Design of Experiments (DOE)

Overview

DOE systematically varies process factors to identify their effects on responses. Full factorial tests all combinations; fractional factorial tests a strategic subset. Identifies main effects and interactions. More efficient than one-factor-at-a-time (OFAT) which misses interactions. Uses ANOVA for analysis.

When to Use

Trigger conditions:

• Identifying which process factors significantly affect quality/yield
• Optimizing process settings for target performance
• Screening many factors to find the vital few

When NOT to use:

• When the process is not stable (stabilize with SPC first)
• For observational data with no ability to manipulate factors

Algorithm