[Do...] Posted January 5, 2024 Share Posted January 5, 2024 I have an application where I have datum A (plane), datum B (center point of a hole) and then datum C (center point of another hole). My callout for datum C is 10±0.2mm diameter with a true pos. of 1.5(MMC)|A|B|. How do I properly check the true position of datum C in order to quality it back to A & B? How is this done before setting up the part alignment that is constrained by all three datums together? Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/ Share on other sites More sharing options...
[Ma...] Posted January 5, 2024 Share Posted January 5, 2024 I would make new alignment and put there A and B ( primary, secondary ) and fill XYZ by them. I assume C is used for stoping rotation. Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/#findComment-17234 Share on other sites More sharing options...
[To...] Posted January 5, 2024 Share Posted January 5, 2024 Please sign in to view this quote. Create a Position Characteristic (Position1). Convert it to a Best Fit Bore Pattern. Add Datum A and Datum B. Add your tolerance. Click Bore Pattern button. Click Select Elements button. Select Datum C feature. Click OK. In Best Fit section, un-check Translation checkbox. Select View Tolerance (with MMC/LMC of the references) Optional: Rename Best Fit1 (at top) to ABC. Click OK. Click OK to close Position window. For characteristics that reference ABC, i.e. Position2, Select ABC from Datum reference frame dropdown menu, as shown below.Screenshot 2024-01-05 095357.jpgScreenshot 2024-01-05 095048.jpg Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/#findComment-17236 Share on other sites More sharing options...
[Do...] Posted January 5, 2024 Author Share Posted January 5, 2024 What if datum C & B are not in line with each other as far as Y, Z goes? Will your example for (Position1) still apply? My coordinates for C from datum B are 280.4 mm in "X", -118.7 mm in "Z" and C lies on a plane that is 587.2 mm in the "Y" axis. Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/#findComment-17238 Share on other sites More sharing options...
[To...] Posted January 6, 2024 Share Posted January 6, 2024 Please sign in to view this quote. Any chance you can create a sketch of your datum features? Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/#findComment-17240 Share on other sites More sharing options...
[Ri...] Posted January 6, 2024 Share Posted January 6, 2024 Please sign in to view this quote. I assume they drew all of the basic dimension off of the X/Y/Z Coordinate System, and they didn't make it where Datum C is inline with one of them. Like below. If this is the case, you will still use Datum C as the Tertiary, but you will need to use the Rotate by distances (unless you want to work the Trig out yourself) function to square the Coordinate System back up to match the drawing. Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/#findComment-17242 Share on other sites More sharing options...
[Do...] Posted August 13, 2024 Author Share Posted August 13, 2024 Please sign in to view this quote. How do I then check the position of my tertiary datum to AB? Do I then use the method described above by Tom Oakes? Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/#findComment-17244 Share on other sites More sharing options...
[To...] Posted August 14, 2024 Share Posted August 14, 2024 Please sign in to view this quote. My initial response would be YES, but that may be a little biased...lol Are you having an issue with the instructions in my post? Are you stuck? Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/#findComment-17246 Share on other sites More sharing options...
[Do...] Posted August 14, 2024 Author Share Posted August 14, 2024 Please sign in to view this quote. No, I understand your instructions. I just wasn't sure if it only applied if the tertiary datum was in-line with the secondary. Or if it would apply if my tertiary was offset to the secondary, but only after I have corrected my WCS as described by Richard Shomaker. Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/#findComment-17248 Share on other sites More sharing options...
[To...] Posted August 14, 2024 Share Posted August 14, 2024 Please sign in to view this quote. My bad. Yes, follow Richard's post for the base alignment. Link to comment https://qualityforum.zeiss.com/topic/5094-true-position-of-tertiary-datum/#findComment-17250 Share on other sites More sharing options...
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