In confirmation of the second-order response surface
model, verification tests were conducted at the optimal
condition (Test 1) that was determined by the Taguchi method and two selected conditions (Tests 2 and 3) that
were not carried out in Table 3. In Tests 2 and 3, the
same depth of cut of 15 mm and grain size of 12 mesh
was used. The wheel speed and the table speed were
2100 rpm and 15 m/min and 1500 rpm and 12.5 m/min.
Fig. 8 presented the test results. As shown in Fig. 8,
differences between the predicted geometric error by the
second-order response surface and the measure result by
the experiment were small. So, the second-order
response model was very useful for predicting the
geometric error.