The effect of each parameter on the S/N ratio at different levels
could be separated because the experimental design was orthogonal
[18]. The mean of the S/N ratio for each level of the welding
parameters was summarized and is shown in Figs. 4 and 5. According
to the reading of these diagrams based on the Taguchi method,
all four parameters had a significant effect on the quality metric.
The highest levels for the weld area and penetration were
V3I3S1G2 and V3I3S1G3, respectively