Control Limits

Called "the Voice of the Process," control limits are calculated from collected data, showing how the process is performing. After collecting a sufficient number of subgroups, you should set the control limits, which stores their values in Enact.

Enact automatically updates control limits every 10 minutes, which means there will be a slight delay before you see recent changes.

In-Control

When a process is in-control, it is stable and within the current control limits. This does not mean that the process is automatically within the specification limits. A process might be in-control but outside of specification limits, meaning the parts being manufactured are consistently bad.

Out-Of-Control

When a process is out-of-control, it is unpredictable, which means it is not behaving the way it has in the past. This does not mean that the process is automatically outside the specification limits. A process might be out-of-control but in of specification limits, meaning the parts might be acceptable, but there is no way of ensuring they will remain that way.

Any change in the control limits might be from a decrease or increase in variation, but it has nothing to do with the specification limits. Control limits have no relationship to the specification limits, and must never be calculated from specification limits.