Measurement Uncertainty for Calibrating Custom Check Fixtures with a Portable CMM

[Jgryn]

Am I on the correct track? What am I lacking? Is there an easier way to do things? Any guidance would be appreciated.

Small company with 1 and 1/2 technicians will be pursuing compliance to ISO 17025 for very occasional on-site calibration (verification) of large check fixtures with very wide tolerances. (ie... not worth the trip to the calibration laboratory). Most customers will either calibrate their own equipment, or send it out for calibration to a controlled lab. It is only when size and required accuracy needs to be accommodated do we fill a niche for on-site calibration and therefore would prefer to find the information we need for a) free, b) purchase if necessary, or c) hire a consultant as a last resort.

We have two portable CMM's. A Faro platinum arm and a Faro Laser Tracker.

Our plan is to:

1 - Identify all the possible contributers for the majority of situations, we would encounter, creating a easy to customize for any situation type of document to be evaluated each time we create a quote.
2 - Quantify these items (would not mind some help here...). Studies will be required.
3 - Set up uncertainty studies to determine the significance of all the factors.
4 - Determine the best measurement uncertainties.

Again any suggestions and guidance would be greatly appreciated.

Yes, I've read the 17025, GUM, TN 1297, EA4/2 and the UK guidance to 17025. My head is still reeling from the math, but I'll get it eventually...

[Hershal]

Given your location, I suspect you will use CLAS or SCC for your accreditation.....best thing is to talk to them and see if they can give you some direction.....they can't do consultancy of course, but should be able to point you in the right direction.

Oh, and go to an uncertainty training course.

[Stijloor]

Originally Posted by Hershal

Oh, and go to an uncertainty training course.

Thank you Hershal.

Uncertainty Training Courses.

Stijloor.

[Jgryn]

The UKAS publication M3003 has a good example (see page 22, section 7) using a weight. Does anyone know a source that repeats the same steps for a CMM measuring a hard gauge like a check fixture?

http://www.ukas.com/Library/download...ions/M3003.pdf

Thanks,

Jen