From an ISO 17025 auditor perspective must micrometer calibration check anvil flatness?

[greif]

We are working toward 17025 accreditation.
This is strictly for in house micrometers we calibrate for our own use (where we occasionally use a micrometer to measure a customer part and then provide a 17025 calibration report on the size of the part). All the micrometers have carbide anvils, and are used very lightly.

Our current procedure calls for checking with optical flats (set of 4) if any wear is apparent on the anvils.
Is anvil checking something that must be done each time, or is our current procedure ok?

 

[AndyN]

If I understand correctly, an Accreditation Body (and their auditors) may require you to do this - unless you have data to show variation is insignificant. Since flatness may contribute to measurement uncertainty, I believe you'd need to show data to back up your decision.

 

[dwperron]

If you have written your own procedure, you can leave out the anvil checks in my opinion. Like AndyN said you will need to account for the possible measurement uncertainty contribution of anvil flatness as part of your risk analysis.

If you are referencing some other calibration procedure, such as Manufacturer Manual, GIDEP, ASME, etc. and their procedure calls for a flatness test you must either perform it or you will have to validate how your deviation from the standard procedure could affect calibration.

It only takes a couple of minutes to do the flatness checks on the micrometers, why not just check them?

 

[Prabhu B]

Hi, please clarify calibration required for new micrometer or vernier calibration.

 

[dwperron]

It all depends on your requirements.
What does your calibration process say you will do.
Does it say you will calibrate to the manufacturer's specifications?
Are you using your own procedure, or one you obtained? What does it say?
Are you meeting an external standard (ISO, AMSE, etc.) or contract requirements for calibrations.
Or are you just checking to see if it works.

The calibration required depends on your needs.