Page 566 - Design for Six Sigma a Roadmap for Product Development

524 Chapter Fourteen

1 2 3 1 2 3 1 2 3 1 2 3
T
3 100
2 50
1
0
P
3 100
2 50
1
0
F
3 100
2 50
1
0
H
3 100
2 50
1
0
N

Figure 14.17 Interaction plot—LS means for TRC.

It is clear that control factors F, H, and P undergo significant interactions
with noise factor N. Actually, these interactions can be used to improve the
robustness toward noise factor; for example, for factor F at level 1, the TRC
[total remaining (metal) concentration] will increase greatly as noise factor
N increases, but for F at level 3, TRC will hardly change with change in
noise factor N, indicating that F at level 3 will deliver robust metal ion
removal despite the noise factors. We can also see that P at level 1 and H at
level 2 give reasonable robustness.
The predicted S/N at optimal control factor level is
39.35 7.05 7.05 5.19 9.54 39.34 0.28 36.20 33.79
T
9
19.69
7.05 9.54 0.28
F 3 5.44
3
7.05 39.34 0.28
H 2 15.37
3
39.35 5.19 0.28
P 1 14.75
3
S/N F 3 P 1 H 2 2T 5.44 14.75 15.37 2( 19.69) 3.82