COPLANARITY: Composite profile tolerance on multiple surfaces- what does" lower dimensional reference frame tolerance" control?

[km2021]

this is my first post, and greatly appreciate your help.
coplanarity question:
in the composite profile tolerance as specified above for multiple surfaces, what does the lower dimensional reference frame tolerance of 0.1 control
is it simultaneous control for all three surfaces or is it independent requirement for the three surfaces individually?
does the lower tolerance 0.1 mean = all three surfaces need to be COPLANAR with in the band of 0.1 relative to datum A ?

 

[Michael_M]

The way I have always described the second frame is "to itself". In this case, you can have a profile within .5 but all profiles have to be within .1 to each other.

 

[km2021]

so to clarify my question,
do all three surfaces need to be with in 0.1 simultaneously , meaning you draw a SINGLE straight line band of 0.1 ( two lines that are 0.1 apart) and all the three surfaces need to be with in that single band??

 

[Cari Spears]

Yes. All three surfaces must be within 0.1 to each other, then that 0.1 tolerance zone can "float" within the 0.5 tolerance zone to A/B/C.

 

[Cari Spears]

And, welcome to the cove!!

 

[cristiano]

.

@km2021 are the 3 controlled surfaces completely parallel to datum feature A?

Otherwise datums B and C are useless.

 

[Michael_M]

@km2021 are the 3 controlled surfaces completely parallel to datum feature A?

Otherwise datums B and C are useless.

In the above case, it is a profile of a surface so 3 datums are required (you can have 2 datums but it is fairly rare), there is no call out for parallelism as the profile of the surface (requirement) handles that.

 

[Paul F. Jackson]

The lower note refines orientation of all three surfaces simultaneously to [A] while permitting translation within the upper's tolerance. (All points of 3 surfaces contained between two planes parallel to [A] spaced 0.1 apart)

The upper note controls the location of all three surfaces simultaneously to [A]. (All points of 3 surfaces contained between two planes parallel to [A] spaced 0.5 apart, one 10.25 from [A] and the other 9.75 from [A].

Lower segments of all composite notes are limited to controlling rotational degrees-of-freedom of the pattern's tolerance zones to the Datum References. Additionally the lower segment refines the pattern's feature-to-feature tolerance zones for translation and rotation although no such feature-to-feature translation is possible in this example since the features are defined as co-planar.

The uppermost segment controls feature tolerance zones to all applicable degrees-of-freedom (translation and rotation) to the Datum References.

 

[cristiano]

.

Michael, where did you read this?

 

[Michael_M]

Michael, where did you read this?

I am not sure I understand your question.