[SH...] Posted November 6, 2021 Share Posted November 6, 2021 I have to check symmetry w.r.t datum A_B. When I check symmetry w.r.t datum AB( stepped cylinder), I got 0.04. I created a secondary alignment by spatial datum AB and planer top plane, a completely constrained DRF. Using this alignment I got symmetry 0.314. I know according to drawing I should use datum AB only.But this is a correct method?. Symmetry control location and orientation, using datum AB we can control only location , can't control the orientation of the cylinder. My question is for symmetry rotational degrees of freedom is to be completely constrained??. Which one is correct results 0.04 or 0.314.IMG_20211106_220644.jpg Link to comment https://qualityforum.zeiss.com/topic/11666-symmetry-and-drf/ Share on other sites More sharing options...
[Ma...] Posted November 6, 2021 Share Posted November 6, 2021 First of all - A-B is not stepped cylinder. For symmetry i don't know if you can select another alignment. But seem like they don't care about perpendicularity with that plane as long as 20+/- 0,1 is good. For full alignment i would cut cylinder 8 J6 in center to get rotational point. Link to comment https://qualityforum.zeiss.com/topic/11666-symmetry-and-drf/#findComment-57910 Share on other sites More sharing options...
[Ün...] Posted November 8, 2021 Share Posted November 8, 2021 I have a symmetry query similar to this one. I'm using a cylindrical step and it's very successful. (A-B) 0.04 should be correct according to this picture. Link to comment https://qualityforum.zeiss.com/topic/11666-symmetry-and-drf/#findComment-57912 Share on other sites More sharing options...
[To...] Posted November 8, 2021 Share Posted November 8, 2021 Recalling points from cylinders into 1 cylinder is probably how I would approach this. A step cylinder would be used if cylinders were different sizes. I'm not 100% sure but I believe when you apply the symmetry to the cross cylinder, it may be doing a best fit rotation about the A-B axis until cross cylinder axis is straight, i.e. parallel to Z axis per view shown. When you add the planar, it is restricting the rotation and improving the result. Link to comment https://qualityforum.zeiss.com/topic/11666-symmetry-and-drf/#findComment-57914 Share on other sites More sharing options...
[Cl...] Posted November 8, 2021 Share Posted November 8, 2021 Please sign in to view this quote. viewtopic.php?f=13&t=1778 Link to comment https://qualityforum.zeiss.com/topic/11666-symmetry-and-drf/#findComment-57916 Share on other sites More sharing options...
[An...] Posted November 8, 2021 Share Posted November 8, 2021 Please sign in to view this quote. Link to comment https://qualityforum.zeiss.com/topic/11666-symmetry-and-drf/#findComment-57918 Share on other sites More sharing options...
[Sh...] Posted November 8, 2021 Share Posted November 8, 2021 Please sign in to view this quote. I understand that these two bores are not different sizes, is there any sort of reason Step Cylinder cannot be used? I have not had any issues in this situation using it... Link to comment https://qualityforum.zeiss.com/topic/11666-symmetry-and-drf/#findComment-57920 Share on other sites More sharing options...
[To...] Posted November 8, 2021 Share Posted November 8, 2021 Please sign in to view this quote. No. Link to comment https://qualityforum.zeiss.com/topic/11666-symmetry-and-drf/#findComment-57922 Share on other sites More sharing options...
[SH...] Posted November 8, 2021 Author Share Posted November 8, 2021 Please sign in to view this quote. Yes, I asked to my customer ( not to designer customer) and he says use both plane ( Top)and axis ( A-B) for symmetry. I think he has more sense than that designer. Link to comment https://qualityforum.zeiss.com/topic/11666-symmetry-and-drf/#findComment-57924 Share on other sites More sharing options...
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