The loop
Manufacture, measure, analyse, calculate, validate, compensate, verify. In machining, the measurement may come from an in-machine probe, a gauge or a CMM, and the compensation is usually a tool offset or a work offset.
Do not chase noise
Measurements contain random variation. If every deviation triggers a full correction, the loop adds variation rather than removing it. Practical loops use a deadband, average several measurements, apply only a fraction of the estimated error, and look for real trends before acting.
Limits and approval
Because the loop changes how a machine runs, it needs hard safeguards: absolute bounds for each parameter, a maximum single step, a maximum cumulative change over time, and checks that the machine is ready and the data is fresh. Corrections beyond those limits should wait for a person with the authority to approve them.
Verification
Every executed correction should be followed by measurement to confirm the intended effect. If it did not work, the system should stop correcting and escalate rather than keep adjusting.
Where AI fits
AI can help explain why a process is moving and recommend an action. It should not compute the number that is sent to the machine or bypass the limits: that is the job of validated algorithms and a deterministic guardian.
Standards and further reading
- Montgomery, D. C., Introduction to Statistical Quality Control
- Deming, W. E., Out of the Crisis (on tampering and over-adjustment)