Statistical Quality Control, 7th Edition

13 Factorial and Fractional Factorial Experiments for Process Design and Improvement

CHAPTER OUTLINE

13.1   WHAT IS EXPERIMENTAL DESIGN?

13.2   EXAMPLES OF DESIGNED EXPERIMENTS IN PROCESS AND PRODUCT IMPROVEMENT

13.3   GUIDELINES FOR DESIGNING EXPERIMENTS

13.4   FACTORIAL EXPERIMENTS

13.4.1   An Example

13.4.2   Statistical Analysis

13.4.3   Residual Analysis

13.5   THE 2^k FACTORIAL DESIGN

13.5.1   The 2²Design

13.5.2   The 2^k Design for k ≥ 3 Factors

13.5.3   A Single Replicate of the 2^k Design

13.5.4   Addition of Center Points to the 2^k Design

13.5.5   Blocking and Confounding in the 2^k Design

13.6   FRACTIONAL REPLICATION OF THE 2^k DESIGN

13.6.1   The One-Half Fraction of the 2^k Design

13.6.2   Smaller Fractions: The 2^k-p Fractional Factorial Design

Supplemental Material for Chapter 13

S13.1   Additional Discussion of Guidelines for Planning Experiments

S13.2   Using a t-Test for Detecting Curvature

S13.3   Blocking in Designed Experiments

S13.4   More about Expected Mean Squares in the Analysis of Variance

The supplemental material is on the textbook Website www.wiley.com/college/montgomery.

CHAPTER OVERVIEW AND LEARNING OBJECTIVES

Most experiments for process design and improvement involve several variables. Factorial experimental designs, and their variations, are used in such situations. This chapter gives an introduction to factorial designs, emphasizing their applications for process and quality improvement. Designed experiments are widely used in the DMAIC process, ...