Statistical Quality Control, 7th Edition

PART 5

Process Design and Improvement with Designed Experiments

Quality and productivity improvement are most effective when they are an integral part of the product realization process. In particular, the formal introduction of experimental design methodology at the earliest stage of the development cycle, where new products are designed, existing product designs improved, and manufacturing processes optimized, is often the key to overall product success. This principle has been established in many different industries, including electronics and semiconductors, aerospace, automotive, medical devices, food and pharmaceuticals, and the chemical and process industries. Designed experiments play a crucial role in the DMAIC process, mostly in the improve step. Statistical design of experiments often is cited as the most important of the Six Sigma tool kit, and it is a critical part of design for Six Sigma (DFSS). The effective use of sound statistical experimental design methodology can lead to products that are easier to manufacture, have higher reliability, and have enhanced field performance. Experimental design can also greatly enhance process development and improvements activities. Designed experiments, and how to use them in these types of applications, are the primary focus of this section.

Factorial and fractional factorial designs are introduced in Chapter 13 with particular emphasis on the two-level design system—that is, the 2^k factorial design and the fractions thereof. ...