Another view of six sigma

How many times of standard deviation is specification limit to the mean? If it is 2 times, then it is at 2sigma, if 3 times 3sigma, 4 times 4sigma, 5 times 5sigma.

If six standard deviations can be fitted between the mean and USL, then the process is at 6sigma. So, lesser the standard deviation, more number of them can be fit between those mean and USL thus pushing up the sigma level.

ISO Vs. Six Sigma

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TQM Vs. Six Sigma

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Green belt and black belt projects

Both green and black belt initiatives are process centric and driven towards process optimization. Green belt projects cover a single functional area, whereas black belt projects are cross-functional.

Green belt and black belt projects are taken up to achieve the process goals as demanded by business objectives. Identify the internal tasks where the variation can be controlled. Take them up as green belt projects…for example, the time lag between a “ready pizza” and its “pick up” can be focused and management techniques applied to optimize it.

USL/LSL & UCL/LCL

USL is the upper specification limit, while LSL is the lower specification limit. USL and LSL are dictated by / based on customer expectations. Some processes have only USL, some others have only LSL, and still others have both USL and LSL. (for example, the pizza example has only USL). Software processes have both USL and LSL.

Companies may have different kinds of processes for different customers, or may have the same processes for different customers. The types of processes to be followed are dictated by business demands, as customers have varying expectations.

UCL is the upper control limit, LCL the lower control limit. Control limits are three times the standard deviations (3Sigma always) on either side of the mean.