Interesting question.  I know that we and our military customers typically
would reject a microsection showing .0018 annular ring.   However, after
reviewing IPC-6011 para 1.3.1, "Acceptability when limiting values are
specified" says, "an observed value shall be rounded of to the nearest [0.1
inch, 0.01 inch or 0.001 inch] and compared to the limiting value.

If the specification calls out .002 mil annular ring, and a microsection
reads .0018, it would be rounded to .002 and it appears that it would be
acceptable and specification compliant.

If the specification called out  .0020 minimum annular ring,(it dosn't) then
a reading of .0018 would be rejectable based upon the four decimal places in
the callout.

It depends upon the number of decimal places in the specification callout.

IPC-RB-276 also clarified this point in para 1.4.2.   It is basically the
same verbage aws IPC-6011

So, my take is that by the specs, .0018 would be acceptable.  However, I
think I would still have a battle with several customer on this issue.

Adios'
Jim


At 01:42 PM 9/30/97 -0600, you wrote:
>I have an ongoing arguement with someone.  If there is .0018" of annular
>ring, are you allowed to "round-up" to .002"?  This is based on the fact
>that the measuring device resolves to four decimal places but the spec. only
>gives three.
>
>I think a minimum is just that, nothing below is acceptable.  Your
>thoughts..........
>
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=====================================================

Jim McNeal  Q.A.and Eng. Mgr.
Electro Plate Circuitry, Inc.
Carrollton, Tx
Ph. 214-466-0818
EMAIL  [log in to unmask]

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