[Aa...] Posted May 28, 2021 Share Posted May 28, 2021 I know there have been other threads on this subject, but I just want to see if my understanding is perceived to be correct by everyone else, since I've been in a conversation with an engineer at Zeiss who seems to disagree with me. Generally, the Calibration Certificates for the Ref Spheres supplied with the machines have a much higher uncertainty than the stated accuracy of the machine. This is not a problem, since that sphere is used for qualification in the ISO 10360-2 verification of the machine. (The CMM and RS are verified as a unit.) For that reason, using a different reference sphere for qualification breaks the chain of traceability through the verification artifact. I believe this is supported by the first paragraph of the attached notice.ref spheres.pdf Link to comment https://qualityforum.zeiss.com/topic/12788-switching-out-reference-spheres/ Share on other sites More sharing options...
[Ma...] Posted May 28, 2021 Share Posted May 28, 2021 The stated uncertainties on the certificates for the spheres we have from Zeiss are: Diameter 0.0003 mm Roundness 0.00004 mm Link to comment https://qualityforum.zeiss.com/topic/12788-switching-out-reference-spheres/#findComment-64394 Share on other sites More sharing options...
[Aa...] Posted May 28, 2021 Author Share Posted May 28, 2021 Please sign in to view this quote. Right. It's the same for the one I'm looking at. (Except mine doesn't list roundness or roundness uncertainty, and it says the radius is outside the Lab's scope of accreditation.) The certificate for the machine lists a base uncertainty of 0.0001 mm. So basically, I could use the machine to measure the radius of the RS, and that measurement would be of greater value than the one listed on the Certificate. 🤣 Link to comment https://qualityforum.zeiss.com/topic/12788-switching-out-reference-spheres/#findComment-64396 Share on other sites More sharing options...
[Is...] Posted June 1, 2021 Share Posted June 1, 2021 I have the impression that you are mixing concepts: etc, etc, etc... Link to comment https://qualityforum.zeiss.com/topic/12788-switching-out-reference-spheres/#findComment-64398 Share on other sites More sharing options...
[Aa...] Posted June 4, 2021 Author Share Posted June 4, 2021 Okay, thanks. So, which concepts am I mixing, exactly? Link to comment https://qualityforum.zeiss.com/topic/12788-switching-out-reference-spheres/#findComment-64400 Share on other sites More sharing options...
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