Calibration Interval - AS9100 - Control of Monitoring and Measuring Equipment

Having an 'animated' discussion with a peer whose opinion I value highly; however on this topic we disagree, and seeking some thoughts from the assembled multitude of QA pros.

As9100 (whatever) tells us that control of monitoring and measuring equipment is to be done at specified intervals, and that we can set them based on whatever criteria we choose/deem appropriate.

The gear in question happens to be some floor fitting interface fixtures, used to 1) locate the monument-to-floor fittings prior to bonding. The locations are derived from the model and the fixtures were machined and then digitally scanned to a magnitude greater than the tolerance of the fittings' locations. And yes the scanning equipment itself was all calibrated.

Here is the point of contention: since these plates are made of 1/2" thick aluminum any damage that affects the fitting interface will be quite visible and because of that, I called for a 'One Time Only (OTO)' cal interval. The quality plan for this project and project unique cal process defines this and also allows it as long as no damage to the fixture is present.

My friend does not accept a OTO; instead he maintains that I should have some interval, even if it is a 5 year interval.

When I ask him why, he just repeats himself. I don't want to put us in a position of missing a 5 year window, and at the same time am confident any damage that would impact the fitting locations would be blatantly obvious.

Your thoughts and comments please.

Thanks.

Please provide some more details about why you think damage will be quite visible.

It seems like you could have damage that is just enough to make the fixture not work correctly but might not be obvious. Being a softer metal, aluminum may wear over time and the fixture may slowly shift away from the desired alignment.

A6Intruder said:

The gear in question happens to be some floor fitting interface fixtures, used to 1) locate the monument-to-floor fittings prior to bonding. The locations are derived from the model and the fixtures were machined and then digitally scanned to a magnitude greater than the tolerance of the fittings' locations. And yes the scanning equipment itself was all calibrated.

Your thoughts and comments please.

Thanks.

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From what you describe, this sounds much more like an assembly fixture, rather than an inspection, measuring, test device. If it is indeed a production tool, then the requirement you are concerned with does not apply. It would have to be validated and maintained, but not "calibrated".

I agree with what Sidney said. Calibration is required for measuring equipment. Is there something else that is used to measure the product that will detect a problem if the fixture is damaged or wears? If so, this is what should be periodically calibrated.

As far as maintenance, aluminum fixtures are very prone to wear. If it's being used frequently then I would expect that it would wear over time and eventually won't be able to hold a tolerance. I don't know what kind of tolerances you have, but this should be considered. Periodic verification of the tooling or ongoing measurement of resulting product would detect this.

Thanks for the inputs; I see that I wasn't clear ( working from a position of 'insider trading'):

The fixture has bolt holes that the floor fittings are fixed to. Then the entire fixture/fitting assembly is mated with our monument. the monument is constructed of honeycomb core panels and the area where the fittings are inserted is cleared away and after the fittings have been inserted, we then bond them in place. The check fixture remains until the adhesive cures. Since the through holes for the bolts is not an interference fit, any wear to these holes would be insignificant. My tolerance is +/- 0.030" on the monument, and by fixture tolerance was +/- 0.010" for the bolt hole centers.

I'm leaning toward what Sidney said as well. It almost sounds like it's a production check fixture that doesn't need to be handled by quality for acceptance. Is this used for acceptance? If not it sounds like production upkeep.

We use it as to verify location, so yes it is an acceptance tool and thus requires calibration. It is called out in not only the manufacturing drawings, but also in the customer's source inspection work order. The floor fittings have no adjustment and MUST fit, so this is our only way to ensure there is no installation issue.

A6Intruder said:

We use it as to verify location, so yes it is an acceptance tool and thus requires calibration. It is called out in not only the manufacturing drawings, but also in the customer's source inspection work order. The floor fittings have no adjustment and MUST fit, so this is our only way to ensure there is no installation issue.

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I agree with your coworker that if calibration is required, a one-time calibration is insufficient. AS9100 says:

AS9100 Rev D clause 7.1.5.1 said:

The organization shall ensure that the resources provided:

a. are suitable for the specific type of monitoring and measurement activities being undertaken;

b. are maintained to ensure their continuing fitness for their purpose.

The organization shall retain appropriate documented information as evidence of fitness for purpose of the monitoring and measurement resources.

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Bullet point "a" would be covered by initial calibration. Bullet point "b" would be covered by periodic verification/calibration. The last sentence requires records as evidence that it continues to be fit for use. Also there is the part of 7.1.5.2 that you mentioned including "specified intervals" which would not be met with a one-time calibration.

There are many programs that have calibrate (or verify) before use categories. There is no date-driven interval. A mechanical fixture with dimensional requirements seems like a good candidate.