[To...] Posted February 14, 2020 Share Posted February 14, 2020 Sorry about the brain not working today, but what would be the difference between Roundness and Surface Profile on this sphere? Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/ Share on other sites More sharing options...
[Ri...] Posted February 14, 2020 Share Posted February 14, 2020 Technically Roundness is a single cross-section. Surface Profile would apply to the surface. The Surface Profile is most likely also taking into account the diameter. Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-91990 Share on other sites More sharing options...
[An...] Posted February 14, 2020 Share Posted February 14, 2020 Please sign in to view this quote. Roundness never takes into account the basic diameter. It's a tolerance of form but not of size. (Tom: hello?) See attached.Contribution_14_02_2020_1.pdf Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-91992 Share on other sites More sharing options...
[Ri...] Posted February 14, 2020 Share Posted February 14, 2020 Please sign in to view this quote. I didn't say that Roundness takes size into account, I said that most likely the Surface Profile does though, especially if it is a closed loop. Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-91994 Share on other sites More sharing options...
[An...] Posted February 14, 2020 Share Posted February 14, 2020 Yep! Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-91996 Share on other sites More sharing options...
[To...] Posted February 14, 2020 Author Share Posted February 14, 2020 I told you I wasn't thinking clearly.... Thank you. Richard, I understand that we typically think of roundness being applied to a single circle section but Calypso allows you to select a cylinder and a sphere. When I have applied roundness to a cylinder, I happen to get the same number as the cylindricity. I assume the same would apply on a sphere and sphericity. Don't know. Haven't tried it. YET. Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-91998 Share on other sites More sharing options...
[Ma...] Posted February 14, 2020 Share Posted February 14, 2020 Roundness tolerance applies to ANY circular section of an element. If you apply a roundness characteristic a feature with multiple circular sections in Calypso, it outputs the total form error as a result. Each circular section needs to be evaluated separately for roundness and the greatest deviation should be compared to the tolerance. Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-92000 Share on other sites More sharing options...
[To...] Posted February 14, 2020 Author Share Posted February 14, 2020 Please sign in to view this quote. If roundness is applied to a cylinder and is within the specified tolerance, then any of the circular sections would automatically be within the roundness spec. Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-92002 Share on other sites More sharing options...
[Ma...] Posted February 17, 2020 Share Posted February 17, 2020 Please sign in to view this quote. It is true Tom, that if a roundness tolerance is applied to a cylinder in Calypso an in spec. result would guarantee that all the circular sections were also in spec. The problem with this method would be that there are circumstances where you would reject good parts. For instance, a cylinder with a 0.1 mm size tolerance and a 0.005 mm roundness tolerance. If the part had all circular sections within tolerance but was tapered 0.025 Calypso would output the cylindricity error for roundness and fail the part. Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-92004 Share on other sites More sharing options...
[An...] Posted February 18, 2020 Share Posted February 18, 2020 Please sign in to view this quote. I would'nt think so. Think of a cross section that is oval and an axis that is tilted. See attached.Contribution_18_02_2020_1.pdf Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-92006 Share on other sites More sharing options...
[To...] Posted February 18, 2020 Author Share Posted February 18, 2020 Please sign in to view this quote. I don't see your point. Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-92008 Share on other sites More sharing options...
[An...] Posted February 18, 2020 Share Posted February 18, 2020 Uuuups! You where faster than me. Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-92010 Share on other sites More sharing options...
[To...] Posted February 18, 2020 Author Share Posted February 18, 2020 Please sign in to view this quote. Yes, I agree. I wasn't advocating the use of roundness on a cylinder but just pointing out a particular condition exists. 😃 Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-92012 Share on other sites More sharing options...
[To...] Posted February 18, 2020 Author Share Posted February 18, 2020 Please sign in to view this quote. Yes, I see your example. This phenomenon would occur if measured as individual circles. The measurement of the circular sections should be perpendicular to the axis, even if measured as individual circles. Andreas, I have edited/deleted some of replies because I came to a better understanding of your drawing. Link to comment https://qualityforum.zeiss.com/topic/16512-roundness-vs-surface-profile/#findComment-92014 Share on other sites More sharing options...
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