huangyhg

mmc for radius
hi,
this may be a very weird question.
can we give mmc to a radius dimension?
i looked in to few gd&t books, but it does not mention about the radius. on radius only "controlled radius" is mentioned
if yes, please help me. i have attached pdf of my product. when the diameter with datum "a" is at maximum material condition the radius should be 8.5mm.
as dia "a" reduces the radius should also reduce.
please help me.
thanks,

no you can't. mmc can only be applied to a feature of size and a radius is not a feature of size.
powerhound, gdtp t-0419
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paramathma,
if you want to define an mmc state, you should apply a profile tolerance to the radius. you could apply a profile boundary (see figure 6-16) inside the radius so that your drawing explicitly shows the mmc state.
jhg
bingo to drawoh!
matt lorono
cad engineer/ecn analyst
silicon valley, ca
i looked for fig. 6-16 in both the asme y14.5-94 and also 2009.
in the 94 edition on page 168, we have a profile and parallelism example - no mmc. in the 2009 edition, we have a perpendicular example for fig. 6-16- no mmc so i just don't know where this information is coming from.
i do know that in the 2009 standard, we can have a datum surface of a radius shown with a a profile at mmc but is this drawing to that standard?
as powerhound stated, we cannot have a mmc on a radius but only on features of size.
dave d.
dingy2,
i did not say is was mmc. i said that it was in an mmc state. i read powerhound's message.
a profile tolerance locates the feature to the datums, and controls the size and shape. you can use it to define a maximum possible or allowable shape. you may not be allowed to call it mmc, but it is effectively mmc.
jhg
thank you very much
could you please provide me with an example.
thanks
paramathma,
see asme y14.5m-1994 figure 6-16.
as noted above, there is no mmc symbol, and the terminology is not valid, however, the curved part of the geometry, as drawn, is the maximum sized allowable state of the material.
jhg
figure 6-16 does reflect a unilateral tolerance from it mmc size but the original question was "can we give mmc to a radius dimension?" the answer to that is - no.
dave d.
thanks all

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