Multiple Locations Charts

Section 6 Charts for Multiple Locations

Lesson S06-01

Text: Section 6 pages 1 – 7

Duration: 17 minutes

Introduction to Multiple Locations Charts

There are many instances where subgroups of size two or more are most convenient, but there is a possible violation of rational sampling. For example, a workstation machines several parts per cycle, so that the parts in the subgroup were machined in the same cycle, but at different locations on the workstation.

Another instance might be that there are multiple production lines performing the same task. Another example is destructive testing, where multiple measurements are often taken on a single part (to avoid destruction of multiple parts), but the part might not be homogeneous.

In any case, traditional SPC does not handle the situations described above unless the locations are essentially the same.

A Possible Solution

Still a Problem

An Example of the Problem

A Plot to Detect the Problem