Case Studies and White Papers

Published: July 2000
Author: Tom Cheyney

PRI Automation has been meeting wafer transport traffic challenges through the manufacturing processes by using designed experiments software. The firm designed and built overhead automated material handling systems (AMHSs) that transport wafers through the manufacturing lines of Intel, Motorola, and other global semiconductor giants. PRI has succeeded partly by discovering how rapidly transport vehicles ought to travel in order to minimize transit time between process steps while increasing AMHS throughput using Design-Expert.

Publication: MICRO Magazine

Published: July 2000
Author: PRI Automation

Article in Micro magazine.

Publication: Micro Mag.

Published: April 2000
Authors: Jennifer Borkovich, Lisa Surowitz

Coding Products’ Hot Ink Rollers, pre-inked foam rollers measuring approximately one inch in diameter, are impregnated with ink before being sent to our wide variety of customers. Before they used DOE to improve the rollers, a customer might get 65,000 impressions from one of our rollers, while the next roller would produce anywhere from 30,000 to 120,000 impressions. Consistency in the number of impressions is crucial because it allows customers to schedule roller changes. Using DOE, the scientists revealed which factors were most critical, leading to decreased manufacturing time, improved productivity, and increased capacity.

Publication: Paint & Coatings Industry

Published: April 2000
Author: Raquel Wager

Forma Scientific’s cooling unit is a critical component that sits within a blood analyzer being built by Ortho-Clinical Diagnostics, a Johnson & Johnson company. To do its job well, the cooler’s specification called for a constant 6°C temperature with enough capacity to remove heat introduced during operation. Scientists used DOE to identify several factors and interactions that were affecting its performance and prove that cooling coil temperature could be decreased while still providing ample refrigerating capacity. The savings from this finding exceeded $18,000 because an environmentally controlled testing facility was not needed.

Publication: Air Conditioning Heating Refrigeration News

Practical Aids for Teaching Experimental Designs

Published: February 2000
Authors: Madhuri Mulekar, Mark Anderson, D.W. McCarmik, Pat Spagon

Design of Experiments (DOE) is an essential tool for product and process improvement. Good software now makes the set up for design and analysis of experiments very easy, but many engineers and/or non-statisticians feel intimidated by statistical outputs. For that reason, non-statisticians need training in proper designing and conducting of experiments. Ideally the DOE training is best when provided on a just-in-time basis - prior to actually doing an experiment. However, an in-class experiment is a reasonable substitute for real-life experiments. It is important for technicians to gain an understanding of designed experiments so that mistakes made in conducting the experiment are reduced and the data is collected more correctly and accurately from the experiments. Managers read and possibly edit reports, and make decisions based on the experiments run by technicians and engineers. An understanding of design and analysis techniques helps them identify any problems with the experiment or the results. At SEMATECH, there are two general audiences. The first is comprised of project engineers. They are responsible for designing and conducting experiments to determine if the project they work on meets its goals. Most of them take an eight day long course on designed experimentation that covers many basic concepts. The second group is comprised of project managers and technicians. This group does not have as great a need for the details of experimental design as the first group. Project managers manage the project engineers, and the technicians carry out the experimentation under the direction of the project engineers. The technicians also assist the project engineers in running the equipment on which the experiments are conducted. This helps ensure that experimental runs and data collection proceed smoothly. The project managers oversee all aspects of the experiment and must understand the outcomes of the experiments too. So the managers must provide adequate resources for the experiment, must know why certain designs are used, and be able to interpret and critique the analysis intelligently. The emphasis of the exercise is to motivate, illustrate and provide hands on experience with the methodologies and analysis techniques discussed in class.

How to Design and Analyze Mixture Designs that Include Process Factors and/or Categorical Variables

Published: January 2000
Authors: Mark Anderson, Patrick Whitcomb

The latest versions of dedicated DOE software exhibit more versatility than ever before 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). These computer programs easily manipulate almost any number of responses in powerful optimization routine that reveal "sweet spots" - the operating windows that meet all specifications at minimal cost. In this paper, we review the basic principles of mixture design. Then we apply state-of-the-art tools for optimal design to the formulation of a coating.

Publication: Industrial Statistics in Action 2000

Eliminate Nuisance Variability with a Latin Square Design

Published: January 2000
Authors: Douglas Montgomery, Mark Anderson

Case study from Douglas Montgomery's <em>Design and Analysis of Experiments, 4th Edition</em>, John Wiley, Example 5-4 on page 196.

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