ISO Flatness per Unit area?
ISO Flatness per Unit area?
(OP)
Please ref to Sec A-A, Flatness|0.2/50
Is it a flatness per unit area callout? flatness is allowed to apply on a unit basis in ASME Y14.5, how about ISO?
Is 50 an area of 50 X 50 square or Ø50 circle?
Thanks for all of your comments
SeasonLee
Is it a flatness per unit area callout? flatness is allowed to apply on a unit basis in ASME Y14.5, how about ISO?
Is 50 an area of 50 X 50 square or Ø50 circle?
Thanks for all of your comments
SeasonLee





RE: ISO Flatness per Unit area?
In my opinion this is not clear. My best guess would be that instead of controlling flatness of the surface for whole height of the part (reference dimension 222.41) someone wants to refine the area to height=50 and because the surface does not have fixed dimension in orthogonal direction there is lack of second value clearly defining per unit area in flatness FCF.
RE: ISO Flatness per Unit area?
There is 2012 version out there, but I didn’t have a chance to see it.
Didn’t make it any more clear, did I?
RE: ISO Flatness per Unit area?
I guess we do not want to start the discussion about extension of principles again, do we, CH?
RE: ISO Flatness per Unit area?
RE: ISO Flatness per Unit area?
SeasonLee
RE: ISO Flatness per Unit area?
Having said that, my copy of ISO 1101-1983 shows an example of parallelism per unit length. It says that the value applies to all lines of the restricted length in any position and any direction. I would think the same should apply to flatness since is is quite similar to parallelism without a datum reference. This does match the OP's symbol.
So I think it means 0.2 mm of flatness in any 50 mm length in any position and direction on the indicated surface.
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RE: ISO Flatness per Unit area?
Joe
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RE: ISO Flatness per Unit area?
I can't find out what you mentioned on ISO 1101-2004,would you mind to post a snapshot. BTW,there is always a datum reference on parallelism.
SeasonLee
RE: ISO Flatness per Unit area?
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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.
RE: ISO Flatness per Unit area?
SeasonLee
RE: ISO Flatness per Unit area?
SeasonLee
RE: ISO Flatness per Unit area?
http://www.eng-tips.com/viewthread.cfm?qid=327653