This figure is based on the tolerance in the height of a stack of discs. The 3.4 dpmo is based on a 'shift' of ± 1.5 sigma explained by Mikel Harry. Processes that operate with 'six sigma quality' over the short term are assumed to produce long-term defect levels below 3.4 defects per million opportunities (DPMO). Originally, it referred to the ability of manufacturing processes to produce a very high proportion of output within specification. The term Six Sigma comes from statistics, specifically from the field of statistical quality control, which evaluates process capability. Even if the mean were to move right or left by 1.5 standard deviations (also known as a 1.5 sigma shift, colored red and blue), there is still a safety cushion. Normal distribution means that values far away from the mean are extremely unlikely-approximately 1 in a billion too low, and the same too high. The upper and lower specification limits (USL and LSL) are at a distance of 6σ from the mean. The greater the standard deviation, the larger the spread of values for the green curve, μ = 0 and σ = 1. At 0, μ ( mu) marks the mean, with the horizontal axis showing distance from the mean, denoted in units of standard deviation (represented as σ or sigma). Other standards have been created mostly by universities or companies with Six Sigma first-party certification programs.Įtymology Normal distribution underlies the statistical assumptions of Six Sigma. In 2011, the International Organization for Standardization (ISO) published the first standard 'ISO 13053:2011' defining a Six Sigma process. The Lean Six Sigma methodology views lean manufacturing, which addresses process flow and waste issues, and Six Sigma, with its focus on variation and design, as complementary disciplines aimed at promoting 'business and operational excellence'. In recent years, some practitioners have combined Six Sigma ideas with lean manufacturing to create a methodology named Lean Six Sigma. By the late 1990s, about two thirds of the Fortune 500 organizations had begun Six Sigma initiatives with the aim of reducing costs and improving quality.

In 1998 GE announced $350 million in cost savings thanks to Six Sigma, which was an important factor in the spread of Six Sigma (this figure later grew to more than $1 billion). As GE's CEO, in 1995 Jack Welch made it central to his business strategy. Honeywell and General Electric were also early adopters of Six Sigma. In 2005 Motorola attributed over $17 billion in savings to Six Sigma. Service Mark 1,647,704) on December 28, 1993, it registered Six Sigma as a trademark. It registered Six Sigma as a service mark on J( U.S.

Motorola pioneered Six Sigma, setting a 'six sigma' goal for its manufacturing business. The term Six Sigma originates from statistical quality control, a reference to the fraction of a normal curve that lies within six standard deviations of the mean, used to represent a defect rate. Each Six Sigma project follows a defined methodology and has specific value targets, such as reducing pollution or increasing customer satisfaction. This is done by using empirical and statistical quality management methods and by hiring people who serve as Six Sigma experts. Six Sigma strategies seek to improve manufacturing quality by identifying and removing the causes of defects and minimizing variability in manufacturing and business processes. It was introduced by American engineer Bill Smith while working at Motorola in 1986.

Six Sigma ( 6σ) is a set of techniques and tools for process improvement.

Six sigma success story