Another ASME profile question Ugh!

Does the print specify a year for ASME Y14.5? The definition was changed to the single value method (twice the largest deviation) in the Y14.5.1 - 2019 math standard which applies to Y14.5 - 2009 onwards. 2020 R2 was the first version of PC-DMIS to implement that change with the introduction of the geometric tolerance command.

If you still need the older, two value method (max & min) you can use legacy profile.

yes, it's 2009. Thanks for the quick response. Looks like double the max it is.

Don't use PC-DMIS ASME profile, using feature control frame characteristics. The software outputs the wrong value, and the precise flavor of wrong changes with every other release. Note that I I can't swear that it was never correct in any version, having not dug into every single service pack.

IF you want to use FCF profile in PC-DMIS, switching to ISO within the software, did calculate correct ASME values, at least in PC-DMIS 2016-2019.

The best sure-fire method to calculate profile correctly in ALL versions of PC-DMIS is to set alignment appropriately, measure a set of points, report "T" values, and sort, either via variables in PC-DMIS, or export to excel and calculate profile in that program. That way there's no confusion between versions, and latest undocumented enhancements within PC-DMIS.

I commonly do individual points since I like to see where the problems are coming from exactly. But this company in particular would throw a fit if they see ISO on the pdf report. Regardless of the output. And for that matter, the output is the same. We have a meeting with them today so I can explain why they would want individual points. They can easily take the worst deviated point and double it themselves.

Kai Kendall I take exception to your statement that "the software outputs the wrong value".

As I said in my previous statement, the ASME Y14.5.1 math standard defines the way in which profile is calculated. Feature control frame reporting (XactMeasure) up until 2020 R1 followed the rules and calculation method detailed in ASME Y14.5.1 - 1994 which stated that BOTH the max and min deviations must be compared to the tolerance in order to verify conformance.



The next release of the math standard (14.5.1 - 2019) was published in early 2020. Again, as I said, the definition changed to a single value method - twice the largest deviation - and the geometric tolerance command in PC-DMIS 2020 R2 onwards supports this.

I checked with Hexagons Dimensional Standards Compliance Manager (Robert Jensen) who is also a member of ASME and ISO and whom chairs the ASME Y14.5.1 math committee and he confirms these facts.

Safest way would be to collect T values of a bunch of points, but "OUTPUT=NONE" in the characteristics, then maybe use variables to force PC-DMIS to calculate profile correctly (2x the maximum absolute deviation of all the T values).

If you use FCF dimensions, you will be opening yourself up for a world of grief, because the reported values will be different (and usually wrong) with nearly every version of PC-DMIS.

Please refer to my previous comment.

I'm not one to push buttons on pcdmis and hope I'm getting the right figures. I like to know how stuff works. With that said I've created my own alignments, reported out the deviations then ran the Geotol FCF and both came out with the same deviation. It seems to work fine for my needs. Kai, I'm not sure what problems you are having or how you can explain them better to Neil.

Sounds a bit like an unsubstantiated Geoffism there Kai! Details and examples please?