Lean Six Sigma Using SigmaXL and Minitab

Book Preface

Business production methodologies have never stopped improving sinceFrederick W. Taylor, the inventor of scientifi c management, devised techniques for factory management and time and motion studies. Eli Whitney created the methods for interchangeable parts and Henry Ford developed the modern assembly lines used in mass production today. These inventions were the precursors of the modern day quality and productivity improvement methodologies.

Over the past three decades, many managerial methodologies aimed at improving production processes have been introduced to businesses throughout the world. Some have resisted skepticism and have prevailed and are still being used, while others, such as the total quality management (TQM) or company wide quality control (CWQC), have been deemed to be nothing but fads and have disappeared almost immediately after they appeared. In fact, all the process improvement strategies (Six Sigma, TQM, CWQC, Lean, TOC, etc.) have the same underlying philosophy; they are all geared toward customer satisfaction and insist on the necessity for all sections of a company to cooperate in order to improve all aspects of its operations. They all insist on producing high-quality products at the lowest possible cost through a reduction of waste and continuous improvement.

Some companies have deployed TQM and failed because the deployment was conducted badly, their employees were poorly trained, or the areas they insisted on improving were areas that did not require improvement because their improvement would not have had a positive impact on the overall performance of the business. This costs money and does not generate any signifi cant return on investment.

In most cases, TQM did not fail because it was in itself a bad methodology or that its application was conducive to poor performance and failure. In fact, the name of the methodology that a company uses to improve its processes should not be the most germane aspect of its management strategy. Currently, the most widespread methodologies used in management are Six Sigma and Lean, also known as the Toyota Production System (TPS).

Indeed, most of the tools that were used by TQM have been refi ned and are still being used in Six Sigma. Six Sigma and Lean have withstood skepticism largely because of the success some major corporations have seen as a direct result of their application. A careful observation of those corporations would reveal that Six Sigma and Lean are not partially used and, in most cases, they have become a culture, a way of managing for those companies instead of auxiliary instruments temporarily used to solve a circumstantial problem.

Six Sigma is a data-driven business strategy that seeks to streamline production processes to constantly generate quasi-perfect products and services in order to achieve breakthrough return on investment. One of the pillars of Six Sigma is the pursuit of the reduction of production process variation to an infi nitesimal level.

Lean manufacturing or TPS is a management methodology originated in Japan and more often associated with Toyota Motor Company; it was introduced to the American public by James Womack and Daniel T. Jones in the 1990s. It is about doing things right the fi rst time and every time at a steady pace. It is also about reducing cycle time and inventory by eliminating waste. The underlying foundation of Lean manufacturing is the organizational strategy that constantly seeks a continuous improvement through the identifi cation of the non-valueadded activities (Muda) and their elimination along with the reduction of the time it takes to perform the value-added tasks.

Most companies use these two methodologies simultaneously for process improvement because, taken in isolation, each of these methodologies can yield good results. However, when they are combined, the probability for success is even greater.

This book is written as a practical introduction to Lean Six Sigma project execution and follows the DMAIC (defi ne, measure, analyze, improve, and control) roadmap. It is written in such a way that it can be used as a training text for beginners and a reference for seasoned practitioners. Six Sigma is, by defi nition, analytical and profoundly rooted in statistical analysis. Therefore, ample statistical theory and development are provided to support the analyses. Both a theoretical analysis and the two most widely used statistical software suites, SigmaXL and Minitab, are used throughout the examples to help the reader better understand how to execute a Lean Six Sigma project.

The book is based on years of teaching the Lean and Six Sigma methodologies to a wide variety of audiences from different industries. We hope that the content of the book will be helpful in furthering the understanding of Lean Six Sigma project execution.