What does a measurement falling within the control limits in a manufacturing process suggest?

When a measurement falls within the control limits in a manufacturing process, it indicates that the process is operating as expected and is stable. Control limits are statistical boundaries calculated based on the mean and variability of the process. Therefore, if the measurements consistently fall within these limits, it suggests that the process is in control and functioning properly.

This signals that the variations seen in the output are normal, inherent fluctuations, rather than signs of systemic issues or problems needing corrections. While it does not guarantee that every single unit manufactured is perfect, it implies a high level of consistency and reliability in production, which typically leads to the majority of products being acceptable. The presence of control within the process means that any variations observed are due to common cause variation rather than special cause variation, which can require adjustments or corrective action.