Profile of Base pads

[[Za...]]

Does anyone know the correct evaluation method for this profile call out in Calypso? I know the Feature needs to be minimum feature, but since the profile is not called back to a datum I was told by a Zeiss applications engineer to call it back to itself for primary, secondary, and tertiary datums. That being said, do I change the evaluation method on those to minimum feature as well? Calypso automatically has them as Outer Tangential.

Thanks I appreciate any feedback

Profile of Base Pads.png

[[Za...]]

That is what it is now. But since we don't have free form I was told to call it back to itself 3 times which does the same thing. The issue I am having is do I keep them as OT or change them to Minimum Feature? The #'s are very different.

[[Cl...]]

I've not ever heard that answer given? If you choose "Clear Datum Reference Frame" from the
drop-down menu, I would expect to see no change in the result. If you then dropped that feature
into a Form characteristic, that should also show the same result. Just a way of double checking.

[[Cl...]]

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I don't have it in front of me but I believe the cook book states minimum
feature for the evaluation of the feature and OT for the datum features.

[[Ia...]]

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What would the difference be between clear vs no reference plane in Calypso? Only at my offline seat right now.

I can't find any information on clear reference plane.

[[Cl...]]

Funny, mine states "Clear". What version Calypso are you running? Is this a change from the last rev maybe?

[[Ia...]]

I'm pretty sure you only get the option for "No Datum Reference" when using freeform or curve. You don't get the option for other features. I believe "clear reference frame" is available on all features, but I have never used it.

But I'm using Calypso 2019

[[Me...]]

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Yes, or you can simply use the flatness characteristic as an alternate method.

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This is most likely because your system is setup to do so... Extras>>Settings>>Measurement>>Form Datum

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"Clear / Load / Save Datum Reference Frame" creates a shortcut that allows you to save the features used as datum references. Datum references on additional characteristics can be populated without having to click through each one.

[[Za...]]

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When changing the 3 below to minimum feature, I got the same number double checking with the form characteristic.

[[Cl...]]

What about in a flatness characteristic?

[[Za...]]

Also the same number.....

[[Me...]]

All three are correct.

[[Za...]]

What if the base pads were slanted but flat? Flatness would still be in but profile should be out, correct? Does Calypso treat form, flatness, and profile of a plane the same if not called back to a datum?

[[Ma...]]

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Form, flatness, and profile of a plane not referenced to a datum should all yield the same result. GD&T standards don't allow the flatness characteristic to be applied to multiple co-planar surfaces so profile without reference is typically used in place of flatness.

[[Me...]]

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Yes, but only if the profile characteristic is setup correctly.

Keep in mind that the profile characteristic requires a fully constrained DRF in order to compute a result (unless using a Free Form Surface). This is why you needed to define each datum reference within the characteristic. In your example, the only requirement needed to obtain the correct result is for the considered feature be used as the primary datum reference established with the Minimum Feature fit. The secondary and tertiary could be any other measured feature.

When using the same plane as all three datum references, Calypso ignores the secondary & tertiary datum features and inherits the remaining degrees of freedom from the base alignment.