"Mistake Proofing for Operators the ZQC system"
The system for ensuring you mistake proof your processes.
The Zero Quality Control System (ZQC) is a mistake proofing approach that prevents defects by monitoring processing conditions at the source and correcting errors that cause defects. Since it is human nature to make mistakes, ZQC does not blame people for errors, but instead finds ways to keep errors from becoming defects. In this breakthrough approach, mistake proofing devices called poka-yoke are used to check and give feedback about each product or operation in the process, not just a sample. This book introduces operators and assembly workers to the basic methodology of ZQC in an easy-to-read format that covers all aspects of this important manufacturing improvement strategy
Key learning features in Mistake Proofing for Operators: •a universal reading level •chapter overviews and summaries •margin icons that highlight key learning points •real-life examples to reinforce new ideas •reflection questions throughout that help readers apply the concepts•drawings, illustrations, and photographs
Mistake-Proofing for Operators includes the instructional features that are the signature of the Shopfloor Series. In this series Productivity Press has taken the lead in adult education by teaming with instructional designers to develop complete programs for frontline learning. The goal: to place powerful and proven improvement tools such as ZQC and mistake-proofing in the hands of your company's entire workforce.
Reviews
"This book, with its unique approach to learning, allows individual employees to
understand and apply the critical discipline of mistake-proofing to accomplish the goal of
zero defects."
- Gifford Brown, Plant Manager, Ford Motor Company, Cleveland Engine Plant 2
Winner of the 1996 Shingo Prize for Excellence in Manufacturing
"Mistake-Proofing for Operators presents Dr. Shingo's concept of ZQC in a format
for maximized breadth and depth of learning. The best poke-yoke opportunities are
discovered by production employees and can often be employed for only a few dollars but
only if employees have been trained to identify the opportunities. Any manager who truly
wishes to empower his or her employees to drive out defects should use this book for ZQC
training. the dramatic results of broad deployment, as we have discovered at United
Electric, go right to the bottom line."
- Bruce Hamilton, Vice President of Operations, United Electric Controls Company
Winner of the 1990 Shingo Prize for Excellence in Manufacturing
Mistake-Proofing for Operators is based on Zero Quality Control: Source Inspection and the
Poka-Yoke System by Shigeo Shingo
Preface
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The book is intended to give you powerful knowledge that you can use to
make your workplace more productive, and your job simpler and more satisfying. It's about
a way to manufacture or assemble products that have zero defects by catching and fixing
human mistakes and machine errors before they can cause defects. The mistake-proofing
approach you will learn about here is called Zero Quality Control (ZQC for short). Zero
Quality Control does not mean no quality control. On the contrary, it means quality
control that ensures zero defects, period-not just a reduction in defects.
ZQC has been used by leading Japanese companies for many years. It is one of the secrets
of low-inventory production, since no defects means no need for buffer inventory to
replace defective products. Today many leading Western manufacturers also use
mistake-proofing techniques. The ZQC system you will learn about here is the most
effective approach for mistake-proofing. It can eliminate wastes related to quality
defects-rework, scrap, and equipment downtime-and maintain the company's good reputation
with its customers. ZQC supports the company's competitiveness and makes production and
assembly work easier.
One of the great things about ZQC is that it focuses on correcting the conditions for
processing, not on blaming people for making mistakes. Shigeo Shingo, the developer of
ZQC, recognized that it is human nature to make mistakes or forget things. People should
not be punished for mistakes. Punishment only makes people feel bad-it doesn't eliminate
defects.
The solution Dr. Shingo came up with is explained in Mistake-Proofing for Operators.
Chapter 1 is like an "owner's manual" that tells you how to get the most out of
your reading by using margin assists, summaries, and other features to help you pull out
what you need to know. Chapter 2 describes the benefits of zero defects for companies and
employees. It tells about five different causes of defects, and introduces the idea of a
check before processing to catch unpredictable mistakes that could turn into defects.
Chapter 3 goes into more detail about this unusual idea of doing inspection before the
process instead of afterward. This kind of inspection before processing is called source
inspection, and this chapter compares it with other kinds of inspection like Statistical
Quality Control. This chapter goes on to introduce the other three "basics" of
ZQC: 100 percent inspection, quick feedback and action, and poka-yoke systems. 100 percent
inspection refers to the approach of checking every single unit of product, not just a
sampling. Quick feedback and action means a system for immediately informing someone that
there is a problem so they can do something about it before a defect is made.
In ZQC, the first three basics are carried out with poka-yoke systems. These systems use
simple, often inexpensive sensing devices to make sure the inspection happens every time.
They also give immediate feedback, such as stopping the equipment or giving a warning.
Limit switches and guide pins are two kinds of poka-yoke devices you will read about in
Chapter 4. Chapter 5 presents before and after examples of poka-yoke applications. Test
out your own ideas about mistake-proofing solutions by covering the bottom part of each
page while you think about the situation described at the top.
Chapter 6 wraps up with final reflections questions and resources to help you learn more
about mistake-proofing and ZQC.
Dr. Shingo often taught ZQC by telling stories about how people approach quality control.
Everyone can relate to the managers and employees he told about. Like most of us, they
were used to seeing things in a certain way. In Shingo's stories, you could just picture
the cartoon light bulb turning on when people realized there was a better way to do the
job. We hope this book captures some of the flavor of his thinking.
Mistake-Proofing for Operators was developed from Dr. Shingo's book, Zero Quality Control:
Source Inspection and the Poka-Yoke System, which was written for managers. When you get
right down to it, though, you-the frontline production and assembly associates-are the
people who know best what problems arise during production and have good ideas what to do
about them. Many of the mistake-proofing examples you will read about were developed by
shopfloor employees like you. In many cases operators and assembly associates participate
in installing mistake-proofing devices on existing equipment-or work with engineers and
designers to plan mistake-proofing systems into new equipment or processes. Since you have
the most to gain from applying ZQC, we have developed this book specifically to give you
the basics in a straightforward and interesting format. Once you understand these basics,
you can see how they might apply to your specific situation at work.
One of the most effective ways to use this book is to read and discuss it with other
employees in group learning sessions. We have deliberately planned the book so that it can
be used this way, with chunks of information that can be covered in a series of short
sessions or in one longer event. (Most chapters can be covered in a single session.) Each
chapter includes reflection questions to stimulate group discussion. A Learning Package is
also available, which includes a leader's guide, a copy of Dr. Shingo's book Zero Quality
Control, overhead transparencies to summarize major points, and color slides showing
examples of ZQC applications in different companies.
The Zero Quality Control approach is simple and universal. It works in companies all over
the world. Today, the basic principles of ZQC have been used to eliminate defects in all
types of manufacturing, assembly, and even service industries. We hope this book and
Learning Package will tell you what you need to know to be involved in a mistake-proofing
implementation and show you how ZQC can make your workplace a better place to spend your
time.
TABLE OF CONTENTS
MISTAKE-PROOFING FOR OPERATORS By: Productivity Press Development Team
ISBN: 1563271273
Contents
Preface ix
Chapter 1. Getting Started
Chapter Overview 1
Purpose of This Book 2
What This Book Is Based On 2
Two Ways to Use This Book 3
How to Get the Most Out of Your Reading 4
Becoming Familiar with This Book as a Whole 4
Becoming Familiar with Each Chapter 4
Using a Reading Strategy 6
Using the Margin Assists 7
Overview of the Contents 8
In Conclusion
Summary 10
Reflections 11
Chapter 2. Introduction to Zero Quality Control
Chapter Overview 13
What Is Zero Quality Control (ZQC)? 14
Why Focus on Zero Defects? 15
How ZQC Makes Your Work Easier 16
What Causes Defects? 17
Controlling Conditions so Defects Don't Happen 18
The Traditional Quality Improvement Cycle 18
Integrating Do and Check in the ZQC Approach 19
In Conclusion
Summary 20
Reflections 21
Chapter 3. Basic Elements of the ZQC System
Chapter Overview 23
The Four Elements of ZQC 24
Three Approaches to Product Inspection 25
Judgment Inspections Discover Defects 26
Informative Inspections Reduce Defects 27
Statistical Quality Control (SQC) 28
Successive Checks 28
Self-Checks 29
Source Inspection Keeps Errors from Becoming Defects 30
100 Percent Inspection Catches All Errors 31
A Short Feedback Loop Means Quicker Action on Problems 32
Poka-Yoke Systems Catch Errors We Might Have Missed 33
In Conclusion
Summary 34
Reflections 35
Chapter 4. Using Poka-Yoke Systems
Chapter Overview 37
About Poka-Yoke Systems 38
Poka-Yoke Systems in Source Inspection 38
Poka-Yoke Systems in Informative Inspections 38
How Poka-Yoke Systems Regulate the Process 39
Methods for Using Poka-Yoke Systems 40
Contact Methods 40
Fixed-Value Methods 42
Motion-Step Methods 42
Types of Sensing Devices 44
Physical Contact Sensing Devices 44
Energy Sensing Devices 46
Sensors That Detect Changes in Physical Conditions 50
Devices That Link to Poka-Yoke Sensors 51
In Conclusion
Summary 52
Reflections 54
Chapter 5. Examples of Poka-Yoke Applications
Chapter Overview 55
Learning from Examples of Poka-Yoke Applications 56
Poka-Yoke Systems Used in Source Inspection 57
Contact Method 58
Fixed-Value Method 63
Motion-Step Method 67
Poka-Yoke Systems Used in Informative Inspections 69
Contact Method 69
Fixed-Value Method 72
Motion-Step Method 73
In Conclusion
Summary 74
Reflections 74
Chapter 6. Reflections and Conclusions
Chapter Overview 75
Reflecting on What You've Learned 76
Applying What You've Learned 77
Possibilities for Applying What You've Learned 77
Your Personal Action Plan 77
Opportunities for Further Learning 78
Conclusions 78
Other Resources Related to ZQC and Mistake-Proofing 79
About the Authors 80
Mistake Proofing for
operators the ZQC system