[Lu...] Posted January 14 Share Posted January 14 Hello, I decided to measure a few ring gages with our Accura II, and I am seeing a result of .0002avg over nominal with most of our probes (including the master probe). I am measuring as a single hit circle, scanned circle, and a single hit cylinder. I am reporting as an average, inner and outer tangential, and 2-point diameter. Our 3MMX75MM probe generated the worst result (pushing .0004avg over nominal). The best result I found was measuring a 4" ring gage with the master probe. The average diameter for that was .00008 above nominal, but the inner and outer tangential had a .0002 spread. I am using Class X and class XX calibrated ring gages. Any thoughts or suggestions? Is this normal? our Accura was just calibrated by Zeiss a month ago. Thanks Link to comment Share on other sites More sharing options...
[DW...] Posted January 14 Share Posted January 14 Please sign in to view this quote. Go to your reference sphere management.. Does the highlighted value in your software match the value of your reference sphere certificate? Link to comment Share on other sites More sharing options...
[Lu...] Posted January 14 Author Share Posted January 14 Sorry, I can't find certs...I found a cert for one of our 3 spheres but it is pretty outdated cert and it is for our smallest sphere (8mm sphere for calibrating 1mm probes). The radius is off by 0.00044196mm and the roundness is off by 0.058 microns. Perhaps our other calibration spheres are off even more. I guess I have no way of knowing if this is what is causing the issue without sending the spheres out for calibration? Link to comment Share on other sites More sharing options...
[Lu...] Posted January 14 Author Share Posted January 14 I do have serial numbers on the spheres...maybe Zeiss can look up the certs for me? Link to comment Share on other sites More sharing options...
[DW...] Posted Wednesday at 05:47 PM Share Posted Wednesday at 05:47 PM (edited) Please sign in to view this quote. Yes, without the certificates you have a big unknown value in your sphere radius. The number supplied by the Zeiss certificate would be input by you as the operator when setting up your spheres to allow the software to do its calculations. It might be worth calling the Zeiss 800 number or reaching out to Please sign in to view this username. . The other option would be to have it calibrated by a reputable lab that you trust. Keep in mind, the theory of the value being off in your sphere management is just a beginning point when troubleshooting your initial comments. Edited Wednesday at 05:47 PM Link to comment Share on other sites More sharing options...
[Lu...] Posted Friday at 10:11 PM Author Share Posted Friday at 10:11 PM Thank you. Turns out, the issue was mainly caused by using double-sided tape. The ring gage was moving. We may still have a small issue (<.0001) related to the calibration sphere - I am going to try to find those certs. Link to comment Share on other sites More sharing options...
[Je...] Posted Saturday at 03:19 AM Share Posted Saturday at 03:19 AM Please sign in to view this quote. Lukas, great job on figuring out the root cause of the problem. That's a vital skill in metrology. I know I've run into similar situations before of discovering that the main contributor to measurement error was fixturing or the movement of the workpiece. We've all been there. Link to comment Share on other sites More sharing options...
[Mi...] Posted 14 hours ago Share Posted 14 hours ago This is a great argument for good fixturing and Looped Base Alignments, especially if you have PCM so you can make the program stop if the Alignment value never resolves down to your limit. Convincing a programmer to do it when they are convinced they don't need to is hard, but the results are undeniable. Link to comment Share on other sites More sharing options...
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