Page 242 - Six Sigma Demystified

222 Six SigMa DemystifieD

• Reaction rules. What is the proper response to the alarms (audio or from a
control chart)? Who should be notified?

Interpretation

See example shown in Table T.4.

Design of experiments (DOe)

A designed experiment consists of planned trials, where factors are set to pre-
defined levels, and one or more response variables are measured. Design of
experiments (DOE) provides an understanding of the sources of variation con-
tributing to a process.

When to Use

Measure Stage
• To estimate the effect of various conditions or equipment on measure-
ment variation

Analyze Stage
• To determine the process drivers, the sources of variation in a process

Improve Stage

• To optimize a process (using response surface designs)

Methodology

Planning
In planning for a designed experiment, one should consider the following issues:

• Why should an experiment be done?
• What responses should be measured? How will responses be measured?
• What factors and interactions will be investigated? What are suitable lev-
els for each?