The auditor picks up a micrometer
It is audit day. The auditor walks to a machine, picks up the micrometer beside it and asks for its calibration certificate. The quality manager opens the spreadsheet. The serial number is not on it. It turns out to be a setter's own micrometer, brought from home, used on every job on that machine for the last year.
Or the calibration house returns a bore gauge with a note that it was out of tolerance when received. Which jobs was it used on in the last twelve months? Nobody can say.
Why the gauge list drifts
Gauges are small, useful and portable. They move from the inspection room to a cell, into a toolbox, onto another machine. Personal gauges get used alongside company ones. The calibration spreadsheet knows what should exist, not where it is or what it has been used for.
- The register is a spreadsheet maintained by one person.
- Personal gauges are used on the shop floor without being registered.
- Due dates pass because the reminder is someone remembering to look.
- Certificates from the calibration house are filed separately from the list.
- Inspection records do not say which gauge took the reading.
What the gaps cost
An audit finding, at the least. More seriously, if a gauge is found to have been reading wrong, you may have to contact customers about parts measured with it, and without records you cannot limit that to the jobs actually affected. The time spent rounding up gauges before each calibration visit is a smaller but recurring cost.
The gauge register we build
- Every gauge gets a durable label with a unique ID and barcode. Personal gauges are either registered or kept off the shop floor, as your procedures decide.
- The register holds type, range, serial number, calibration interval, location and status: in use, due, away for calibration, quarantined or retired.
- Reminders go to the quality manager ahead of due dates, and a list of gauges due is produced for the calibration house visit, with their last known location.
- Calibration certificates are uploaded or emailed in and read automatically: the gauge ID, the date, the result and the next due date are pulled out for a person to confirm.
- Digital check sheets and inspection reports record which gauge was used for each reading, by scan or selection.
- If a gauge comes back with an out of tolerance result, the register lists every job and inspection it was used on since its last good calibration.
| Question | Answered by |
|---|---|
| Where is gauge G-214? | Last scan location |
| What is due next month? | Due list for the calibration visit |
| Show me its certificate | Certificate stored on the gauge record |
| Which jobs did it measure? | Readings linked to the gauge |
| Is this gauge allowed on the floor? | Status: in use, due, quarantined |
After it is running
The spreadsheet is gone and so is the scramble before an audit. Gauges past their date show as due before they are overdue, and a gauge that is quarantined cannot be selected on a check sheet. When the calibration house reports a problem, the list of affected jobs is a report, not a guess.
The quality manager also gets a view of the gauge stock as a whole: which gauges are duplicated, which are never used, and where a second gauge would save people walking across the shop to borrow one.
Could you answer the auditor?
- Gauge calibration is tracked in a spreadsheet.
- Personal gauges are used on jobs.
- Due dates have been missed.
- Certificates are filed separately from the gauge list.
- You could not say which jobs a particular gauge was used on.