Vision System Optical Calibration Standard

[3D-man]

I would like to add one of our vision systems to our scope of accreditation but a big hang-up has been finding a good optical length standard that itself is accurate enough so our measurement uncertainty has a chance of being as good as or near the rated machine accuracy. I have seen the nice and seemingly custom built optical standard the mfr uses when performing the periodic calibration.

To be specific, I'm looking for an optical length standard that is at least 12" long with an accuracy of 0.5 microns. Then of course, I'll need to be able to find a source to calibrate it (is there a cal lab besides NIST that can really do it?).

Am I dreaming or is this a reasonable request?

 

[BradM]

If you find it, let me know.)
I think that uncertainty is near NIST reported numbers.
We have an accurate an nikon scales, but nothing in that range.
Sorry I can't help.

 

[bobdoering]

Maybe this article can provide some direction!

 

[3D-man]

Thanks Bob. The article is a good one but my issue is finding good a calibration standard, as in physical reference of known length(s), to use to run a series of test measurements to determine the measurement uncertainty of one of our vision systems. For example, Applied Image Group and Edmund Optics both sell such physical reference specimens but none are accurate enough for what we need.

 

[bobdoering]

I came across it looking for glass standards - which I think you can get in the length and tolerance you need - but not sure where. I have seen them at shows. They may even use them in integrated circuit manufacture. I thought the device they showed in the photo was of interest.

 

[3D-man]

Yes, the device pictured in the article is most interesting. It appears to completely circumvent the complexities of calibrating a CMM checkmaster by having a series of different lengths that can themselves be calibrated on a large super-mic. We have a checkmaster for CMMs but the one in the image is probably more accurate for the aforementioned reason.

 

[Sam Lazzara]

Contact this company.
http :// www. mastergt. com/metrology-services/mechanical-calibration.aspx - DEAD - 404 - LINK UNLINKED

They should be able to point you in the right direction.