Case Studies and White Papers


Computer-Aided Tools for Optimal Mixture Design

Published: November 1999
Authors: Mark Anderson, Patrick Whitcomb

See how statistically-based mixture design of experiments (DOE) make breakthrough improvements in cost and performance of paints and coatings. Dedicated DOE software exhibit make it easy to create optimal designs that handle any combination of mixture components, processing factors (such as time or temperature) and categorical variables (such as supplier and material type). They easily manipulate almost any number of responses in powerful optimization tools that reveal "sweet spots" - the operating windows meeting all specifications at minimal cost.

Publication: Paint & Coatings Industry

Published: July 1999
Authors: Mark Anderson, Shari Kraber

Quality managers who understand how to apply statistical tools for design of experiments (DOE) are better able to support use of DOE in their organizations. Ultimately, this can lead to breakthrough improvements in product quality and process efficiency.

Publication: Quality Digest

Revealing Interactions From Fractional DOEs

Published: January 1999
Authors: Mark Anderson, Shari Kraber

Fractional two-level factorials are a powerful tool for making significant improvements to product quality and process efficiency. Unfortunately, this approach to design of experiments (DOE) may alias the main effects with their interactions. Then it is no longer clear which factors truly influence the process. In part 1, this paper illustrates the use of graphical technique for the viewing alternative aliased interactions. The graphical procedure enhances, but does not remove, the guesswork required when a highly-fractional design produces significant effects. The only sure way to pin down the actual effects will be to perform follow up experiments, which will be discussed in Part 2. A technique called "foldover" is tailor-made for de-aliasing effects. This sequential approach to DOE offers a great deal of flexibility to the quality engineer.

Publication: ASQC 52nd Annual Quality Congress Proceedings 5/98

Published: April 1998
Authors: Mark Anderson, Patrick Whitcomb

A version of this article appeared in Chemical Engineering Progress. (chem-2.pdf 56KB) April 1998.

(Click on http://www.statease.com/pubs/ital-favform.pdf for an Italian translation 435KB.

Also see a PDF of this article as published in Ric-Mach Chimica News, http://www.statease.com/pubs/sixsigma.pdf . (sixsigma.pdf 129KB) June 2004.)

Publication: Chemical Engineering Progress

Statistical Design of Experiments for Quality Improvements of Fertilizer Products

Published: April 1998
Authors: Mark Anderson, P.K. Battacharjee, Patrick Whitcomb

Statistical tools, especially design of experiments (DOE), provides the means for quality improvement of diammonium phosphate (DAP) and related fertilizer products. Depletion of high grade phosphate ores in Florida and elsewhere makes it increasingly difficult to meet customer specifications for nitrogen content of DAP. Urea or ammonia can be used as nitrogen supplements, but this adds cost to the final product. This paper lays out a special form of DOE, called two-level factorial design, which helped to maximize nitrogen content in DAP and make it less susceptible to impurities in lower grade phosphates.

Publication: American Institute of Chemical Engineering Proceedings

Find The Most Favorable Formulations

Published: April 1998
Authors: Mark Anderson, Patrick Whitcomb

Design of experiment (DOE) tools provide an efficient means for you to optimize your process. But, you shouldn't restrict your studies only to process factors. Adjustments in the formulation may prove to be beneficial, as well. A simple but effective strategy of experimentation involves: 1. Optimizing the formulation via mixture design; and 2. Optimizing the process with factorial design and response surface methods. This article shows you how to apply DOE methods to your formulation. A case study gives you a template for action.

Publication: Chemical Engineering Progress

Design of Experiments Strategies

Published: January 1998
Authors: Mark Anderson, Patrick Whitcomb

The traditional approach to experimentation requires changing only one factor at a time (OFAT). However, the OFAT approach does not provide data on the interactions of factors, a likely occurrence with processes. This white paper lays out the tried-and-true "SCO" strategy of screening and characterization via two-level factorial design of experiments (DOE), followed, if needed, by response surface methods (RSM) for process optimization.

Publication: Chemical Processing

Published: January 1998
Author: Mark Anderson

Inspirational examples of DOE being applied in non-manufacturing, including sales and marketing (particularly for web-page development), but also billing, education of medical patients and many other business processes that can be quickly improved (and most effectively!) via multifactor testing methods.

Mixing it up with Computer-Aided Design

Published: November 1997
Authors: Mark Anderson, Patrick Whitcomb

With the latest computer software, today's formulators can take advantage of a powerful tool: design of experiments (DOE) for mixtures. DOE methods use test arrays that produce maximum information from minimal runs. Industrial experimenters typically turn to two-level factorials as their first attempt at DOE. However, mixture design accounts for the dependence of response on proportionality of ingredients where factorial design does not. If you formulate chemicals, food or other products, consider using mixture design rather than factorials or related optimization methods. To show you how, follow along as we conduct a kitchen chemistry experiment on pound cake

Publication: Today's Chemist at Work

Breakthrough Improvements with Experiment Design

Published: June 1997
Authors: Mark Anderson, Patrick Whitcomb

In many rubber and plastics processes, powerful interactions affect final performance. You will not discover interactions when you change only one factor at a time. Proper design of experiments (DOE) will reveal interactions that can help you achieve breakthrough improvements in process efficiency and product quality. The big gains come from a simple form of DOE called two-level factorial design. This approach to experimentation has proven helpful in controlling part shrinkage, but it can be applied to any measurable response. In this article you will be given the primary details from an engineering perspective.

Publication: Rubber & Plastics News