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DonSenchuk12-Amethyst
12-Amethyst
May 6, 2020
Question

ANSI 1982 Datums

  • May 6, 2020
  • 1 reply
  • 5608 views

We just upgraded to Creo 6 (from 3.0). All our legacy data was made with datum callouts per ANSI 1982. (Datum under dimension).

 

One of my users reports trouble changing a datum to show this way. The datum in question is showing per ASME 1994.

 

The properties window for datums used to have this as a radio button, but that's gone now.

 

I also know there was once a config option (.dtl I think, but maybe .pro) for how datums are displayed, but I cannot find this option now.

 

Does this option still exist? If so, what is it? How do we show datum callouts under dimensions now. (Aside from faking it with the @[-A-@] cheat.)

1 reply

B
23-Emerald III
BenLoosli23-Emerald III
23-Emerald III
May 6, 2020

The change was made in Creo4.

Asme Y14.5 for defining how datums are attached was revised in the 1994 spec. That spec is now 2 releases old as there have been a 2009 and a 2018 release. Not sure when PTC will support the 2018 spec in Creo, so we have only specified the 2009 release as being our standard.

 

I do have to ask the question: Why are you just now going to Creo6 when it is no longer supported since Creo7 is out? Creo4 and now Creo7 are the 'long-term' Creo installations, released every 3 years. The intermediate releases, Creo5 and Creo6, have a 1 year support window before being replaced with the next release.

 

 

D
DonSenchuk12-AmethystAuthor
12-Amethyst
May 20, 2020

Since my last reply, I've been giving the new method a go. I gotta say my impression so far is it's hot garbage.

 

Are there any tips or tricks that make this new method as easy as the old?

M
Mfridman16-Pearl
16-Pearl
September 15, 2020

Hi @DonSenchuk 

I have couple of suggestions that might help in some cases:

1. If all you want is to Display the datum in the old ANSI 1982 way without having it really behave like the old datums that you could have placed on non geometry (e.g. mid planes) you can try and use the below display option for DFS. this might be obvious and already known to you, but I will mention it anyway, just in case

Mfridman_0-1600184863089.png

 

2. Also in case that you revise the GD&T in a legacy drawing/model to work per the new datum rules, you might want to consider using the Legacy Datum Annotation Conversion tool:

Mfridman_1-1600185002787.png

 This tool will be a good guideline for users who wish to migrate their old set datums to the new DFS datums, while keeping properly the relation between the new datums and the gtols that were previously referencing them (and keeping them associated)

 

I hope that this will help

Michael

 

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