What is Manufacturing Quality Control?

Think of the amount of work required to transform a car from a random collection of assorted parts into the assembled entity that it is when it reaches the end of a production line. Cars don’t just spontaneously appear. There are a multitude of pieces that have to be put together in order to create … Continued

Organizing Charts in Engineering Mode: The Matrix Style

You have four charts and only one computer screen. How do you consolidate to a multiple chart view to compare data without having to thumb through individual charts? You might be tempted to resort to flashy, “Matrix”-style moves, but fear not, there is a simpler approach that is just as effective and doesn’t require stretching. … Continued

Modifying Control Chart Sensitivity

Control limits are typically set at +/- 3 standard deviations for the statistic being plotted. That‘s how traditional Shewhart control charts have been constructed for nearly a century. The result is a statistical tool that is simple and elegant, yet robust enough to tackle all manner of different situations and distributions of data. Control limits and their widths … Continued

3 “Nevers” of Control Limits, Part 2

Never allow control limits to be automatically recalculated I was hiking in the Smoky Mountains National Park with a colleague, and we happened upon fellow hikers. Being the friendly sorts that we are, we stopped to take a breather and chat with our new female friends. We enjoyed resting and speaking with the women until … Continued