Profile of a surface tolerance

[Bogdan.]

Hello guys,

I have a question, how can be interpreted the value "+" from profile of a surface from this image.

Thank you !!

 

[Wuzhee]

My guess would be unilateral profile that adds material between C and D.
But the amount is unknown or specified elswhere (could be in the generic title block callout)

What is UF and SIM?

 

[greenimi]

This is an ISO spec.
I think ISO1101:2017 could be helpful to decode this requirement however it is missing the tolerance zones (both of them) and the UZ modifier...I think
Again, incomplete (wrong grammar) per ISO GPS

The correct syntax is: geometric tol| xxx UZ +or - YYY| datum system|

xxx and YYY being tolerance zones values

 

[greenimi]

UF = united feature
SIM= Simultaneous requirement with other tolerance indicator

 

[pmarc]

Is there a chance that somewhere on the face of the drawing there is a note or a block in which the + sign is associated with a value?

 

[greenimi]

Is there a chance that somewhere on the face of the drawing there is a note or a block in which the + sign is associated with a value?

pmarc,
And if there is, would you say that is a correct approach per ISO GPS standards--without using UZ modifier?
(let's say + = .010 inches)

 

[pmarc]

greenimi,
I wasn't thinking about the UZ really. Maybe the '+' is used similarly to a reference letter, like A or B, and the tolerance value is defined somewhere else on the face of the drawing.

 

[Bogdan.]

There is no "+" in the drawing or in the title block to take the value.
Maybe does it mean that in this area always it's needed to have a positive tolerance?

 

[3DDave]

No comment.

 

[Bogdan.]

I found in ISO 1101 this information, the “+” sign can be in correlation with rugosity from the drawing?

 

[Burunduk]

Bogdan,
A '+' symbol alone is not the standardized way to indicate unilateral outside tolerance zone.
In ISO, it would be UZ modifier being used. If for example the tolerance is 0.2, the tolerance compartment would say 0.2 UZ +0.2, meaning the entire tolerance is outside the material. But a tolerance value is needed anyway for the requirement to be meaningful.

Also, what does datum reference C-C mean.
If a datum is established from two features, it would be B-C or something similar.

Maybe it's made to some internal standard? Very odd.

 

[greenimi]

Also, what does datum reference C-C mean.

C-C is the way ISO shows the feature's pattern ( see ISO5459:2011, also maybe ISO5458 and ISO1101)

 

[greenimi]

I found in ISO 1101 this information, the “+” sign can be in correlation with rugosity from the drawing?

Nope. The + sign is from the tolerance indicator requirement ---- NOT from surface finish per the ISO books.
But your designer did not read and understand the requirements clearly specified in your attached picture from your post on 14 Sept 22, at 09:21.
That picture and the applicable text clearly shows how to specify the tolerance zones

 

[greenimi]

If for example the tolerance is 0.2, the tolerance compartment would say 0.2 UZ +0.2, meaning the entire tolerance is outside the material.

Are you sure about that?

 

[Belanger]

Burunduk, a quick correction... When using UZ, the first number is the total tolerance amount, but the number after the UZ indicates where the center of the tolerance zone is.

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

 

[greenimi]

a quick correction... When using UZ, the first number is the total tolerance amount, but the number after the UZ indicates where the center of the tolerance zone is.

J-P,
That's exactly where I am getting to.....Looks like ISO GPS is not his/her forte.........it is not mine either, for that mattter.

 

[Burunduk]

Belanger and greenimi,
Thanks for the correction.
I should have written 0.2 UZ +0.1 to describe the requirement of a unilateral outside, 0.2 mm zone.
Correct this time?

 

[Belanger]

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