[To...] Posted January 26, 2021 Share Posted January 26, 2021 Hello everyone. It is my opinion that Datum C has no impact on a profile call-out as Datum's A and B restrict all degrees of freedom. Does anyone have a different opinion with an explanation why?Screenshot 2021-01-26 114103.jpg Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/ Share on other sites More sharing options...
[Ri...] Posted January 26, 2021 Share Posted January 26, 2021 I would agree. Looks like someone hit the copy/paste function in their drawing. Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-68982 Share on other sites More sharing options...
[To...] Posted January 26, 2021 Author Share Posted January 26, 2021 here's the real detail on B. Sorry. One more detail Per AMSE Y14..5-1994 . .Screenshot 2021-01-26 113303.jpg Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-68984 Share on other sites More sharing options...
[Ri...] Posted January 26, 2021 Share Posted January 26, 2021 Ohhh. That makes it more interesting. The engineer might be thinking that B wouldn't control rotation, so that is what C is for, but B would control Rotation depending on how you define it. I love trying to peer into the mind of the drafter. Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-68986 Share on other sites More sharing options...
[SH...] Posted January 26, 2021 Share Posted January 26, 2021 Datum B is a pattern? Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-68988 Share on other sites More sharing options...
[To...] Posted January 26, 2021 Author Share Posted January 26, 2021 The function of this part is to rotate into position about the A axis. 2 pins extend out from the main body of the mating part into the datum B holes to lock the part into position. Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-68990 Share on other sites More sharing options...
[To...] Posted January 26, 2021 Author Share Posted January 26, 2021 Please sign in to view this quote. Yes Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-68992 Share on other sites More sharing options...
[Ch...] Posted January 26, 2021 Share Posted January 26, 2021 I think it "could" be a valid tertiary. However with the 2x Datum B, I think it would be best to get designs intent input. this might be the first possible use I've seen for Calypo's new "Parallel Cylinder" feature for 2x Datum -B- ... Good luck. Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-68994 Share on other sites More sharing options...
[An...] Posted January 27, 2021 Share Posted January 27, 2021 _ Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-68996 Share on other sites More sharing options...
[To...] Posted January 27, 2021 Author Share Posted January 27, 2021 Please sign in to view this quote. Andreas, Thank you for your sketch. Understanding a bit more of the function of this part, I'm quite sure the designer was intending to define the part as you have shown on the left sketch. But in ASME, if a feature can control a degree of freedom, it must control a degree of freedom, so the symmetry of the 2 B features controls the location along the A axis and controls rotation about the A axis. My customer is not the end customer, so communication with the designer or quality people is not something I can control. I have to work to the standard unless my customer instructs me to do otherwise. I'm not sure my customer understood the DRF when they accepted the job. Plus, the parts are already made so no corrections can be made. I just want my customer to be armed with the correct information if they get into a discrepancy discussion with their customer. Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-68998 Share on other sites More sharing options...
[To...] Posted January 27, 2021 Author Share Posted January 27, 2021 See BelowHole Pattern Identified as Datum.jpg Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69000 Share on other sites More sharing options...
[An...] Posted January 27, 2021 Share Posted January 27, 2021 _ Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69002 Share on other sites More sharing options...
[Cl...] Posted January 27, 2021 Share Posted January 27, 2021 Does this indicate that -B- acts as both secondary and tertiary? Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69004 Share on other sites More sharing options...
[Ri...] Posted January 27, 2021 Share Posted January 27, 2021 Please sign in to view this quote. That is the typical understanding. If you just selected features inside of Calypso inside of the Alignment/DRF, Calypso would follow the can-may-must rule, and all 6 degrees of freedom would be constrained after A & B. You would have to create an alignment that forces the Planar Rotation to be C if you didn't want B to control the rotation around the primary. Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69006 Share on other sites More sharing options...
[To...] Posted January 27, 2021 Author Share Posted January 27, 2021 Please sign in to view this quote. Screenshot 2021-01-27 120123.jpg Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69008 Share on other sites More sharing options...
[An...] Posted January 27, 2021 Share Posted January 27, 2021 _ Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69010 Share on other sites More sharing options...
[To...] Posted January 27, 2021 Author Share Posted January 27, 2021 Ok. For clarity, there is no MMB on DRF ABC though there probably should be.Screenshot 2021-01-27 131354.jpg Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69012 Share on other sites More sharing options...
[An...] Posted January 27, 2021 Share Posted January 27, 2021 _ Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69014 Share on other sites More sharing options...
[To...] Posted January 27, 2021 Author Share Posted January 27, 2021 Please sign in to view this quote. Try to imagine the function of this part is to rotate into position about the A axis. At this final position, 2 pins from the mating part will extend into the holes to lock the rotation. Datum C cannot add anything else to the function . Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69016 Share on other sites More sharing options...
[An...] Posted January 28, 2021 Share Posted January 28, 2021 _ Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69018 Share on other sites More sharing options...
[An...] Posted January 28, 2021 Share Posted January 28, 2021 _ Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69020 Share on other sites More sharing options...
[Ri...] Posted January 28, 2021 Share Posted January 28, 2021 Please sign in to view this quote. My favorite is when I see this callout, and there isn't even a datum structure on the drawing. Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69022 Share on other sites More sharing options...
[To...] Posted January 28, 2021 Author Share Posted January 28, 2021 Please sign in to view this quote. Technically, my original post stated my interpretation of the drawing. I asked for responses that offered different interpretations, along with documentation to support the alternative interpretation. My expectation was to get interpretations based on actual standards. Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69024 Share on other sites More sharing options...
[An...] Posted January 29, 2021 Share Posted January 29, 2021 _ Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69026 Share on other sites More sharing options...
[SH...] Posted January 29, 2021 Share Posted January 29, 2021 Please sign in to view this quote. I want your autograph.. 🙂 🙂 Link to comment https://qualityforum.zeiss.com/topic/13492-profile-datum-structure/#findComment-69028 Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in