Gap in a feature of size

[aniiben]

I have a faucet plastic component which has gaps/ interruptions along the circumference of an outside diameter. I cannot share the entire part, but something which is very similar is shown below. The outside diameter has 8 gaps around the 360° degrees which creates 8 arcs.
How can I define those 8 arcs related with a datum reference frame ?
I am using ASME 2009 (or with a note I can use 2018). I know I can use profile and position, but my question is:
Can I use CF- continuous feature per 2009 or 2018 with position ?
Can I use 8X size (.500±.015) and position?
(Profile and phantom circle is not much liked in my general industry- hence I will leave it to the last resort )

 

[3DDave]

Your question is best asked of your inspectors.

In the example you are pointing at the edge between two nominally contiguous features.

Without CF individual sub-arcs won't really be features of size, so that's the only option.

I would be more likely to use total runout than position for an item like is pictured, but probably the real part is not like the picture, for simplification purposes.

 

[aniiben]

Your question is best asked of your inspectors.

In the example you are pointing at the edge between two nominally contiguous features.

Without CF individual sub-arcs won't really be features of size, so that's the only option.

I would be more likely to use total runout than position for an item like is pictured, but probably the real part is not like the picture, for simplification purposes.

3DDave,

Runout option has been explored before, but since this feature it is not easy accessible (nor can rotate due to other features involved) this runout option fall by the wayside.
So which option would you prefer:

CF + position on the phantom circle
OR
8x .500±.015 + 8x position to main datum reference frame
OR
8x .500±.015 + position on the phantom circle

 

[3DDave]

Frankly it sounds like you are hostage to your own QA and need to ask them. I don't prefer any of those options because I expect it has nothing to do with part function. It's like asking what speed a car should go, but neglecting to say on what road, race track, or drag strip. I'm sure the actual function and the way the tolerances are to be allocated across all the parts is a corporate secret, so I won't be able to help you there.

 

[aniiben]

Frankly it sounds like you are hostage to your own QA and need to ask them. I don't prefer any of those options because I expect it has nothing to do with part function. It's like asking what speed a car should go, but neglecting to say on what road, race track, or drag strip. I'm sure the actual function and the way the tolerances are to be allocated across all the parts is a corporate secret, so I won't be able to help you there.

I am confident that the actual function, design intent and the datum reference frame are adequately covered. The question I have, at this time, is how to define in ASME the pattern of those arcs? What would be the best / standardized method?

 

[3DDave]

The best one may be CF. You want to explicity define the separate surfaces as a single feature.

You already know that. But if your QA doesn't like it, you will just choose something else.

Ask you QA group what they would do differently for each of the three methods.

All of those methods are standardized. Some are more explicit. 8X arcs is problematic as finding individual centers of small arcs is problematic.