[Ja...] Posted May 11, 2021 Share Posted May 11, 2021 I've gotten some pretty conflicting answers over the years about the best way to report profile to one datum in Calypso. So, what's the most commonly accepted or agreed upon way that you guys know of? Link to comment Share on other sites More sharing options...
[Cl...] Posted May 11, 2021 Share Posted May 11, 2021 I've seen recommendations from Zeiss apps engineers and some on the forum that you populate all three datum spaces of the characteristic with that single datum. Link to comment Share on other sites More sharing options...
[Ja...] Posted May 11, 2021 Author Share Posted May 11, 2021 Please sign in to view this quote. Thank you, Clarke! Link to comment Share on other sites More sharing options...
[To...] Posted May 11, 2021 Share Posted May 11, 2021 Please sign in to view this quote. I am not a fan of this. I don't recall the particular situation but I seem to recall this did not work as expected. I wish I had documented my findings. Fortunately, we have Free Form and Curves so that is always my go to. I believe there are ways to use secondary alignments, 3d best fits, geometry best fits, etc., to build an equivalent to a "less than fully constrained" datum reference frame, but since there would be quite a few variations, there's no "one simple rule" that I can state. Just have to work things out logically.... Link to comment Share on other sites More sharing options...
[Ma...] Posted May 11, 2021 Share Posted May 11, 2021 I've tried this with bestfit alignment and 1 or 3 datums. bestfit and 3 datums are same numbers - at least i had. For 1 datum it's not same number - so i wouldn't support this way. But it could work for basic elements like cylinders. Link to comment Share on other sites More sharing options...
[Cl...] Posted May 11, 2021 Share Posted May 11, 2021 I would try multiple methods, then (if possible) see which one correlates with an alternate measurement method. Link to comment Share on other sites More sharing options...
[Me...] Posted May 11, 2021 Share Posted May 11, 2021 Please sign in to view this quote. This is correct... The base alignment will be used to constrain the remaining degrees of freedom and you can end up with bogus numbers really quick. Link to comment Share on other sites More sharing options...
[Ro...] Posted May 11, 2021 Share Posted May 11, 2021 Please sign in to view this quote. Agreed. Alignments are your friend and easy to create. I know if I create an alignment and best fit according to the unconstrained degrees of freedom that I'm getting the correct results. Link to comment Share on other sites More sharing options...
[Ja...] Posted May 12, 2021 Author Share Posted May 12, 2021 So, what would be your solution to this otherwise easy callout? The top surface is |A| while the entire perimeter contour is profiled back to |A|. Any suggestions on alignment? Spatial and Z origin to |A| and nothing else? Link to comment Share on other sites More sharing options...
[Ma...] Posted May 12, 2021 Share Posted May 12, 2021 Well I tried 3 different approaches. 1. Just used base A in profile char. 2. Created new alignment with primary set to base A and created new alignment from curves: selected move XYZ rotate Y 3. Created new alignment with primary set to base A, used recalled points to another curve with setted alignment as newAlignment with base A and choosed bestfitting XYZ and Y 1. did 0.0982 2. did 0.0982 3. did 0.0975 I choosed Y because i have curve on Y plane. Link to comment Share on other sites More sharing options...
[Cl...] Posted May 12, 2021 Share Posted May 12, 2021 I was under the impression that you could only use the best-fit if the profile referenced no datums? Link to comment Share on other sites More sharing options...
[Ro...] Posted May 12, 2021 Share Posted May 12, 2021 Please sign in to view this quote. You're going to need to align the part somehow to gather data, and you're going to need nominals. Let's assume you can align it with spatial as the top Z plane (3 DOF), top edge as X rotation and Y origin (2 DOF), and left end as a point for X origin (1 DOF) and that you have a CAD model for nominals. One way is to section the part in Z and create a closed curve around the perimeter. Then best fit the curve based on the unconstrained DOF. Datum -A- constrains 3 DOF, 1 origin, and 2 rotational. So you allow the others to best fit. You can do that in the curve itself, create a BF alignment separately, etc. So X and Y would be allowed to translate, and Z would be allowed to rotate for the best fit. Then use that alignment in the profile characteristic to report the profile. There are a few different ways to do this. This is just one. Link to comment Share on other sites More sharing options...
[Ro...] Posted May 12, 2021 Share Posted May 12, 2021 Please sign in to view this quote. You can best fit any DOF that are unconstrained by the datum features. Link to comment Share on other sites More sharing options...
[Ja...] Posted May 13, 2021 Author Share Posted May 13, 2021 Please sign in to view this quote. Sadly, I don't have Curve - just barebones Calypso 2016. Link to comment Share on other sites More sharing options...
[Ma...] Posted May 13, 2021 Share Posted May 13, 2021 Well then use general surface and use only base A in primary in profile char. Edit: Well - general surface is not an option. Then curve and/or freeform should be bought. Link to comment Share on other sites More sharing options...
[Ro...] Posted May 14, 2021 Share Posted May 14, 2021 Please sign in to view this quote. Use space points and either a Geometry Best Fit or 3d Best Fit alignment. Same principle. Link to comment Share on other sites More sharing options...
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