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Tutorial #4: Surface Plots

In order to get a graphical representation of our model, we are going to create a surface plot. To start the process select "DOE PRO" - "Graphs and Optimization" - "Interaction, Surface, Contour Plot…" from the Excel menu bar.

 

We now need to tell DOE PRO how we want the surface plot created. In the "Create Graph Options" window, change the settings to look like the window below. This will make DOE PRO create a surface plot of "Stop Angle" vs. "Cup Angle" for the Red Ball response with Pull Back Angle set at 170 Degrees. Click the "Create and Exit" button.

Graph Options

 

The resulting surface plot is shown below. Note that by default, Excel will only use four colors to color the surface plot.

 

Surface Plot

 

If you would like to increase the number of colors, double click on the legend (where it shows the colors and numbers). The "Format Legend" window should pop up. Click on the "Scale" tab and change the "Major Unit" to "5". Click on the "Ok" button.

 

Doe Pro Format Legend

 

The resulting surface plot is a little easier to read.

 

Surface Plot refined

 

The surface plot allows us to see a graphical representation of how the "Stop Angle" and "Cup Angle" affect the output together. We can also approximate where the maximum and minimum occur by finding the highest and lowest location on the contour.

 

As powerful as the surface plot is, it does have limitations.

  1. The surface plot only shows two inputs at one time.
  2. The surface plot only shows one output at a time.
  3. It is not easy to find exact relationships between input values and output values.

In order to overcome these limitations we need to use the Multiple Response Optimizer.