2023 applying spherical MMC Bonus to a circular tolerance zone

[[Ti...]]

I'm testing 2023 and it looks like you cannot use MMC from a sphere with a circular tolerance zone. I'm I correct that you cannot use MMC of a sphere with a circular tolerance zone?

 

It would be nice to be able to do this, b/c the only other option is to create a circle in order to get MMC but as we all know a circle is not going to properly get the 3d geometric diameter of the feature.  Currently, I am applying spherical bonus using a formula inside the user defined checks with 2021. 

 

 

[[Lu...]]

Hi Tim,

it is not possible to check a cylindrical tolerance zone for MMC on a sphere. As you have already written, you would have to create a circle.

I'm just curious, but why don't you use a spherical tolerance zone?

Best regards

Lukas

Edited April 2

[[Ti...]]

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Two reasons why I don't use spherical.... First, there are two independent callouts for position of the sphere. The first one asks for spherical with all degrees of freedom constrained so it is asking for the Z deviation as well as the X and Y.  The tighter tolerance of 30 microns asks for only X and Y and releases the Z requirement so I don't want to measure spherically bc it will make the measured value larger than it needs to be. The problem is I cannot apply spherically measured diameter bonus to a circular(only X and Y) position check.  Also, some of our prints have a plus minus dimension on the sphere and then only a XY positional check, so adding the Z component only increases failure rates.

 

While I understand the reason behind this, it makes a lot of sense to add this ability in the software. In 2021 we couldn't use sphercial bonus, I was told in 2023 we can, but I just found out only if you are measuring position in all axis. Just becomes a hassle to create more outputs manually using the user defined checks and creating a check where the larger the value the better, which my machinists didn't understand at first. My check is basically this equation.....     Stated tolerance + Bonus - (Deviation *2)   So the larger that value the better, which is opposite a normal position check. I apply a comment to the report letting them know this is happening.

Edited April 3