Tolerance Design: A Handbook for Developing Optimal Specifications - Hardcover

Creveling, Clyde M.

Hardcover

ISBN 10: 0201634732 ISBN 13: 9780201634730

Publisher: Prentice Hall, 1996

Synopsis

Reviews the three initial phases of the productdevelopment process where tolerance development resides as the final cost-versus-quality balancing process. Covers all the basic analytical methods that exist in modern and traditional tolerancing techniques. Includes many examples and casestudies. DLC: Tolerance (Engineering)

About this title

About the Author

Clyde "Skip" Creveling is the president and founder of Product Development Systems & Solutions Inc. (PDSS) (http://www.pdssinc.com). Since PDSS' founding in 2002, Mr. Creveling has led Design for Six Sigma (DFSS) initiatives at Motorola, Carrier Corporation, StorageTek, Cummins Engine, BD, Mine Safety Appliances, Callaway Golf, and a major pharmaceutical company. Prior to founding PDSS, Mr. Creveling was an independent consultant, DFSS Product Manager, and DFSS Project Manager with Sigma Breakthrough Technologies Inc. (SBTI). During his tenure at SBTI he served as the DFSS Project Manager for 3M, Samsung SDI, Sequa Corp., and Universal Instruments.

Mr. Creveling was employed by Eastman Kodak for 17 years as a product development engineer within the Office Imaging Division. He also spent 18 months as a systems engineer for Heidelberg Digital as a member of the System Engineering Group. During his career at Kodak and Heidelberg he worked in R&D, Product Development/Design/System Engineering, and Manufacturing. Mr. Creveling has five U.S. patents.

He was an assistant professor at Rochester Institute of Technology for four years, developing and teaching undergraduate and graduate courses in mechanical engineering design, product and production system development, concept design, robust design, and tolerance design. Mr. Creveling is also a certified expert in Taguchi Methods.

He has lectured, conducted training, and consulted on product development process improvement, design for Six Sigma methods, technology development for Six Sigma, critical parameter management, robust design, and tolerance design theory and applications in numerous U.S, European, and Asian locations. He has been a guest lecturer at MIT, where he assisted in the development of a graduate course in robust design for the System Design and Management program.

Mr. Creveling is the author or coauthor of several books, including Six Sigma for Technical Processes, Six Sigma for Marketing Processes, Design for Six Sigma in Technology and Product Development, Tolerance Design, and Engineering Methods for Robust Product Design. He is the editorial advisor for Prentice Hall's Six Sigma for Innovation and Growth Series.

Mr. Creveling holds a B.S. in mechanical engineering technology and an M.S. from Rochester Institute of Technology.

From the Back Cover

Whether an engineer, designer, drafter, or technician, each member of the design engineering team has a valuable role to play in the development of product specifications. Tolerance Design recognizes this development process as the responsibility of the entire team and provides practical solutions that each team member can readily apply. The step-by-step details of analytical and experimental tolerance development methods are clearly explained, and as a result, you will be able to develop tolerances more economically.

The book is presented in four sections: Introductory topics to position the tolerance development process, Traditional Analytical and Computer-Aided Tolerance Development, Taguchi's Approach to Experimental Methods of Tolerance Development, as well as several actual industrial case studies illustrating the book's concepts. This book includes a major emphasis for Tolerance Design using Taguchi's Quality Loss Function in harmony with Motorola's famous methods for Six Sigma quality.

The blend of practical examples with substantive case studies provides a comprehensive process approach to tolerance development. Any company interested in properly developing tolerances for their manufacturing, assembly, or service communities will find this text to be a thorough and effective training resource and reference handbook. Students of design and engineering will find this book invaluable as they prepare to enter a competitive job market where practical design optimization skills are at a premium.

0201634732B04062001

From the Inside Flap

This is the first book in the history of engineering science to comprehensively address the analytical and experimental methods available for the development of tolerances. This indicates, on one hand, an unfortunate legacy of neglecting a very important engineering topic. On the other hand, it provides an opportunity for engineering practitioners, students, and educators to fill a void in their skill sets.

This book is written for a fairly diverse audience. It is intended to be used as a handbook for industrial applications as well as a course text in technology and engineering science programs at the college and university level. It is structured so that undergraduate technology and engineering students at the associate and baccalaureate levels can equally share in its informational value. The author views the tolerance development process as the responsibility of the design engineering team. This requires that the book be suitable for engineers, designer/drafters, and technicians. Each of these engineering team members has a valuable role to play in the development of product specifications. Tolerance Design contains detailed information for each of these team members.

This book is broad in scope. It reviews the three initial phases of the product-development process where tolerance development resides as the final cost-versus-quality balancing process. It explains, in detail, how tolerance design relates to concept design and parameter design. It also relates the tolerance design process to many other engineering and product development tools and tasks, including reliability growth activities. It covers all the basic analytical methods that exist in modern and traditional tolerancing techniques. It also rigorously covers the latest experimental methods that can be employed in the tolerance design process.

This text details step-by-step the analytical and experimental tolerance-development methods so the reader can more easily and properly develop tolerances. Many examples and case studies are used to convey the process of defining the right tolerances so they can be properly communicated to the manufacturing, assembly, and service communities. The text illustrates how to balance product cost and quality through the tolerance development process. Great emphasis is placed on how the engineering and manufacturing teams must work harmoniously and concurrently to develop optimal tolerances. Tolerance Design instills a philosophy that tolerance development is as much about cost optimization as it is about functional integrity.

This book has been heavily critiqued and scrutinized, on your behalf, by many of the top experts in the U.S. engineering, tolerance analysis, and tolerance communication communities. Much of their work has been included in this text. This was done to make the depth and breadth of the book rock solid. Since the book is the first of its kind, the author and publisher believed it had to be thoroughly evaluated, perhaps even more rigorously than usual, so that it could stand as a major contribution to engineering literature for many years to come. The book was "engineered" to meet your needs so you can meet your customer's needs.

The world is so competitive now that there is simply no way to keep our industries economically viable by using the same ad hoc engineering processes that have evolved over the past 50 years. With this in mind, a major focus in this text is given to the disciplined methods of quality engineering as defined by Dr. Genichi Taguchi. Engineering processes are now being taught in universities and applied in industries all over the United States. This book is very process oriented. It strives to teach discipline in the development of tolerances. In fact, you will have difficulty succeeding in tolerance optimization if the engineering processes that follow the tolerancing process are void of rigor and discipline. Taguchi's approach to product development provides an excellent engineering process context for our discussions.

The literature of off-line quality engineering is primarily focused on the parameter design process. There are numerous books and papers available on this topic, which is frequently referred to as robust design. The other two phases of off-line quality engineering--concept design and tolerance design--have received much less attention in published material. This is particularly true of tolerance design. Until now there has been no single book dedicated to the engineering process of designing tolerances using the quality-loss function. Furthermore, there has not been a single text on how to establish six-sigma process capability in the context of the quality-loss function and upper and lower specification limits that have been produced from the output from orthogonal array matrix experiments.

The question of why so little has been written on this practical subject is relatively easy to answer. Taguchi and his colleagues (myself included) have focused the majority of their writing, teaching, and consulting on developing robustness (insensitivity to sources of variability) as early as possible in the product development process. Consequently, the time and energy spent on promoting tolerance design is relatively small in comparison to the work done to promote the proper application of parameter design. Taguchi has written several interesting chapters that show the power of continuing to improve the quality of a product or process through the methods of tolerance design.

His unique contributions to tolerance literature include the application of orthogonal array matrix experiments--complete with stressful noises, ANOVA data decomposition, and the quality-loss function. He has provided a way to bring the design into production with a deliberate, balancing process to be sure both the customer and the corporation have the right quality and cost designed into the product. Dr. Taguchi's work is the basis for the third section of this book.

In the United States, the traditional approach to tolerancing has been primarily in the domain of designers and drafters as opposed to that of engineers. The engineering focus has been on defining the nominal set points at which the part or design functions correctly. The designers are frequently left to finish the job by defining the tolerances and then properly communicate them to the appropriate manufacturing personnel through drawings or specification documents. Tolerancing occurs naturally as a two-step process: the determination of the tolerance and the communication of the tolerance. In his book Total Quality Development, Don Clausing states:

"In parameter design, the best nominal (target) values are selected for the critical design parameters. In tolerance design, we select the economical precision around the nominal values in two steps: (1) selecting the right production precision, and (2) putting tolerance values on drawings . . . The intrinsically more important part of tolerance design is the selection of the best production precision. Strictly speaking, this has nothing to do with tolerances at all. Tolerances are the numbers that go on the drawing (pp. 249-250)."

The point is that regardless of whether the engineer or the designer or both establish the tolerances, the tolerances are critical to the successful manufacture and performance of the product over its intended life cycle. This book is all about the process of determining production tolerances. The process of communicating the tolerances is left to other fine texts, such as Geometrics III, by Lowell Foster.

This book includes a focus on the economics of the tolerance development process. As Taguchi points out in his book Taguchi on Robust Technology Development, the average loss N products will incur over time, T, is derived from the following general relationship:

This integral equation captures the central concept of how, on average, money (L(y)) is lost over time (T, total life and t, any point in time) as a measurable parameter (y) in a design deviates from its intended target value. It is clear that tolerances can play a significant role in the loss (Li(t, y)) of dollars incurred over the life (T) of the product. Thus, tolerance design can also have an impact on the economics associated with product reliability. This book is designed to make this particular concept of accounting for loss and improving reliability understandable to any technical person with a basic understanding of algebra. The reader should not be alarmed that an integral equation is used to communicate the nature of loss. It is my intention to make the loss function clear to all readers-not just those with a background in advanced mathematics. One of Taguchi's finest professional attributes is that he simplifies complex optimization processes to the point where practicing engineers and technical personnel can rapidly learn and apply them. I took great pains to continue this approach in this text. This is not a book to dazzle the theoreticians; rather, it is a practical guide to solving real engineering problems using a disciplined process. It is also meant as a follow-up text to

Edition details

• Publisher: Prentice Hall
• Publication date: 1996
• ISBN 10: 0201634732
• ISBN 13: 9780201634730
• Binding: Hardcover
• Language: English
• Edition number: 1
• Number of pages: 423