GD&T: Material Requirements

[[Ri...]]

Please, please, please stop this behaviour. 

 

[[Ra...]]

Hello, 

Please share this request to the My Voice portal. 

https://portal.zeiss.com/my-voice/software/metrology

[[Ri...]]

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I have requested multiple things for Inspect, but I do not see any feedback from Zeiss. 

These were posted all the way back in 2024. 

https://portal.zeiss.com/my-voice/software/metrology/product/eaafdea8-9296-485d-82c1-cc6d1ca0eca2/request/c3051e15-87d9-436b-a489-1b142d7d6559

https://portal.zeiss.com/my-voice/software/metrology/product/eaafdea8-9296-485d-82c1-cc6d1ca0eca2/request/f0335067-2822-4b52-8912-fd2c2f43d696

[[Ri...]]

And to add to the confusion: what exactly is out?????????

 

[[Ch...]]

Regarding your last post.

The linear size check do not measured the virtual condition, due to the fact

* for datum B your linear size check do ignore the perpendicular constraint to datum A

* for datum C your linear size check do ignore the perpendicular constraint to datum A and the distance constraint to datum B

We are quite sure that we compute the virtual condition quite exact but if your sure that there is really a computation mistake please contact your local support contact.

 

Regarding your first post:

Due to the fact that MMR computation is the simulation of a gauge, you have to check if it possible to put a virtual gauge (based on your nominal sizes) into your drills (or bolts). If this failed the error message appears. We don't see how it should possible to provide a standard conform datum system without this check (and the error message if this check is failed).

Of course, we could and should think about more user feedback what exactly is going wrong. This is already on our list for further improvements.

[[TI...]]

We cannot use MMR on datums due to this virtual condition being violated error. 

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 when I have time I will carefully go thru this error and send zeiss an email, b/c I understand what you are saying, but I don't think something is correct.

Now, there is another real issue that needs to be fixed regarding MMR on datums in Zeiss Inspect and that is that all subsequent datums must have MMR used.  Even if the last datum is a plane like you would place the part on a surface plate. You cannot have MMR on a surface plate.

 

 

[[TI...]]

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  Let's spitball this for a second.  Let's take the image above as an example.  Datum A MMR is 35.1mm. So as long as that Datum Cylinder is machined below 35.1 at all cross sections(local size) there should be no violation bc you would be able to fit that datum Cylinder into a gauge machined at 35.1mm and rattle it around to help the cross thru hole positional check.

 

Now let's assume that Datum A is LMR so its virtual size is 34.9mm. You cannot do gauging for LMR, but it is a legit usage of datum material requirments so you cannot build any type of gauge for this.  I'm not sure how the software is going to behave with LMR, but I will try it out later when I have time.  It may just not allow you to use it if the whole concept inside the software is hard guaging theory.

[[TI...]]

let me add that the virtual pin that would be used to gage the thru hole would need not to be violated at 7.7 in diameter and related on center to Datum A....but considering Datum A can rattle around in its hard gage.

These are the issue I will be carefully creating a video on. We have some extremely accurate CT scans of parts where all features are at nominal and there should be no virtual errors on feature callouts plus the datum MMR creation.

[[TI...]]

Last thing I'd like to say on this topic before I do some investigation on our parts.......

 

The software should 100% allow the datum system to be created and report some type of measured value EVEN if it thinks the measured value is way wrong due to hard gaging theory.  At least this way we get a 'measured value' that we can see and investigate....instead when we get this error the software reports ???????????.

 

And let me further state that this shouldn't be on the customer to open an internet ticket to get resolved, this is a known issue as I have a 2 yr old ticket that has long been closed regarding this.  I have so many tickets opened I've lost count, but I still feel the software is awesome and a remarkable piece of work.

 

 

Edited 9 hours ago

[[TI...]]

I just opened a ticket with Zeiss on this issue:

 

 

[[Ch...]]

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In my opinion, if you like to simulate that you put the part on a surface plate then this plane should be the first datum. But nevertheless we could solve this problem for some cases. Therefore please check with ZEISS Inspect 2027 (when its released) if your problem is resolved and this error message is gone for good. Feedback on this matter is highly appreciated, so that we think about the next cases to be solved. 

[[Ch...]]

My argument that MMR/LMR is the simulation of a gauge I have only said to make clear what the motivation for a datum system under material requirements is. Of course this is only an illustration what is going on. But if you like the explanation the same result please have an look into the standard. See ASME Y14.5.1-2019 (only for planes, for width elements you have a similar definition there):

"4.7.5 Datum Features of Size Referenced at MMB

a) The candidate datum set of a cylinder is the set of axes of all datum feature simulator of MMB size that [enclose] {are enclosed within} the datum feature. For secondary or tertiary datum features, the simulators are constrained to be basically oriented and, if applicable, basically located to the higher precedence datum. [...]"

This is what the software test. And in your case is seems to be the problem that their exists no valid candidate datum set. Yes I admit it can be confusing that the error message uses ISO vocabulary (the definition for the ISO standard is the same but the have other names for similar concepts), maybe we should respect the chosen standard for error message text.