WHEN DO YOU USE A FACTORIAL DESIGN?

Factorial designs are good preliminary experiments. This article will help you to understand when and how we can use the Factorial Design in DOE

Vinay Kumar Apr 24, 2019 7882 0

WHEN DO YOU USE A FACTORIAL DESIGN?

Factorial designs are good preliminary experiments

A type of factorial design, known as the fractional factorial design, are often used to find the “vital few” significant factors out of a large group of potential factors.
This is also known as a screening experiment
¢Also used to determine curvature of the response surface
FULL FACTORIAL DESIGNS

Every combination of factor levels (i.e., every possible treatment) is measured.
2k design = k factors, each with 2 levels, 2k total runs

33 design = 3 factors, each with 3 levels, 33 = 27 total runs

Every factor effect can be estimated
Can include centre points, but not necessary
2k designs are the most popular
High Level (+1) and Low Level (-1)

Example: 22 design = 4 runs

Run Factor A Level Factor B Level

1 -1 -1

2 -1 +1

3 +1 -1

4 +1 +1

FULL FACTORIAL DESIGNS

Full factorials can also allow factors to have different number of levels

213241 = 4 factors total (sum of exponents) One factor has 2 levels, two have 3 levels, one has 4 levels Total of 2*3*3*4 = 72 runs