Surface Profile with Position of point? (ISO GPS) 1

[Brokenengineer]

Dear all,


I am trying to control the main outside profile of this part but hold the end feature to a tighter tolerance.
See attached:

https://files.engineering.com/getfile.aspx?folder=5c5a3e36-e738-49ba-9716-020dfa4d601b&file=gdt1.png

Is this an acceptable use of the surface profile call out with a specific feature using the size/TP call out?
I am working on BS8888 - ISO GPS, and provide 3D CAD models to our supplier.

This part rotates on the 5mm hole and is intended to locate another part preciecly on the 2mm nub.

Additionally, would this be an achievable tolerance of a part on a CNC machine?

Thanks!

 

[greenimi]

Just to clarify:
I think position can be used as refinement of the all around profile. Again, I think is clear. However I am not sure if it is legal, but I think so.

My previous issues (copy-paste below) is about collection plane indicator and its mandatory usage. I think you have to use it per the latest ISO standards.



The question I have is: do you have to use collection plane indicator?

Per ISO1101/2017 paragraph 16.1
Collection planes shall be used when the “all around” symbol is applied. The collection plane identifies a family of parallel planes, which identifies the features covered by the “all around” indication.

Per paragraph 9 we can read:
If a geometrical specification is applied to the outlines of the cross-sections or if it is applied to all features represented by a closed outline, it shall be indicated by the symbol “all around” placed on the intersection of the leader line and the reference line of the tolerance indicator (see examples Figure 51 and 53). A collection plane indicator shall be used to identify the collection plane in 3D and is preferred in 2D. For deprecated 2D practice, see A.2.3. An all around requirement applies only to the surfaces identified by the collection plane, not to the entire workpiece (see Figure 52 and 54).

 

[greenimi]

Anyone else?
Any other opinions?

 

[Brokenengineer]

Thanks Greenimi,

Thanks for pointing out the requirement of collection planes! I thought it was somewhat implied from the view, but I see it must be defined.
And on second thoughts I think the Line Pofile may be a sufficient call out for my application.
Is there a way to define at which hieght the line profile should be taken, or our multiple highets usually taken?

If anyone else can confirm the legality of using true position for refining the surface profile that would be great.

Best

 

[greenimi]

And on second thoughts I think the Line Pofile may be a sufficient call out for my application.

I would use surface profile and not line profile

Regarding you second question, I would say that by line profile definition you have to take each and every height, but there is "no connection" between those measurements (no simultaneous requirement since you don't have a complete datum system |A|B|C| and also you don't have CZ or SIM's indicators)

On a different thread pmarc said "would be no difference between line profile and surface profile in the |A|B|C| case."

https://www.eng-tips.com/viewthread.cfm?qid=491974

pmarc,

Am I on the right track here? What do you think?