[Er...] Posted December 10, 2021 Share Posted December 10, 2021 What is the best practice for inspecting this composite position. Primarily, the .25mm position to A, B-C? Assume the 4 holes in questions refer to the position requirement. Link to comment Share on other sites More sharing options...
[To...] Posted December 10, 2021 Share Posted December 10, 2021 For the top tier, using B for the Secondary and C for the Tertiaty, the origin of the DRFis at B and the Y axis drives thru C. For the lower tier, I discovered something that I was not expecting. The origin of the DRF was not at B or the mid-point of B-C. It is at the edge of Plane_A See screen shots.A B C.JPGA B-C.JPG Link to comment Share on other sites More sharing options...
[Er...] Posted December 10, 2021 Author Share Posted December 10, 2021 This is why I asked. I thought B-C would mean the Origin would be The symmetry of the 2 holes. Is this correct to ASME Y14.5, and calypso is using an ISO interpretation, or am I not understanding correctly? Link to comment Share on other sites More sharing options...
[To...] Posted December 11, 2021 Share Posted December 11, 2021 Below is a youtube link that does a decent job describing the multiple single segment feature control frames, in particular at 1:02. The whole video is worth watching. This guy has several videos. https://www.youtube.com/watch?v=iSdMpgV ... =8&t=3692s I'm not in front of Calypso so I can't test. What happens when you use A as Primary and B-C as Secondary with regards to best fits? If you open the default printout, it should show you. Link to comment Share on other sites More sharing options...
[Pe...] Posted December 13, 2021 Share Posted December 13, 2021 Please sign in to view this quote. My understanding is that B-C creates a line axis of datum that would constrain only 2 translations of freedom So for the second position you could still use the same datum frame at the tighter tolerance, but you would constrain it to the "Only Y" direction since B-C creates an infinite line that shouldn't care about X. You would get an odd tolerance zone like this: Please sign in to view this quote. I believe it may be gathering the Y position from the feature origin of Plane A (or base alignment if you defined one) since the lower tier doesn't define any Y. Link to comment Share on other sites More sharing options...
[Er...] Posted December 13, 2021 Author Share Posted December 13, 2021 Please sign in to view this quote. Thank you, That makes sense. They only thing that makes me question where to origin would be is this statement I found in the ASME Y14.5. This is from 2009. If B and C doesn't matter which is listed first, it makes me think that the origin now become the center of the 2. And if that's the case, it may translate to the center of the 2 holes rather than to Datum B in line with Datum C. Link to comment Share on other sites More sharing options...
[Ro...] Posted December 14, 2021 Share Posted December 14, 2021 Datum B-C is considered 1 datum (codatums) and each hole has equal precedence. The origin is the symmetry of the 2 holes. Level/origin to A, rotate to the axis of B-C, origin to the symmetry of B-C. Link to comment Share on other sites More sharing options...
[Cl...] Posted December 14, 2021 Share Posted December 14, 2021 Please sign in to view this quote. Isn't that just for the bottom tier? Link to comment Share on other sites More sharing options...
[Er...] Posted December 14, 2021 Author Share Posted December 14, 2021 Please sign in to view this quote. Yes, Clark, this is specifically what I was asking about. Link to comment Share on other sites More sharing options...
[Cl...] Posted December 14, 2021 Share Posted December 14, 2021 Sorry I missed that. Link to comment Share on other sites More sharing options...
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