This might be hard to explain without showing a print. Wish I could, but that's a no-no since they're confidential documents and all. Anyway, let's say I have an older print with holes that are dimensioned to each other, rather than to a datum or to a common origin point. They also have a true position call out. As I understand it, you can select either "current alignment" or "datum reference frame" when creating a position dimension for the holes. If I was required to report the holes with the nominal dimensions from the print, rather than from the datum reference frame, say for PPAP purposes, does that mean I would have to create an alignment for every single hole to get them to report exactly as the print dimensions them? Or is there a more efficient way to do that? I hope I'm making sense. I'm still pretty new to this.
without a napkin sketch, we can only help so much.
so you've got a pattern of holes, and some holes are defined as datums.
-Measure each datum hole.
-Construct an alignment for each feature control frame as you mentioned (AB, ABC or BAC),. and within each of the currently set alignments, measure & dimension output the specific holes that apply to that FCF.
--in my opinion if the pattern of holes is clear (like 12 holes about a set diameter, equidistant 30° spacing kind of pattern)... I would in addition to above, create a bestfit alignment to the 12 holes as a pattern, and check each hole's pass/fail result to the ABC FCF tolerance. it's probably a mount flange of some type and you'd be checking for functional fit this way, much better than the print calls out.
without a napkin sketch, we can only help so much.
so you've got a pattern of holes, and some holes are defined as datums.
-Measure each datum hole.
-Construct an alignment for each feature control frame as you mentioned (AB, ABC or BAC),. and within each of the currently set alignments, measure & dimension output the specific holes that apply to that FCF.
--in my opinion if the pattern of holes is clear (like 12 holes about a set diameter, equidistant 30° spacing kind of pattern)... I would in addition to above, create a bestfit alignment to the 12 holes as a pattern, and check each hole's pass/fail result to the ABC FCF tolerance. it's probably a mount flange of some type and you'd be checking for functional fit this way, much better than the print calls out.
