NIST Traceability - Calibrating a grid w/ laser interferonmeters and microscopes

[Sentient]

Hello

We're making a large glass grid with targets on it, and planning to calibrate this grid on a large X,Y,Z stage system with a laser interferonmeter/s and microscopic optics.

For this process, what steps would need to be taken to achieve NIST Traceability on the large grid?

I am most appreciative for your informed replies.

 

[Jerry Eldred]

I am not familiar with the specifics of your equipment. But for it to be NIST traceable, it must somehow be compared with NIST traceable length. If your XYZ stage system has been calibrated with NIST traceable standards, that will provide traceability. If your XYZ system is not calibrated, you will need to compare its accuracy against traceable standards.

Sorry for the redundancy. I think this should be straightforward. Hope that is of help.

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[Graeme]

I was briefly involved in a similar project about 8-9 years ago. The client then had a CMM system that used a glass grid as the reference standard, and then the CMM made measurements of other large, flat objects.

My recollection from then is that NIST (Gaithersburg, MD) does have a calibration service for these grids. If you are manufacturing the grids, you may want to consider having NIST calibrate your master grid and use that to transfer the measurements. If you are a user, you may want to check with the manufacturer of the grid for traceability.

All of your dimesional measuring devices need to be calibrated, of course. That is, as I recall, a fairly routine and easy process with the laser interferometer. (At least, with the brand we were using then.)


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Graeme C. Payne
ASQ Certified Quality Engineer
[email protected]

[This message has been edited by Graeme (edited 28 February 2001).]

 

[Sentient]

Thank you for your replies!

 

[metrologyguy]

NIST traceability has recently been redefined. In the good old days if you had a cert with a NIST number, it was assumed to be traceable. For the real definition, I recommend you check out www.a2la.org.

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