ROUNDING OR NOT, DIMENSION, TOLERANCE
ROUNDING OR NOT, DIMENSION, TOLERANCE
(OP)
Lest say a dimension, .040+/-.001. The part is .0411. Good or Bad ?
Please enter your VOTE.
We have a big fight here !!!
Please enter your VOTE.
We have a big fight here !!!





RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
At least if ASME Y14.5M-1994 [section 2.4] (and as far as I know other versions of that std) all limits are absolute. "Dimensional limits, regardless of the number of decimal places, are used as if they were continued with zeros."
So .040+-.001 means the upper limit would be .0410000000000000000000000000000000000000000000000...0 and there is no need for any voting.
Of course, I suppose potentially someone could argue your measurement error could come into play but generally that is taken to reduce the available tolerance not increase it.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
Frank
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
now i have something to go back to argue with our QA manager who told me that he have 40 yrs experience.
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
It's exactly the same, ASME or ISO. Infinite number of zeros follows.
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
If it is measurement error, should it not be remeasured and the correct data entered it its place?
Frank
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
Petrotrim Services
www.petrotrim.com
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
The part still being useable depends on the function in the assembly.
The QA manager's 40 years experience and $4.50 will get him a Starbuck's, but won't make a bad part good.
"Wildfires are dangerous, hard to control, and economically catastrophic."
Ben Loosli
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
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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: ROUNDING OR NOT, DIMENSION, TOLERANCE
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
So it is perfectly possible to design a part wrong, manufacture it incorrectly and inspect it incorrectly but have no negative downside over a 40 year period, all of which goes to prove it is better to be lucky than good.
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
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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: ROUNDING OR NOT, DIMENSION, TOLERANCE
A part can't be made perfect, and a measurement is never perfect - certain amount of measurement uncertainty will be always coming into play. And this uncertainty may make a huge difference, especially in cases like this one.
So from purely theoretical point of view ".0411" means the feature/part does not meet drawing specification. However, if the measurement uncertainty has been considered, the verdict may not be that obvious.
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
The case on hands is what ISO calls Correlation Ambiguity, meaning, in plain words, that part specification does not represent functional requirements properly.
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
our QA man was wrong on this. he was saying we could accept up to .04149999....9.
everyone in my eng dept do not agree. but can not remember where the PRINT is.
now, we have ANSI Y14.5 section 2.4.
we understand the accuracy requirements for the measuring instruments and the whatever the uncertainty of it.
thanks again.
RE: ROUNDING OR NOT, DIMENSION, TOLERANCE
Good to whoever doesn't care, or know what it means.
Chris
SolidWorks 13
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