ISO question

[Kedu]

ISO GPS world

How the specification change IF position is used instead of shown profile for the angled surface?

I am trying to get the details of both specifications (profile versus position in ISO) and mainly the differences between them (if any).

 

[Belanger]

It would be exactly the same. In fact, the picture you give is very similar to the one shown in SAE's "Ultimate Pocket Guide -- ISO GPS."

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[Kedu]

the picture you give is very similar to the one shown in SAE's "Ultimate Pocket Guide -- ISO GPS."

In SAE material, is it shown with position or profile?

My basic confusion is:
I do not know when the position is applied to the median feature and when is applied to the integral feature or surface?
Could a planar surface "accept" both?

Should I understand that in this particular figure, only integral surface is applicable?

 

[Belanger]

Sorry -- the ISO guide I was referring to has the same part as your picture, but with position. It describes the tolerance zone in the same way that we would interpret profile (two parallel planes that control location, orientation, and also form/flatness).
This application of position does not deal with the "median" idea.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[greenimi]

J-P,
I am trying to learn ISO too: what would be the difference between extracted surface and integral surface?
How do I know that the profile (or position) is applied to the integral feature or the extracted feature ?

 

[Belanger]

According to ISO 1101, when position is used in the way given by the OP, the "extracted (actual) surface shall be contained between two parallel planes" spaced apart by the amount given in the tolerance frame.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[pmarc]

The picture below comes from already withdrawn ISO GPS standard (14460-1:1999), but I believe it should help to understand terminology:

Regarding Kedu's picture, J-P is correct by saying that position in this case wouldn't make any difference. In ISO position can be applied to derived features (when applied to features of size) or to nominally flat integral features (surfaces). This is different from Y14.5, where position can only be applied to features of size.

 

[greenimi]

pmarc,
Since ISO 14406-1 is withdrawn, do you know, by any chance, where did they move those picture? Which released (if any) ISO standard has now this explanation?

On the same token, I know ISO 8015: 1985 had a nice figure (2) where on a section view of a cylindrical surface showing maximum limit of size and maximum circularity deviation (lobed form).
For my life, I do not edit (KNOW) where this picture has been moved / which standard, because in ISO 8015 - 2011 is nowhere to be found.

Do you know, from the top of your head, where these good and instructive picture were moved. Hopefully, they were not just eliminated from the standards entirely.

 

[pmarc]

Since ISO 14406-1 is withdrawn, do you know, by any chance, where did they move those picture? Which released (if any) ISO standard has now this explanation?

ISO 17450-1:2011

On the same token, I know ISO 8015: 1985 had a nice figure (2) where on a section view of a cylindrical surface showing maximum limit of size and maximum circularity deviation (lobed form).
For my life, I do not edit (KNOW) where this picture has been moved / which standard, because in ISO 8015 - 2011 is nowhere to be found.

I don't see this figure in any of the active standards that I have access to.

 

[CheckerHater]

ISO 2768-2 has something very similar:

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[greenimi]

I read in one of the ISO training materials I got today that the size limits alone provide a roundness control equivalent to approx. 30% of the diameter.
Not sure that is entirely true but it is how it is shown.

Looks like different authors have very different interpretations about this "built-in" roundness and when we should and when we should not have a separate control for roundness/circularity.

 

[greenimi]

pmarc,

Do you know if in ISO is acceptable (legal) to have a general profile tolerance shown in a note?
Such as Unless Otherwise Specified UOS : profile within some tolerance to A primary, B secondary and C tertiary?

Thank you pmarc