Creo Tolerance & GD&T Tips & Techniques Session Recording (East Coast)

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Check out this video on Creo Tolerance & GD&T from Sigmetrix and PTC Application Engineers!

Presenters:  Raphael Nascimento (Sigmetrix), Lino Tozzi (Technical Specialist, Fellow) and Ryan Butcher (Technical Specialist, Fellow)

To dive deeper into the subject, check out PTC University.

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Webcast Q&A

Question from Acacio:  When I have a plastic part, who has a draft?  How can I get the dimension in the middle of the draft?

Answer:  For complex surfaces, you'll need to define a datum point where the controlling dimension is being applied, unless you have a vertex available to choose.  Often though, such complex geometries aren't well analyzed by a 1D stackup tool.

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Webcast Q&A

Question from Anonymous:  Can EZTA/CETOL pull tolerances from a parametrically linked drawing or do you you need tolerances to be in the model as annotations?

Answer:  For EZTA and CETOL to be able to read tolerances from your design information, they must exist in the part model.  It's not a requirement, as you can define the dimensioning scheme and associated tolerances in both tools. but use of existing date requires it to be present in the part.

Question from Anonymous: I don't see Application Tab in my Creo.  How do I turn that tab on?

Answer:  You do need an assembly on the screen and you need the module.  It may be a floating module for your company.

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Webcast Q&A

Question from Bruce:  We only use Profile and Position tolerances.  However, I notice the "smart" tolerance GD&T function doesn't even allow Profile choice.

Answer:  GD&T Advisor absolutely allows the application of Profile.  What made you think it didn't?

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Webcast Q&A

Question from Chris:  Is the validate function in Creo 7?

Answer:  Yes, it's part of the GD&T Advisor + package.  It was first added to Creo 4 M040, I believe.

Question from Chris:   That loop extraction worked very, very nice.  Any tips for avoiding error conditions with mates?

Answer:  The most important thing to consider is to define your assembly constraints with Creo using functional, surface to surface relationships.  This often contradicts modeling best practices for fully constraining each part as it is added to the assembly in Creo, so we've also introduced a very simple loop definition as well.

Question from Chris:  That manual loop definition looks very cool.  What happens if in CAD, they don't quite touch when you pick pairs?

Answer:  You can pick those up manually and add that to the stack up.

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Webcast Q&A

Question from Clay:  Can the TP advisor be done on tapered holes?

Answer:  Yes, GD&T Advisor can help you apply correct GD&T to drafted features, including tapered holes.

Question from Clay:  Can models/assemblies created in older versions of the software analyze this data when converted to the newest version?  Or do these need to be created in the newest version?

Answer:  Annotations in older models are fully upward compatible.  However, if you want to validate the GD&T, you would need the Plus license.

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Webcast Q&A

Question from Rui:  What are the main differences among GD&T Advisor, CETOL and EZTA?

Answer:  GD&T Advisor is a wizard/checking tool for the creation of GD&T Callouts on your 3D model.  EZTA (EZtol) is for 1D Tolerance Stackups and CETOL is for 3D Tolerance Stackups.

Question from Rui:  I should create 3D model in Creo (as usual), then go to GD&T Advisor and define each geometric tolerance I need?

Answer:  I'm not quite sure how to interpret "should" in this short context.  It depends on what you're doing today, what gains you'd like to get from the software, etc.  If you want GD&T Advisor to help you create GD&T consistent with the standards, you'll need to apply it in the part model and then show it on the drawing.  EZTA can read this information, but it doesn't have to be there for you to use EZTA to do your tolerance stackups.

Question from Rui:  The next step is to define stackups in EZTA?  

Answer:  ....building upon previous question, EZTA (EZtol) would be the next step to help you understand what the tolerance values would be in each of your defined tolerances.

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Webcast Q&A

Question from Thomas:  We have the full CETOL 10x license.  What is the main difference of the full version vs the extension now in Creo?

Answer:  The PTC Creo EZ Tolerance Analysis tool is is for 1D Tolerance Stackups.  CETOL is mainly used for 2 or 3D Tolerance analysis.  By 1D analysis, we're describing the typical stackup analysis where all included dimensions act in the same direction and no angular variation is considered.  3D looks at all possible errors that can occur - translations and rotations in all directions.