Handling of measurement device calibration for inactive devices

[jwbrouse]

Greetings, all.

I have a question regarding calibration of measuring devices; specifically, how the timing for calibration of inactive devices should be handled.

We recently had our IATF recertification audit, and one of our nonconformities was for calibration timing of measuring devices.

In the system that we use for device management, if a device is inactive, it pauses the calibration clock. In this case, we had a set of gage blocks that were purchased and calibrated in Nov-2020, then set as inactive. They remained inactive until Jan-2023, at which point the system started the 2-year calibration cycle, and gave a next calibration date of Jan-2025. Knowing that it is a 2-year cycle, the auditor dinged us for having the calibration due > 4 years after last calibration.

How do y'all handle this type of scenario? Any assistance is greatly appreciated.

 

[Ashland78]

Having worked in metrology labs over 20 years, there are things that can change, "drift" when inactive.
For instance, having visited Fluke for calibration lab management training, they said electronics that sit in a warehouse that is uncontrolled for long time (6 months+), should be recalibrated before use as it will not read the way it was when it left the building.

If you have thread plug gauges that have the wax over the threads, you could "activate" this when put in use.

The gage blocks I question if they had enough of the film lubricant on them when they were put into use. Were they stored correctly??? Where are they used? What grade of blocks are they? You do realize that these are at times the "standard" to calibrate other devices such as calipers, or micrometers. These need to be accurate for this purpose.

Now. If I have sent these same gage blocks out 2 consecutive years, and the results come back with no significant change then I would decrease calibration cycle to 3 years.

Why? I have evidence that they remain capable. The frequency is also defined in the metrology manual (procedure), that calibration engineer can make these decisions based on knowledge of the gage and process.

 

[Quality-Nation]

We recently had our IATF recertification audit, and one of our nonconformities was for calibration timing of measuring devices

What was the finding? Is it accurate?

 

[Tidge]

We recently had our IATF recertification audit, and one of our nonconformities was for calibration timing of measuring devices.

In the system that we use for device management, if a device is inactive, it pauses the calibration clock. In this case, we had a set of gage blocks that were purchased and calibrated in Nov-2020, then set as inactive. They remained inactive until Jan-2023, at which point the system started the 2-year calibration cycle, and gave a next calibration date of Jan-2025. Knowing that it is a 2-year cycle, the auditor dinged us for having the calibration due > 4 years after last calibration.

How do y'all handle this type of scenario? Any assistance is greatly appreciated.

In this specific case it sounds as if the calibration cert came from a supplier; is there evidence from the supplier that they previously agreed to stand by the calibrated state of those specific gage blocks in the scenario? If this turns into a post hoc rationalization and had not been an established part of the calibration program.. .I think the auditor was onto something. Note that I have no experience with IATF 16949 audits, but I worked in an accredited general metrology lab for many years.

Generally: I would not expect devices or references of any sort to maintain a calibrated state beyond their original date simply because a label was applied to them. I have certainly seen devices/references pass the next scheduled calibration without the need for adjustment, but data from those would be an argument for possibly changing their calibration frequency.

 

[ChrisM]

Gage blocks are not going to wear when they are not in use. If they have been stored under controlled temperature and humidity conditions, it is a very fair assumption to state that they will not degrade and will maintain their "calibration status". I have worked at places before where we have effectively quarantined thread gages and plain gages after calibration, kept them in a controlled environment and re-started their calibration cycle from the time that they were then removed for first use after calibration.

If your procedure clearly defined what you were doing as per my comments above then I think your auditor has been unfair (and is incorrect) in raising a nonconformance

 

[Ashland78]

Gage blocks are not going to wear when they are not in use. If they have been stored under controlled temperature and humidity conditions, it is a very fair assumption to state that they will not degrade and will maintain their "calibration status". I have worked at places before where we have effectively quarantined thread gages and plain gages after calibration, kept them in a controlled environment and re-started their calibration cycle from the time that they were then removed for first use after calibration.

If your procedure clearly defined what you were doing as per my comments above then I think your auditor has been unfair (and is incorrect) in raising a nonconformance

Agreed, we don't know though what the environment is like based on info. That is the big factor. Additionally, is this written in their procedure?

 

[Golfman25]

Your auditor is a jerk. Gage blocks just don’t “go bad” When not used excessively. I have seen gage blocks 20+ years old that have been stored and are perfectly fine. Did the “sticker” on the blocks say calibration due in 2022 or 2025?

 

[Ron Rompen]

I agree with Golfman. Your auditor is looking to write 'something' as a finding to justify his/her existence. I have gauges that have been set as inactive, and if/when they are brought back into use, they are calibrated before being released for general use. That is what my calibration procedure says, and that's what I do. the standard doesn't say how OFTEN you have to calibrate your gauges, doesn't say HOW you do it....just says you have to have a documented system that describes what you do and how you do it.

 

[Quality-Nation]

Your auditor is looking to write 'something' as a finding to justify his/her existence.

Welcome to the world of IATF audits

 

[Tidge]

I have gauges that have been set as inactive, and if/when they are brought back into use, they are calibrated before being released for general use. That is what my calibration procedure says, and that's what I do. the standard doesn't say how OFTEN you have to calibrate your gauges, doesn't say HOW you do it....just says you have to have a documented system that describes what you do and how you do it.

This is always what I've done when reactivating references and equipment that are past the last calibration due date. In practice: I've always seen stuff go into a deactivated state because the equipment wasn't being used as a cost saving measure.

It's been a toss-up if there is a final calibration before inactivating, because if a tool had been used and is later found to be out-of-cal upon attempted reactivation, that much more time has passed to assess what might have been impacted. If the equipment truly hadn't been used, this is not an issue.