Verdict
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Control limits come from the process's own variation, not the tolerance: a process can sit inside spec while drifting badly, and a chart drawn against the specification never shows it. Capability is withheld while the process is out of control - Cpk on an unstable process describes a process that no longer exists.
Individuals and moving range Explain this chart
Click a reading to see the records behind it — or tab to one and press Enter. A dot on the lower chart is the gap between two readings and opens the later of them. The button opens the worst reading a rule fired on — rule 1 before rule 5 before the rest, the newest of those — and says which rule that is; the newest reading when none did.
Explain this chart opens the AI tab with the question already typed — about this characteristic, and about the point open beside it if one is. Read it, change it if it is not quite your question, then ask it. It reads; it changes nothing.
Why this reading is here
No reading is open. Click one on the chart beside this and every record this MES holds about it appears here: the gauge that took it and when it was last calibrated, the same characteristic by the other gauge in the hour either side, this station's process values over the ten minutes before it, what the machine was doing, and anything else that happened in that window. Nothing is modelled or guessed — every line is a record, and each block says how much of its window anybody was watching.
Rules that fired
A rule is judged when a reading is recorded, not when this page is opened,
and the first firing of an excursion raises a quality hold carrying the rule and its readings.
Later firings of the same excursion join that hold rather than opening another — what a plant
does next is a person's act, or a trigger the plant configures on spc.signal.
| Rule | Where | What it means | What it raised |
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