Mixture Experiment Research at DuPont---Contributions and Learnings

• Activity Number: 82
• Type: Invited
• Date/Time: Monday, August 8, 2005 : 8:30 AM to 10:20 AM
• Sponsor: Section on Quality and Productivity
• Author(s): Ronald D. Snee*+
• Companies: Tunnell Consulting
• Keywords: Mixture experiment design ; Computer-aided experimental design ; analysis of mixture experiments ; response surfaces

Abstract

In the late 1960s, DuPont experimented with a number of products including paint, gasoline additives, and plastics created by mixing ingredients or components. Mixtures were not new to DuPont. Its first product, black powder, was a mixture of three components: saltpeter, charcoal, and sulfur. The only experimental design tools available were the result of the work of Scheffé, McLean, and Anderson. From the late 1960s until the early 1980s, statisticians at DuPont made several advances to the design, analysis, and interpretation of mixture experiments. These advances were needed because the available tools were not adequate to successfully deal with the mixture problems encountered. This presentation traces these developments, many of which are in common use today, detailing the contributions and learning that can be gleaned from this body of work. Topics covered include dealing with irregular experimental spaces resulting from constraints on the components of the mixture, computer-aided design of experiments, and interpretation of mixture response surfaces.