How to report Envelope

[[Za...]]

Have a circled E on my print, after researching i understand they are wanting the envelope of the diameter. Everything online says to make sure the diameter fits with in the MMC. My thoughts on that are reporting maximum inscribed element evaluation. Am I correct or is there a better way to do this? Thanks everyone.

[[Mi...]]

If it's a bore yes Maximum Inscribed would work

There is also the special 2 point diameter characteristic that can do a few things, but one of them is an option for Envelope

[[Ri...]]

This is most likely an ISO drawing as ASME is implied as always an Envelope Condition unless states with the Independency Condition.

As long as you are scanning a full circle, use the 2-Point Diameter Characteristic because Envelope measures both the MMC (Max Inscribed on an internal feature and the Minimum Circumscribed on an external feature) as well as the local 2-Point measurements.

https://www.gdandtbasics.com/envelope_requirement/

[[Je...]]

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When I wish to report per the envelope principle in Calypso, I use "Outer Tangential Element" as the evaluation method. This defaults to the maximum inscribed element for an internal feature of size and the minimum circumscribed element for an external feature of size.

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Here's a jazzy little document that nerds out on evaluation methods in Calypso:

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[[Ab...]]

https://portal.zeiss.com/knowledge-base?id=1542831

[[Za...]]

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Thank you sir, I found the envelope option on the 2 point diameter.

[[Za...]]

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Thanks for that piece of information!

[[Cl...]]

Nothing to add really. Just an observation about only ever seeing this callout
when I was working in aerospace. Never seen by me in automotive or medical.
Always wondered the reason for that.

[[Ri...]]

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It should only ever be seen on an ISO drawing, so typically anything non-American, and then it's just going to depend on the functionality.

If it's American, technically per ASME it is always implied Envelope Condition, but just because an Engineer put "INTERPRET GEOMETRIC TOLERANCE PER: ASMEY14M-2009" doesn't mean they actually want you to inspect it that way, or even actually understands what the ASME standard is. A lot of my aerospace customers are moving to be fully compliant with ASME. I have some medical customers that do want you to comply with the standard as well.

As for automotive, it's the wild-wild-west sometimes with those guys, and it also just depends on the customer/application. I've seen some applications where they explicitly callout that both the Max Inscribed and the Min Circumscribed has to be within the diameter specification.

[[Ch...]]

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I love arguing with people who say they understand GDT but don't know about the envelope principle. I'm like 'they literally call it rule number 1 dude'