The second “pillar” of the Toyota Production System is Jidoka, a system for detecting defects and abnormal conditions in production, automatically stopping a line so that quality issues can be quickly addressed. In even the leanest manufacturing plants, some quality issues arise that are difficult to identify and correct. Six Sigma is especially effective at identifying the root cause of quality problems – and eliminating defects by reducing variation in manufacturing processes.
Despite the use of the term today, Six Sigma is actually a numerical measurement of quality. To achieve Six Sigma, precisely 99.99966% of what you do must be without defects. From a manufacturing standpoint, that means just 3.4 defects per million products or parts made. Surprisingly, manufacturing 99% without defects means you’ll have 10,000 defects per million – and at 95% that number jumps to 50,000 defects. See a timeline of the evolution |
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The quality tools and
techniques that were named “Six Sigma” in 1986 by Motorola (actually by a Motorola engineer named Bill Smith)
are not new. They were developed over the past 50 or more years, through the work of quality experts such as Deming, Juran and others.
