In order to assess the influence of the different factors on a response,
the means and S/N ratios for each one was calculated. The
signals were indicators of the effect on the average response and
the noise was a measure of the influence on the deviation from
the average response, which accounts for the sensitiveness to the
noise. Basically, the higher the weld area and penetration depth
in the GMAW process, the better the welding performance [21].
Therefore, the S/N ratio was chosen according to the criterion
‘the-larger-the-better’ in order to maximize the response. The corresponding
S/N ratios are shown in Table 5