Free State Requirement for a dim without a FCF? 1

[ModulusCT]

I have a part where the engineer wants two things:

1) Datum feature B @ .550 +.030 / -.010 shall be measured in the free state (Default according to .5-2009 I think)
2) All other features apply while the aforementioned feature is in the restrained state.

What's the best way to indicate this? I thought that a flag note stating that "UNLESS OTHERWISE SPECIFIED, ALL REQUIREMENTS
APPLY TO THE PART WHILE DIMENSION INDICATED IS IN THE RESTRAINED STATE" appended to the dimension that should be first qualified in the free state. How to indicate that this dim is to be verified in a free state though is uncertain... mainly because, like I said, all examples of free state symbols are used in a FCF. Please see the attached image and let me know what you think. Thanks!

I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE plants!!

 

[ewh]

I think that appending the dimension with the restrained state note would add confusion. I would either add an additional flag note stating "INDICATED DIMENSION TO BE MEASURED IN THE FREE STATE" or simply append the dimension with "FREE STATE".

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

 

[ModulusCT]

Please see the additional attachment for further clarification of the requirements I am to fill... Any suggestions are welcome.

Thank you ewh.

I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE plants!!

 

[ewh]

ASME Y14.100-2013 ¶4.27.6 (c) Flag notes are located with the general notes but apply only at specific areas or points on the drawing.
The problem with placing the flag note at the dimension is that it contadicts the purpose of the note, which is supposed to apply everywhere except at that dimension (which is why I suggested adding an additional flag note, specific to that dimension). Simply appending the dimension with "FREE STATE" (not in parenthesis, as it would not be reference) should suffice.

Other viewpoints welcome!


“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

 

[TheTick]

"PERHAPS?" Not a good word for an authoritative document. I would avoid specifying actual procedure.

Also, it may not be possible to fixture the flanges to the specified dimension. They are not going to magically float into position. They will bend and be at odd angles.

 

[CheckerHater]

1. UNLESS OTHERWISE SPECIFIED, REQUIREMENTS TO BE VERIFIED IN RESTRAINED CONDITION
2. (with flag symbol) THIS DIMENSION TO BE VERIFIED IN FREE STATE

 

[dgallup]

I'm with CH. Have a general note that unless otherwise stated all dimensions are in the restrained state. Have another note that the one dimension is measured in the free state. I have one drawing where that is included in the text below the dimension line.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[KENAT]

I assume 'RESTRAINED STATE' is defined elsewhere on the drawing? I think the standard gives an example of defining what constitutes restrained state.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[ewh]

I gotta work on my communication skills!

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

 

[CheckerHater]

I assume 'RESTRAINED STATE' is defined elsewhere on the drawing?

According to ASME Y14.5-2009 Para. 4.20 "To invoke a restrained condition, a note is specified or referenced on the drawing defining the specific requirements"
Accompanying Fig 4-42 shows note referencing Work Instruction. So,... yes.

 

[pmarc]

CH's suggestion is good idea.

However I have some questions related to the concept of restraining of this particular part. Here are just 3 of them:
1. Will it really be a solid restraint if B is referenced at MMB (in position and profile callouts)?
2. What is MMB size for B referenced in profile FCF? In that callout B is referenced as secondary datum feature, but a geometric relationship between feature B and datum A is missing.
3. Why B is referenced RMB in perpendicularity callout for datum feature C?

 

[KENAT]

CheckerHater, my point was that the OP needs to have the Restrained Condition defined on their drawing.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[CheckerHater]

So was mine.
Sorry if it wasn't clear.
The book says that you may reference external document as work instruction, explaining in detail how exactly to hold the part down.
Also, on the drawing you provide as many datum targets as you want to make it happen.
I guess that counts as "defined on the drawing".
OP's drawing has a note, and some sort of WI right on it but lacking some detail about how DOFs are to be constrained like pmarc noticed; so some work should be done in that direction.
So, yes, it should be defined on the drawing as the standard suggests.

 

[ModulusCT]

Thanks for the ideas... Basically, from what I understand, the whole part is restrained on some kind of mandril or fixture that sits between the datum feature B (probably just clamped on).

pmarc, hello, thanks for the questions... I'm not quite sure how to answer those questions just yet, but if you've got any ideas I'd be happy to help. I'm studying and learning myself, and probably will know more about all of this than the product engineer when all is said and done. However, it's my guess that he's going to tell me that this part is already done like this in-house and, in typical fashion, the drawing is simply trying to catch up with the process already in place.

What I know for certain is this:

1) Datum feature B is to be validated in the free state to the tolerances specified (+.030/-.010)
2) Part is to be restrained around / thru or with datum feature B (how is not something I know at the moment)
3) All other requirements should be validated after the part is slipped over the roughly rectangular bar and clamped.

I'm going to work on this and get back to you guys... Thanks very much for the assistance.

I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE plants!!