2.83 & 5.5 \\
3 & 235 & 6 & 1.8 & 10 & 0.873 & 0.303 & 0.018 & 2.88 & 5.6 \\
4 & 235 & 6 & 1.8 & 15 & 0.871 & 0.298 & 0.018 & 2.92 & 5.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Ultrasonic power single-factor experiment design and results. Figure 5: Influence of the powder feeding speed on printing layer: (**a**) The melt width, melt height and melt depth; (**b**) the shape factor and the dilution rate. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \(\mathbf{P_{1}}\) & \(\mathbf{v_{s}}\) & \(\mathbf{v_{r}}\) & \(\mathbf{P_{s}}\) & \(\mathbf{B}\) & \(\mathbf{H}\) & \(\mathbf{h}\) & & \\  & **(W)** & **(mm/s)** & **(r/min)** & **(\%)** & **(mm)** & **(mm)** & **(mm)** & **(mm)** & \(\Upsilon\)** & \(\eta\) \\ \hline
1 & 235 & 6 & 1.2 & 10 & 0.908 & 0.283 & 0.016 & 3.21 & 5.3 \\
2 & 235 & 6 & 1.4 & 10 & 0.911 & 0.298 & 0.017 & 3.06 & 5.4 \\
3 & 235 & 6 & 1.6 & 10 & 0.905 & 0.315 & 0.018 & 2.87 & 5.4 \\
4 & 235 & 6 & 1.8 & 10 & 0.873 & 0.303 & 0.018 & 2.88 & 5.6 \\
5 & 235 & 6 & 2.0 & 10 & 0.871 & 0.310 & 0.017 & 2.81 & 5.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Powder feeding speed single-factor experiment design and results. The level values of each factor established in the single-factor experiment are shown in Table 7.  
The K value in the range analysis table is the sum of the experimental data for a certain factor at a certain level, while the K avg value is the average value of the corresponding K. The R is the difference between the maximum and minimum values of the mean. The size of R reflects one factor that has the most significant impact on the shape coefficient \(\gamma\). The larger the R, the greater the impact. The smaller the R, the more stable it is, and the less significant the impact. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Level**} & **A** & **B** & **C** & **D** \\  & **Laser Power P\({}_{\text{I}}\)** & **Sweep Speed v\({}_{\text{s}}\)** & **Powder Feeding** & **Ultrasonic Power** \\  & **(W)** & **(mm/s)** & **Speed v\({}_{\text{r}}\)** & **Percentage P\({}_{\text{s}}\)** \\  & & & **(r/min)** & **(\%)** \\ \hline
1 & 220 & 5 & 1.7 & 5 \\
2 & 235 & 6 & 1.8 & 10 \\
3 & 250 & 7 & 1.9 & 15 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Orthogonal experiment factor level. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**No.** & **A** & **B** & **C** & **D** & **B (mm)** & **H (mm)** & \(\gamma\)** \\ \hline
1 & 220 & 5 & 1.7 & 5 & 0.615 & 0.501 & 1.23 \\
2 & 220 & 6 & 1.9 & 10 & 0.713 & 0.426 & 1.67 \\
3 & 220 & 7 & 1.8 & 15 & 0.590 & 0.225 & 2.62 \\
4 & 235 & 5 & 1.9 & 15 & 0.977 & 0.592 & 1.64 \\
5 & 235 & 6 & 1.8 & 5 & 1.410 & 0.543 & 2.60 \\
6 & 235 & 7 & 1.7 & 10 & 0.891 & 0.403 & 2.21 \\
7 & 250 & 5 & 1.8 & 10 & 0.928 & 0.481 & 1.93 \\
8 & 250 & 6 & 1.7 & 15 & 0.882 & 0.410 & 2.15 \\
9 & 250 & 7 & 1.9 & 5 & 0.908 & 0.435 & 2.09 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: L9(34) orthogonal experiment table and results.