A key feature of Six Sigma is the integrated use of design of experiments and robust design of product and process. Experiments are an important part of this; they...
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06Mar
SPC vs. Knowledge
Article Revised: March 26, 2019 Have you ever asked yourself just what control limits actually measure? Oh sure, there are the standard statistical answers: central tendency, process dispersion, capability and...
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06Mar
Small Samples
What is “Small”? Not enough data. We’ve all been there before. It may be that the production rate is too low. (I’ve worked with processes where one unit per...
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06Mar
Six Sigma, Data Mining and Dead Customer Accounts
Article Revised: March 26, 2019 In the February issue of Quality Digest, Joseph M. Juran pointed out that quality needs to “scale up” if it is to remain a viable...
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06Mar
Non-Normal Distributions in the Real World
One day, early in my quality career, I was approached by my friend Wayne, the manager of our galvanizing plant. ‘Tom,” he began, “I’ve really been pushing quality in...
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06Mar
How Do I Compute sigma? Let Me Count the Ways.
With SPC work, we normally try to analyze a process distribution’s shape, central tendency and spread. We usually measure this last item by computing an estimate of the process...
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06Mar
Applying Virtual DOE in the Real World
In last month’s column I presented a method for conducting virtual design of experiments (VDOE) using artificial neural networks and data mining. This month I will present a manufacturing...
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06Mar
Selecting Winning Project Portfolios
Article Revised: March 26, 2019 In a previous column I discussed how Six Sigma projects should be selected using the theory of constraints (TOC). After attempting to do so, most...
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06Mar
DMAIC and project plans
Article Revised: April 26, 2019 Six Sigma’s magic doesn’t lie in statistical or high-tech razzle-dazzle. Six Sigma relies on tried-and-true methods that have been around for decades. In fact, Six...
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06Mar
Divide and Conquer
Article Revised: March 26, 2019 A typical Six Sigma project adds between $145,000 and $250,000 to the bottom line. These numbers provide useful guidelines to the Black Belt for breaking...
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