PC-DMIS to Calypso Question

[[Ri...]]

Hi All,

I had a customer requesting to report something that their customer was previously getting from a PC-DMIS report. It was the deviation of the DRF (we assumed to the initial alignment)

If you look at the Default Printout, there is a Delta value difference of an Alignment to the Base Alignment, but not if you just build a DRF in the True Position/Profile characteristic.

Anyone with PC-DMIS experience, can you comment on what actually this deviation is? Is it the delta value from the initial alignment, or is it something completely different? Why would you ever report this?

Thanks.

[[Jo...]]

I use stats command to export xml file, and it has options to report all kinds of information including alignments. It could be that is a vestige and not meaningful except to the operator. Could you post a snippet of the Pc-Dmis report for that ?

[[Ri...]]

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I don't have a report. We went ahead and went with the Delta value that is shown in the Default Printout for Secondary Alignments to the Base Alignment. We will see if their customer will accept that.

[[Ja...]]

Richard,

My guess would be the "Datum Shift" section of the default PC-DMIS report. I have attached an image. Any time that you have unconstrained DOF, or datum features utilizing modifiers (and thus freeing up some DOF a small amount), the DRF will shift a bit in an attempt to optimize your result as it is allowed to do so per ASME Y14.5.

The only direct relation that I've seen in Calypso is when you are doing a best fit of a bore pattern - Calypso will tell you, within the bore pattern menu, how much translation/rotation is used to optimize the result.

Hope this helps some.

[[Ri...]]

That's interesting that it shows the Datum Shift. The Best-Fit inside of Calypso is only showing the feature shift.

[[Ja...]]

I personally do not think that Zeiss handles Datum Displacement very well. ASME Y14.5-2018 7.11.11 states "MMB or LMB modifiers applied to the datum feature reference allow the datum feature to shift/displace from the boundary established by the true geometric counterpart in an amount that is equal to..."

[[Ri...]]

I'm not certain I agree with any software that simulates Datum Shift.

To me, when it comes to Datum Shift, you really should lean on a functional gauge.

Just my 2 cents.

[[To...]]

Not sure this is relevant to this conversation but I was told that if the measurement passes without the need of a datum shift, Calypso won't do it. Datum shift would only take place if it was necessary.

[[Br...]]

The defult Piweb graphical report for a BF bore pattern gives the amount of shift. Somehow I'm sure you could get that data into a different format if you wanted to.