MMR requirement - hole

[[Pe...]]

Hello everyone,

could someone please explain the difference between an extracted surface and an associated element in an MMR condition?

I’m trying to apply an MMR condition to a cylindrical hole, but I’m not sure which option I should choose.

It would also be great if you could show how you create it yourselves.

Thank you very much for any opinions and help.

[[Mi...]]

Hello, 
           I would start with the tech guide on position checks, if you have not already done so. 

https://techguide.zeiss.com/en/zeiss-inspect-2026/article/cmd_inspection_check_position.html

Tolerated element

You can choose whether you want to use an Extracted surface or an Associated element.

•  Extracted surface
  If you use this option, the software computes the material requirement based on the envelope of the element.
•  Associated element
  If you use this option, the software computes the material requirement based on the derived element, for example:
  • Center axis
  • Center plane
  • Center line
  • Center point

This option enables you to use bonus tolerances. In the bonus tolerance concept, parts of dimensional tolerances that are not used are applied as a bonus. The computation of the bonus tolerance is a method used in the ASME standard. Using bonus tolerances therefore does not conform to the ISO standard. To get results that conform to the standard, you must choose ASME Y14.5 in the drop-down list under Standard.

 

[[Pe...]]

Hello Mike,

thank you for sending the tech guide. However, I couldn't find all the information I was looking for. I wanted to ask if you could provide some additional details, as I couldn't find some of the information in the standard either, and I'm starting to get a bit lost.

Specifically, I'm interested in the ISO standard, as I don't work with ASME. If I want to enable the MMR condition, do I need to create a cylindrical hole using either the envelope requirement or the independency principle?

Also, should I be using the extracted surface or the associated element? If I use the associated element, does that mean I have to switch from ISO to ASME?

Thank you for your response,

P. 

[[Ma...]]

According to AI for ISO you should use Associated element.

But i agree there is not much of description what to use and what it's doing.

https://www.gdandtbasics.com/iso-vs-asme-position-tolerance/

Edited 4 hours ago

[[Pe...]]

Thank you for the link, Martin. Based on the video, it seems that the ISO approach is to use the extracted surface.

However, when I create a cylinder using either the envelope principle or the independency principle, the cylinder still has to be within a certain tolerance. Does this apply to both envelope calculation methods? That doesn't really make sense to me.

Could you please help me understand this as well?

Thank you.

[[Ma...]]

I am not sure your question.

For a Cylinder with (E) - i think for ISO it should be envelope diameter for outside and LP for inner side. On your screenshot you have both tolerances evalated as tangential element.

The most logical would be that your tolerance bonus would come from inscribed diameter, since it's the biggest diameter of a pin which can go through ( on your measurement 15,845 ).

[[Na...]]

Hi Peter,

please also have a look at this article about MMR: ZEISS Quality Tech Guide

With MMR you are analysing an assembly situation, so if the Diameter is out of tolerance, it will simply not fit - there is no "additional tolerance" left for the position -> it's calculated. If nothing else is displayed on the drawing, linear size with min/max local size would be the standard.

ISO uses the extracted surface. If you are interested, you can create the check with high tolerances, so you can create and calculate it and switch between extracted surface and associated element to see the difference in the tolerance zone (make sure to show the tolerance/virtual condition in the properties of the positional check).

There is an AUKOM GD&T training available. We also offer an Inspect specific GD&T training. This is more about the use of the software, for basics I would recommend the AUKOM training and soon there will be an introduction training for technical drawings. But for GD&T basics I think AUKOM is most suitable.

 

Nanno