[An...] Posted October 21, 2024 Share Posted October 21, 2024 Good morning, I had some free time and decided to look into something that I realized I did not know the answer to: How much variation is there in the sigma values for my styli between qualifications? I ran my qualification program 10x and reported the sigma values in a trend protocol, which I have attached. I realized I also need the answer to another question if I am going to fully understand this little exercise I have done, which is the question I am posing to the group: How much variation should there be/is typical in the sigma values between qualifications? Link to comment https://qualityforum.zeiss.com/topic/4588-qualification-variation/ Share on other sites More sharing options...
[Ri...] Posted October 21, 2024 Share Posted October 21, 2024 We always taught people that your sigma value, for a robust stylus system, should be no more than 35% of your MPE allowance. Given that value, I think this would be a case that I wouldn't really lose a lot of sleep over the variation. The sigma is the variation of the points taken for the probe qualification, so applying a constraint on the variation of the variation would be a little overboard. IMO that is. Link to comment https://qualityforum.zeiss.com/topic/4588-qualification-variation/#findComment-14140 Share on other sites More sharing options...
[An...] Posted October 21, 2024 Author Share Posted October 21, 2024 Thank you for your response, Richard. That's exactly what I was hoping to hear. Link to comment https://qualityforum.zeiss.com/topic/4588-qualification-variation/#findComment-14142 Share on other sites More sharing options...
[Je...] Posted October 21, 2024 Share Posted October 21, 2024 Please sign in to view this quote. . Andy, come work for my company. I appreciate the type of curiosity you've shown here. Nice work. . Link to comment https://qualityforum.zeiss.com/topic/4588-qualification-variation/#findComment-14144 Share on other sites More sharing options...
[Ri...] Posted October 21, 2024 Share Posted October 21, 2024 Attached is an Excel workbook I use. It has data for two Micura's. This is data based on 20 qualification runs of 5 different probes. (Three probes are in both +X and -X axis). This was run on Daily Qualifications, we now run on Weekly Qualifications. I have data for 11 months now of weekly qualification, it mirrors the daily runs. P.S. The workbook also does Bilateral. I think I may have got this from this forum. Use it as you wish.#Cp-Cpk_Micura CMM Probes 20x.xlsx Link to comment https://qualityforum.zeiss.com/topic/4588-qualification-variation/#findComment-14146 Share on other sites More sharing options...
[Je...] Posted October 21, 2024 Share Posted October 21, 2024 Please sign in to view this quote. . Rick, that's a great spreadsheet. Thanks for sharing it. Question: Why do you think machine #251 struggles with the 2mm system compared to #252? Does #251 ever hear "Why can't you be more like your sister?" 😂 It seems like they both do better with the 0.5x20 probe. Do you think weight is the main contributor here? What sensor does each have? . . Link to comment https://qualityforum.zeiss.com/topic/4588-qualification-variation/#findComment-14148 Share on other sites More sharing options...
[Ri...] Posted October 22, 2024 Share Posted October 22, 2024 Please sign in to view this quote. Well, now I have to investigate this. 🤣 They are identical Micuras and both have VAST XT Gold sensors. All of the probes are identical in build. Link to comment https://qualityforum.zeiss.com/topic/4588-qualification-variation/#findComment-14150 Share on other sites More sharing options...
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