Research on "6 Sigma" Quality Management (2)

c) Development of quality improvement

In the 1920s, Walter A. Shewhart, a researcher at the Bell Institute, developed the concept of a "Control Chart" based on statistical methods. His colleague, W. Edwards Deming, developed this method in post-war Japan and set the direction for the quality requirements of Japanese product manufacturers. In the 1950s, AQL (Acceptable Quality Level), AOQ (Average Outgoing Quality Level), and LTPD (Lot Tolerance Percent Defective) methods were developed. In the 1960s, because the Soviet Union was more successful in space development than the United States, the US Department of Defense proposed management requirements for "zero defects." They think that if the workers can guarantee that the production can achieve zero defects, the quality will be guaranteed.

In 1987, there was an emergence of ISO 9000 affecting all walks of life. It is a good system for quality management. However, these document managements only produce bureaucratization. This system can only guarantee the existing quality requirements, but it does not contribute to the continuous improvement of products.

In fact, in the 1980s and 1990s, Total Quality Management was also advocated. The method was to continuously improve quality and achieve a dream of zero defects. In Western countries, several quality management experts have had an extremely significant impact on international quality management. Among them are W. Edward Deming, Joseph H. Juran, Philip Crosby, etc. . Over the past decade or so, major companies in Western countries have considered the works of these masters and even hired them as consultants if they consider implementing a quality improvement plan. Especially in Japan, Deming and Juran have an exceptionally high status. The “Deming Award” (Deming Quality Award) under the name of Deming is still the highest honor of quality management in Japan.

However, at the time, the quality-cost curve theory put forward by Juran had been challenged in the 1980s. (See Figure 1)

He thought that when the quality was improved to a certain degree, even if the resources were greatly increased, the effect was not obvious. So the so-called zero defect is an unrealistic ideal. It was also popular when the quality reached a certain range. The theory is exactly the same as that of the Longmen. If the football hits the square, one point is scored (see Figures 2 and 3).

Thanks to advances in science and technology, various types of equipment can replace manpower and play an opportunity to prevent the appearance of defective products. A breakthrough quality cost curve emerged (see Figure 4).

If we are to prevent and test the increase of resources, the "zero defect" ideal can be achieved. In addition, Taguchi, a Japanese quality management expert at that time, overthrew the quality requirements theory of the Longmen, he proposed that the product quality should be at a certain point of the midline position, higher or lower than this point represents the cost increase (check, test, rework, etc. ), and represents increased dissatisfaction with guests (see Figure 3). Other quality management experts such as Ishikawa, Kaizen, etc. all share the same idea.

In terms of product management, quality management masters at the time thought that they could achieve "all-round quality management" through Quality Circles, quality control and assurance, and staff training and participation at all levels. After more than a decade of hard work, apart from the outstanding Xerox example, its achievements are not significant. Just as Peter S. Pande puts forward his commentary on The Six Sigma Way, the concept of “Total Quality Management” lacks experienced management. Layers are pushed from top to bottom. The most deadly thing is the lack of clear goals to implement. They do not know how to achieve the goal. So many times they are misplaced, which leads to waste of resources.

The "all-round quality management" effort was not wasted. Motorola's "Six Sigma" quality management method proposed in 1987 was based on "total quality management" and was improved. Their Continuous Improvement, Seven-Step Method and Total Customer Satisfaction are all based on the concept of Total Quality Management (TQM). Motorola added "6 Sigma" product requirements to its slogan and used Black Belt's experienced management personnel to implement it. Motorola and General Electric are typical examples of success, and have also inspired other companies to learn. At the same time, many books and articles about "6 Sigma" appeared on the Internet. In addition, many quality consulting companies have promoted and provided "6 Sigma" management services.

However, the success of "6 Sigma" has also attracted many enemies, such as Thomas Pyzdek's "Motorola's Six Sigma Program (Note 2)" and Arthur M. Schneiderman's "Question: Whenis Six Sigmanot Six Sigma/Auswer:Whenit`s The Six Sigma Metric!! (note 3) questioned Motorola's statistical bias. According to their calculations, 6 Sigma represents only 2 defectives per 100 million products. Motorola's so-called 6 Sigma may only reach 4.5 Sigma. In essence, 6 Sigma does not represent the ultimate, 8 Sigma, 10 Sigma, 12 Sigma will continue to appear, according to Arthur M. Schneiderman's statement, when you reach 10 Sigma, using Motorola's method, and the correct method has a 1000-fold deviation. In addition, he questioned whether it was reasonable to determine the standards for quality requirements. In terms of production cost savings, it also represents an increase in the cost of product development and quality verification. Do they achieve a balance? He believes that the so-called "6 Sigma" is just a slogan and its center is "Total Quality Management."

In addition, Keki R. Bhote, who once worked as a senior consultant on the 6 Sigma project at Motorola, pointed out in his book “World Class Quality” that Motorola only provided baby-shaped “6 Sigma” (Baby Six Sigma-“. The Little Q"), he thought that he put forward "The Ultimate Sigma" "The Big Q" is the most effective. His proposed "Design of Experiments-DDE" and "The Ten Powerful Tool for the 21st Century" (Note 4) can best meet world-class quality management requirements.

d) Summary

On the road to quality improvement, various theories of learning doctrine can be described as diverse and flourishing. Their purpose is to “Continuous Improvement” to achieve “zero defect” levels. However, I hope readers do not be intimidated by the previous charts and calculation methods. As mentioned above, it only confirms the development of quality management and the definition of "6 Sigma." If we can achieve "zero defects" and "high-quality management," the calculation method is not comparable to what is provided in the previous article. I hope readers do not put the cart before the horse and spend time on the above statistics. To be honest, "6 Sigma" is just its slogan, and if it reaches "6 Sigma" or "zero defect" it is its spirit.

Although many consultant companies now use "6 Sigma" as their slogan to promote quality improvement services, their contents are varied and they are different from each other. They are completely different from the strict requirements of ISO 9000. All in all, they are based on Total Quality Management and combine the results of various management experts to develop their approach. For example, Peter S. Pande focuses on employee training, but Keki R. Bhote's book focuses on various statistical methods to monitor and identify products. This is an extreme example.

In any case, Motorola's "6 Sigma" uses the "Seven-Step Method" to succeed. To be honest, the "seven-step approach" is not a terribly new invention. It is only a method of Total Quality Management. Combined with Walter Shewhart's PDCA cycle “Plan-Do-Check-Act”, it becomes the goal of Continuous Improvement. Of course, Motorola’s “seven-step approach” The "team spirit", "top-to-bottom promotion method", "6 slogan slogan", and "quality check" will be added to succeed.

annotation

(1) "The Six Sigma Way" by Peter S. Pande, Robert P. Neuman Roland R. Cavanagh, MC Graw-Hill 2000 P43-49

(2) http://

(3) Same as above

(4) "World Class Quality" by Keki R. Bhote and Adi K. Bhote American Management Association, NewYork, 2000