Possible escapes due to caliper out of calibration

[Eloy Gomez]

Hello: during an external audit of the calibration system it was discovered that a caliper that was sent our for calibration returned not able to be calibrated. A C/A was issued because we were not able to determine on which units was this pair of calipers used and we could not determine if we sent non-conforming parts to our customers.

We would like to start monitoring this but we are not sure how or what controls should we have in place? What would be an appropiate root cause corrective action? and long term solution?

[BradM]

Hello Eloy!

Now when you sent the calipers out for calibration, were they able to get any as-found data? What happened to the calipers?

To me the question is whether it was possible that people were using the calipers with excessive error present.

As to the root cause, I would say it is dependent on the nature of damage to the instrument. Also, how has the calibration data looked each time it was calibrated? Was it close to being out? If so, you probably want to get shorter intervals.

Also, you might consider purchasing (and have calibrated) a few gauge blocks to check them out periodically to see if they are drifting.

Have you analyzed the historical data? That should give you an indicator as to how the instrument has been performing.

Hope something here is of help.

[harry]

Brad had covered most of the areas. A recent and related thread worth reading is: What to do with Prior Analysis after instrument was Out Of Calibration (OOC)?

[howste]

Originally Posted by Eloy Gomez

We would like to start monitoring this but we are not sure how or what controls should we have in place? What would be an appropiate root cause corrective action? and long term solution?

It's not clear to me exactly which of several problems you are trying to prevent from recurring. I think you need to start by defining which problem(s) you are trying to solve.

Problems I see:
- A set of calipers went out of tolerance
- The out-of-tolerance calipers were not detected before calibration
- Although the calibration source found that the calipers were out of tolerance, the external auditor identified the problem before internal personnel did
- It's unknown how far out of tolerance the calipers were
- Which product was checked with the calipers and the risk of nonconforming product is unknown

Each one of these problems could have separate root causes and actions

[arios]

Hi Eloy

You have received great feedback from the other folks.

If I can help a bit I would just add that a risk assessment would be beneficial. I mean, think on the worst case scenario considering the product that would have the greatest impact based on its tolerances and determine how severe the impact could had been. Also consider if there were reduntant tests either upstream or downstream in the process that could serve as a reference for your rationale.

I hope this situation had not a severe impact. In most of the cases I have seen there is not and I hope this is the case

Greetings paisano!
Alberto