Modern Approaches to Manufacturing Improvement

The Shingo System

Alan Robinson

• Publisher: Routledge
• Year: 2017
• Topic: Business
• eBook ISBN:
  9781351430630
• Subtopic: Operations
• Index: Business

Here's the quickest and most inexpensive way to learn about the pioneering work of Shigeo Shingo, co-creator (with Taiichi Ohno) of just-in-time. It's an introductory book containing excerpts of five of his classic books as well as an excellent introduction by Professor Robinson.

1

Editor’s Introduction

Shigeo Shingo’s Contributions to Manufacturing

So much of what we call management consists of making it difficult for people to work.

Peter Drucker

Shigeo Shingo has made substantial contributions to the rapid growth and success of Japan’s manufacturing sector since the end of World War II. Although he is not yet as well known in the West as other industrial figures such as Akio Morita (co-founder of Sony), Soichiro Honda (founder of Honda), Konosuke Matsushita (founder of Matsushita Electric), and certain members of the Toyoda family (founders of Toyota Motor Corporation), his influence on the history and techniques of manufacturing is significantly greater. Not only did he co-develop (withTaiichi Ohno ofToyota) the Toyota production system (better known as the first Just-in-Time production control system), he invented the SMED (Single-Minute Exchange of Die) system for setup time reduction and the poka-yoke concept of “mistake-proof’ or zero-defect manufacturing. As a recognized leading expert on productivity improvement, he is known as “Dr. Improvement” in Japan.

It is well known that children deal better with an object if they know its name. For example, when young children are asked to draw objects on a tray presented to them, they tend to draw only the objects they can identify by name. The principle seems to extend to adults. Shigeo Shingo has trained himself over his long career to see things that others do not or cannot see. He has applied his rare intelligence not only to the solution of problems, but to building methodologies, and assigning “words” to his own fresh theories so that the rest of us can make them part of our vocabulary, thus, part of our cognitive repertoire.

Background

The concept of Just-in-Time (JIT) originated with Kiichiro Toyoda, the first president of Toyota Motor Corporation, which was created when Toyoda Automatic Looms spun off its truck division in 1936. When the company built its new plant in Koromo in 1938, Toyoda also planned that it should have a new production system: what he called “Just-in-Time.” Eiji Toyoda, now president of Toyota Motor Corporation, wrote of this in his autobiography:

We were then using a lot production system, but Kiichiro’s idea was to switch over entirely to a flow-type production system. He reasoned that this would eliminate large stocks of materials and parts, doing away with the need for warehouses. Cutting back running stock would also reduce capital outflow. If, once this production system got under way, we were able to sell our finished product before payments were due on our materials and parts, we would no longer have any need for operating capital.

What Kiichiro had in mind was to produce the needed quantity of the required parts each day. To make this a reality, every single step of the operation, like it or not, had to be converted over to his flow production concept. Kiichiro referred to this as the “just-in-time” concept.¹

When war broke out between Japan and the United States, it became impossible to use the new JIT system at Toyota. Each month Toyota was ordered by the military to make a certain number of trucks, and was allotted materials by the Japanese government with which to work. The problem faced by the infant JIT system was that the orders and the allotments came from two different agencies and were therefore uncoordinated.

After the war, when Kiichiro Toyoda was no longer president of Toyota, Taiichi Ohno, a Toyota plant manager and vice president, revived the idea of Just-in-Time, and over the course of the next two decades, championed its development at Toyota. Taiichi Ohno used an interesting analogy to communicate his philosophy of what was named “the Toyota production system.” He likened the company to a ship which floats on the “water” of inventory. This water covers up “rocks,” each of which represent production problems, such as quality problems, vendor problems, process imbalances, delays, and unreliable machines that break down often. If the water level is high, then the ship will not hit the rocks, that is, no problems will appear. If the water level is lowered, then rocks appear and the ship will hit them. Since water (at least for the purposes of this analogy) is expensive, to lower costs the company should continuously lower the water until a rock appears, at which point water should be added back into the system while all concerned study how to remove, or pare down, the rock. Gradually, the engine of production is “leaned out” until it runs smoothly and with minimal waste.

Dr. Shingo made vital contributions to the paring down of the two most significant and difficult rocks. First was the rock of the high cost and long times needed for setup operations (to reconfigure or “set up” a machine to do a new task). Second was the rock of quality problems and defects.

The Benefits of the SMED System

Dr. Shingo’s SMED system permits many kinds of setup operations to be performed in minutes rather than hours. When several workers and many hours (often more than 20) are required to set up a machine, it makes good sense to amortize the high cost of setup by producing in large batches. But if, as Dr. Shingo points out, the time and resources needed for setup operations can be dramatically reduced (and, possibly, even made insignificant), the rationale for lengthy production runs is largely removed. Low setup times and costs are key requirements of any system that is aimed at minimal inventory and low overhead. They allow for the profitable low-volume production of many products, and make it possible for high-volume production to be achieved economically through many short production runs. In addition to lowering work-in-process inventory, smaller batch sizes reduce lead time and process variability, because they cause products to flow more uniformly, rather than in intense and long spurts. With smaller batch sizes flowing uniformly, scheduling and planning overhead decreases automatically — as do problems of materials handling — since the product flows more evenly and in smaller and therefore more portable quantities. Also, defects are quickly spotted and removed.

In the readings on SMED contained in the third and final section of this book, Dr. Shingo in each case explains clearly, and in an easily implementable way, how to reduce setup times drastically in many situations, and what the consequences of these reduced times will be. The average reduction in setup time reported in a 1986 survey of 120 companies applying the SMED system was ninety-eight percent.

Poka-Yoke: Assuring Quality at the Source

The other important “rock” addressed by Dr. Shingo is that of poor quality. The concept of poka-yoke [pronounced POka YOkay] is at the heart of zero-defect manufacturing (also known as Zero Quality Control). A poka-yoke is a device or practice that guarantees that an error, once its cause is known, will never recur. As you read Dr. Shingo’s exposition of poka-yoke, in which he accurately observes that “money and resourcefulness offset one another,” you will see that poka-yoke devices are characterized by three attributes: cleverness, simplicity, and inexpensiveness. I came across a good example of poka-yoke while on a team researching a case study on the DCM-Toyota Ltd. truck plant in the northern Indian town of Surajpur. In order to prevent workers from sometimes forgetting to tighten certain critical bolts on the vehicle, wrenches were kept in a bucket of brightly colored paint. When a bolt had been missed, it lacked the noticeable splash of color, thus reminding the worker that it should be tightened.

Many companies still use methods of monitoring or controlling quality (such as Statistical Quality Control), even when it is possible for them to use simple tools like poka-yoke that assure quality. The distinction between control and assurance is one that Dr. Shingo will make clear in the readings on Zero Quality Control in Section Two. As you will see, Dr. Shingo is not the world’s most avid fan of Statistical Quality Control.

A System of Continuous Improvement

The JIT system constantly strives for improvements in productivity. Waste is exposed by the persistent lowering of inventory, and is then eliminated. Are the resulting improvements worth the time and trouble? Usually they are.

In Kaisha: The Japanese Corporation, James Abegglen and George Stalk, of the Boston Consulting Group’s Tokyo office, estimate that labor productivity is almost three times higher in a factory with JIT than in an equivalent one without it. My students were confronted rather starkly with the consequences of these increased levels of productivity during a recent field trip in the Boston area.

The plant we visited had a mock assembly line, which had been set up that day to run first in the classical way, and then in the JIT way. The students acted as workers, inspectors, and managers. After twenty minutes of hard work in the classical format, the line was switched over to JIT. Half of the students were asked to step back from the line, while the other half rotated into new jobs so that the comparison would be fair. This new and leaner configuration produced twice as many finished goods with half the number of workers as had the classical system. Not surprisingly, the question then arose: “In the real-world, what would have happened to the workers who were not needed any more?”

The answer, of course, is that they would be reassigned to work that is more productive. Ideally, that is what should happen, but a traditional obstacle to productivity improvement (certainly a favorite area for labor-management dispute in both Japan and the United States) has been precisely the tendency for companies to cash-in on such improvements by firing workers. A good way to ensure that improvement will never happen, of course, is to lay people off for improving.

Differences in Japanese and Western Approaches to Production Management

I am asked often by students to articulate the essential differences between modern Japanese and Western thought and practice in production management. I believe that there are four:

1. Japanese Companies Are More Active About Process Improvement and Simplification Than Their Western Counterparts

A colleague of mine was recently taken on a plant tour of a well known automobile company in England. The tour was being conducted by a vice president of the company. This man was most anxious to please a Japanese corporate vice president who was also on tour — to examine the possibility of a sale of all or part of the British company to the Japanese company. As the tour progressed through the plant, the Japanese visitor was politely complimentary until the guide turned to him and asked if he would like to see the plant’s fully automated warehouse, where all the storage and retrieval was done by robots under the control of a central computer. With a wave of his hand the Toyota man indicated that this would not be necessary. In fact, he was not interested. Under Toyota management the warehouse is not needed.

During his visit to the School of Management at the University of Massachusetts, Dr. Shingo told me a similar story. He was touring an American plant under the guidance of an overbearing plant manager who marched him into a fancy automated warehouse and asked him patronizingly, “Do you have such warehouses in Japan?” Dr. Shingo replied, “No, we are too poor to afford such nice warehouses; we must use our brains.”

During a recent tour of a catalog-merchandise warehouse that covered forty-five acres, my students and I were impressed with the amounts of goods in storage, the extent of the belts and conveyors and their high operating speeds and sorting rates. In general, we were awed by the level of automation and technology. Afterwards, during the panel discussion with plant staff, one of the operations managers alluded to the company’s projected high-growth rate of the warehousing division for the next ten years and suggested to my students that it might therefore be an excellent place for them to work after graduation. To my great pleasure a student then asked if the company would have any warehouses at all in ten years, given the unmistakable trend toward lower inventories and short lead times (when a shirt ordered over the telephone would be manufactured and mailed within forty-eight hours, instead of retrieved and mailed in the same time frame). This young man’s question somewhat dampened the manager’s recruiting pitch.

In his introduction, Dr. Shingo explains the difference between processes and operations. Unfortunately, this difference is widely unrecognized. But it lies at the heart of the simplification and improvement of production systems and accounts for much of the Japanese success in production over the last twenty years. A process is what the product experiences; it consists of a collection of operations. Since operations are what machines and workers perform, it can be very easy to lose sight of the process amidst all the more visible operations. When trying to improve, it is important to keep the distinction between operations and processes clear:

• An automated warehouse is an operations improvement: it speeds up and makes the operation of storing items more efficient. Eliminating all or part of the need for the warehouse by tuning production better to the market is a process improvement.

• Conveyor belts, cranes, and forklift trucks are operations improvements: they speed and aid the act of transporting goods. Elimination of the need for transport in the first place is a process improvement.

• Finding faster and easier ways to remove glue, paint, oil, burrs and other undesirables from products are operations improvements; finding ways not to put them there in the first place is a process improvement.

Japanese companies have tended to be more process-oriented than their Western counterparts, who have tended to focus instead on operations. It is precisely this difference that prompted the following observation from Robert Hayes and Kim Clark in an article written in 1985:

This American mentality has also kept us from exploring the impact of changing the basic structure of problems. If one is confronted with a highly complex factory environment—lots of production stages, lots of products, lots of flow patterns, lots of inventory locations, and so forth—one can deal with it in one of two ways. One can either attempt to develop a highly sophisticated (and usually computerized) information and control system to manage all this complexity, or one can set about reducing the complexity…. We have spent over a decade and millions of dollars developing elegant Materials Requirements Planning systems, while the Japanese were spending their time simplifying their factories to the point where materials control can be managed manually with a handful of kanban cards.²

2. The Japanese Have a More Enlightened Attitude Towards Employees

New United Motor Manufacturing Incorporated (NUMMI) of Fremont, California, is a joint venture between Toyota Motor Corporation an...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Publisher’s Foreword
• 1 Editor’s Introduction: Shigeo Shingo’s Contributions to Manufacturing
• 2 Author’s Introduction: Fundamental Flaws in European and American Production Philosophies
• Section One: Improvement
• Section Two: Zero Quality Control Source Inspection and the Poka-Yoke System
• Section Three: A Revolution in Manufacturing: The SMED System
• Index