This study investigated the optimization ofCNCturning operation parameters for SKD11 (JIS)
using the Grey relational analysis method. Nine experimental runs based on an orthogonal
array of Taguchi method were performed. The surface properties of roughness average and
roughness maximum as well as the roundness were selected as the quality targets. An
optimal parameter combination of the turning operation was obtained via Grey relational
analysis. By analyzing the Grey relational grade matrix, the degree of influence for each
controllable process factor onto individual quality targets can be found. The depth of cut
was identified to be the most influence on the roughness average and the cutting speed
is the most influential factor to the roughness maximum and the roundness. Additionally,
the analysis of variance (ANOVA) is also applied to identify the most significant factor; the
depth of cut is the most significant controlled factors for the turning operations according
to the weighted sum grade of the roughness average, roughness maximum and roundness.