5. Process Improvement
5.6. Case Studies
5.6.1. Eddy Current Probe Sensitivity Case Study

5.6.1.3.

Interaction Effects

Check for Interaction Effects: Dex Interaction Plot

In addition to the main effects, it is also important to check for interaction effects, especially 2-factor interaction effects. The dex interaction effects plot is an effective tool for this.

Conclusions from the DEX Interaction Effects Plot

We can make the following conclusions from the dex interaction effects plot.

1. Important Factors: Looking for the plots that have the steepest lines (that is, largest effects), we note that:
   • X1 (number of turns) is the most important effect: estimated effect = -3.1025;
   • X2 (winding distance) is next most important: estimated effect = -.8675;
   • X3 (wire gage) is relatively unimportant;
   • All three 2-factor interactions are relatively unimporant.

2. Best Settings: As with the main effects plot, the best settings to maximize the sensitivity are
   (X1,X2,X3) = (+1,-1,+1)

   but with the X3 setting of +1 mattering little.