In memory of our teachers, colleagues, friends:
Genichi Taguchi
Yuin Wu

What is Robust Optimization? Put simply, it's a method to improve robustness using low-cost variations of a single, conceptual design. Jim Pratt, a former Vice-President of ITT, once said that using Robust Optimization on manufacturing processes was like “picking gold up off the floor!” Robust Optimization uses Robust Assessment to estimate the robustness of low-cost combinations of design parameter (control factor) values with a single conceptual design in order to discover the most robust combination of design parameter (control factor) values. A design parameter is called a control factor in Robust Optimization. A control factor value is a quantitative or qualitative level of a variable contained within the selected conceptual design. In mechanical designs, dimensions, radii, and material properties are typical control factors. In electrical designs, resistance, impedance, and capacitance are frequent control factors. In chemical processes, temperatures, rate of temperature change, pressures, pressure rate, reagents, and catalysts are common control factors.

In product or process development, Robust Optimization occurs after system (conceptual) design is complete and before the conceptual design is adjusted to meet requirements. Robust Optimization is best conducted before the requirements are defined.

Robust Optimization as a first step discovers a robust, low-cost combination of control factor values. This combination may not meet or even be close to meeting the design requirements. However, Robust Optimization as a second step discovers how to adjust that low-cost combination of control factor values so that the product can meet requirements. That very stable combination of control factor values is adjusted or “tuned” so that the product or process can easily meet requirements or specifications.

Selection of design concept that is robust is critical. Robust Optimization and assessment allow us to evaluate how robust the new concept is quickly so that we can try many concepts. We don't want to pass poor concepts through design gates. We need to detect bad design early. If we are going to fail, it is better to fail early so we can move on to the next concept quickly.

The benefits of Robust Optimization include such things as faster product development cycles; faster launch cycles; fewer manufacturing problems; fewer field problems; lower-cost, higher performing products and processes; and lower warranty. All these benefits can be realized if Engineering and product development leadership of automotive and manufacturing organizations leverage the power of using Robust Optimization as a competitive weapon.

The overarching benefit, however, is to create a group of technical employees with skills that produce results which dazzle your customers and the general public. Become the organization that produces the highest quality products at the lowest cost. Become the organization that is the first or second choice of every top-ranked engineering graduate in the world. Become the organization that is featured in the trade magazines as the innovator with rock solid quality and a winning value proposition for your customers.

The main objective of this book is to introduce engineering executives and leaders to the technical management strategy of Robust Optimization. In the first three chapters, we will discuss what the strategy entails, Eight Steps for Robust Optimization and Robust Assessment, and how to lead it in a technical organization with an implementation strategy. Another objective of this book is to demonstrate the application of Robust Optimization to automotive applications using real-life case studies from leading automotive organizations.

In this book, we define Robust Optimization and demonstrate how these techniques can be applied to build into manufacturing organizations especially with automotive industry applications; that Robust Optimization creates the flexibility that minimizes product development cost, reduces product time-to-market, and increases overall productivity. For the past 40 years thousands of companies throughout the world have been using the methodology ‘Robust Optimization’ of the late Dr. Genichi Taguchi, the quality pioneer, and have obtained positive results. Some organizations have integrated this new powerful methodology into their corporate culture. The benefits these organizations have achieved are phenomenal.

In this groundbreaking book, we have organized 19 successfully implemented best case studies from automotive original equipment manufacturers such as General Motors, Ford, Chrysler, Nissan, Isuzu, and Mazda as well as automotive suppliers like Bosch, Delphi, and Alps Electric. We have been working for past decades with all types of clients in automotive, manufacturing, healthcare, food, aerospace and other industries. Our firm ASI Consulting Group, LLC, headquartered in Bingham Farms, Michigan, USA, is very fortunate in that clients have been continuously putting their trust in our team. Most importantly, clients share their success stories at our annual client conferences. We are also fortunate to have other organizations from Europe and Asia to attend our annual conference and present their success stories on the application of Robust Optimization. ASI has thousands of case studies in its database and it is therefore impossible to feature all case studies in this book. However, we have included some of the very best of these case studies, keeping in mind the variety of applications of Robust Optimization.

There are many books available, mostly in English and Japanese, which include some automotive case studies. However, there is no book to date which presents best practices from around the globe on Robust Optimization in the automotive industry, and manufacturing industry in general. This is the first book to focus on the automotive application of Robust Optimization. In the organizations where Robust Optimization is extremely successful, senior leadership has an understanding of the significant impact of the applications and therefore support for implementation is highly encouraged or mandatory. In the United States, Asia, and Europe, hundreds of organizations have unfortunately been using Robust Optimization incorrectly, but those that have used the methodology correctly have been saving millions of dollars. Those organizations that have not been utilizing this powerful method may have not being doing so because of their lack of management understanding and misconceptions about its complexity. This book will therefore be a must read for any engineering manager or engineer because of its ability to clarify these generalized misconceptions.

This is the first book that features case studies from all four critical areas of Robust Optimization of an automotive organization:

1. Vehicle Level Optimization
2. Subsystems Level Optimization by Original Equipment Manufacturers (OEMs)
3. Subsystems Level Optimization by Suppliers
4. Manufacturing Process Optimization.

We also hope that this book provides direct learning techniques to the vast variety of industries and educational institutions and that it provides a formula for instant knowledge on areas that apply to the reader and his/her organization.

This book is for engineers and managers who are working in the design, product, manufacturing, mechanical, electrical, process, and quality areas; all levels of management especially in the product development area; and research and development personnel and consultants. Almost all the case studies featured in this book make it suitable as a training and education guide, as well as serving both students and teachers in engineering colleges. We strongly feel that all libraries with technical sections will greatly benefit from having this book in their collection.

Subir Chowdhury
Shin Taguchi
July 31, 2015

The authors gratefully acknowledge the efforts of all who assisted in the completion of this book:

1. To all of the contributors and their organizations for sharing their successful case studies.
2. To the ASI Consulting Group, LLC and all its employees and partners worldwide.
3. To our colleagues and friends, Alan Wu, Brad Walker, Michael O'Ship, Matt Gajda, Michael Holbrook, Brian Bartnick, Bill Eureka, Jay Eleswarpu, Joe Smith, and Francois Pelka for effectively promoting Robust Optimization each day.
4. To our colleague Jodi Caldwell for her hard work on the preparation of the manuscript.
5. To our two retired colleagues and friends, Jim Quinlan and Barry Bebb for enriching us over the past two decades.
6. To Paul Petralia, our editor at Wiley, for his dedication and guidance to make the book better.
7. To Liz Wingett, our project editor at Wiley, for her hard work making the book published on time.
8. To Martin Noble, our copy editor at Wiley, for his dedicated efforts toward refining the manuscript.
9. To Anne Hunt, Associate Commissioning Editor at Wiley for her work on the book.
10. To Sandra Grayson, Associate Book Editor, for her work on the book.
11. Finally, this book never would have been materialized without the continuous support of our wonderful wives Malini Chowdhury and Junko Taguchi.

Subir Chowdhury has been a thought leader in quality management strategy and methodology for more than 20 years. Currently Chairman and CEO of ASI Consulting Group, LLC, he leads Six Sigma and Quality Leadership implementation, and consulting and training efforts. Subir's work has earned him numerous awards and recognition. The New York Times cited him as a “leading quality expert”; BusinessWeek hailed him as the “Quality Prophet.” The Conference Board Review described him as “an excitable, enthusiastic evangelist for quality.”

Subir has worked with many organizations across diverse industries including manufacturing, healthcare, food, and nonprofit organizations. His client list includes major global corporations and industrial leaders such as American Axle, Berger Health Systems, Bosch, Caterpillar, Daewoo, Delphi Automotive Systems, Fiat-Chrysler Automotive, Ford, General Motors, Hyundai Motor Company, ITT Industries, Johns Manville, Kaplan Professional, Kia Motors, Leader Dogs for the Blind, Loral Space Systems, Make It Right Foundation, Mark IV Automotive, Procter & Gamble, State of Michigan, Thomson Multimedia, TRW, Volkswagen, Xerox, and more. Under Subir's leadership, ASI Consulting Group has helped hundreds of clients around the world save billions of dollars in recovered productivity and increased revenues.

Subir is the author of 14 books, including the international bestseller The Power of Six Sigma (Dearborn Trade, 2001), which has sold more than a million copies worldwide and been translated into more than 20 languages. Design for Six Sigma (Kaplan Professional, 2002) was the first book to popularize the “DFSS” concept. With quality pioneer Dr. Genichi Taguchi, Subir co-authored two technical bestsellers Robust Engineering (McGraw Hill, 1999) and Taguchi's Quality Engineering Handbook (Wiley, 2005).

His book, the critically acclaimed The Ice Cream Maker (Random House Doubleday, 2005) introduced LEO® (Listen, Enrich, Optimize), a flexible management strategy that brings the concept of quality to every member of an organization. The book was formally recognized and distributed to every member of the 109th Congress. The LEO process continues to be implemented in many organizations. His most recent book, The Power of LEO (McGraw-Hill, 2011) was an Inc. Magazine bestseller. A follow-up to The Ice Cream Maker, the book shows organizations how the LEO methodology can be integrated into a complete quality management system.

London, UK based Thinkers50 named Subir as one of the “50 Most Influential Management Thinkers in the World” in 2011, 2013 and 2015. Subir is a recipient of the Society of Manufacturing Engineers' Gold Medal, the Society of Automotive Engineers' (SAE) Henry Ford II Distinguished Award for excellence in Automotive Engineering and the American Society of Quality's first Philip Crosby Medal for authoring the most influential book on Quality. The US Department of Homeland Security presented the “Outstanding American by Choice Award” to Subir for his contributions to the field of quality and management.

In 2014, the University of California at Berkeley established the Subir & Malini Chowdhury Center for Bangladesh Studies. The Center will award graduate fellowships, scholarships, and research grants that focus on ways to improve the quality of life for the people of Bangladesh.

Each year the Subir Chowdhury Fellowship on Quality and Economics is awarded by both Harvard University and London School of Economics and Political Science to a doctoral student to research and study the impact of quality in the economic advancement of a nation. The SAE International established the “Subir Chowdhury Medal of Quality Leadership,” an annual award that recognizes those individuals who promote innovation and expand the impact of quality in mobility engineering, design and manufacturing.

Subir received his undergraduate degree in Aeronautical Engineering from the Indian Institute of Technology (IIT), Kharagpur, India and his graduate degree in Industrial Management from Central Michigan University, Mt. Pleasant, Michigan. He has received Distinguished Alumnus Awards from both universities, as well as an honorary doctorate of engineering from the Michigan Technological University.

Subir lives with his wife, Malini and two children, Anandi and Anish, in Los Angeles, California.

Shin Taguchi is Chief Technical Officer (CTO) for ASI Consulting Group, LLC. He is a Master Black Belt in Six Sigma and Design for Six Sigma (DFSS) and was one of the world authorities in developing the DFSS program at ASI-CG, an internationally recognized training and consulting organization, dedicated to improving the competitive position of industries. He is the son of Dr. Genichi Taguchi, developer of new engineering approaches for robust technology that have saved American industry billions of dollars.

Over the last thirty years, Shin has trained more than 60 000 engineers around the world in quality engineering, product/process optimization, and robust design techniques, Mahalanobis-Taguchi System, known as Taguchi Methods™. Some of the many clients he has helped to make products and processes Robust include: Ford Motor Company, General Motors, Delphi Automotive Systems, Fiat-Chrysler Automotive, ITT, Kodak, Lexmark, Goodyear Tire & Rubber, General Electric, Miller Brewing, The Budd Company, Westinghouse, NASA, Texas Instruments, Xerox, Hyundai Motor Company, TRW and many others. In 1996, Shin developed and started to teach a Taguchi Certification Course. Over 360 people have graduated to date from this ongoing 16-day master certification course.

Shin is a Fellow of the Royal Statistical Society in London, and is a member of the Institute of Industrial Engineering (IIE) and the American Society for Quality (ASQ); Shin is a member of the Quality Control Research Group of the Japanese Standards Association (JSA) and Quality Engineering Society of Japan. He is an editor of the Quality Engineering Forum Technical Journal and was awarded the Craig Award for the best technical paper presented at the annual conference of the ASQ. Shin has been featured in the media through a number of national and international forums, including Fortune Magazine and Actionline (a publication of AIAG). Shin co-authored Robust Engineering, published by McGraw Hill in 1999. He has given presentations and workshops at numerous conferences, including ASQ, ASME, SME, SAE, and IIE. He is also a Master Black Belt for Design for Six Sigma (DFSS).

Shin holds a Bachelor of Science degree in Industrial Engineering and Statistics from the University of Michigan and trains and consults with many major corporations worldwide.

Shin lives with his wife, Junko and three children, Hana, Yumi and Miki, in West Bloomfield, Michigan.