>>>
[log in to unmask] 05/13/02 07:32AM >>>
Jim, Guy,
Nancy and others,
I respectfully submit the following:
If the intent for
the 50% hole fill allowance (in regard to PTHs with
thermal or conductor
planes) is to be limited to class 2 then the exception
should be listed
directly under "Acceptable - Class 2" not under "Defect -
Class 3" on page
6-7 and table 6-2 should have a note that flags this
allowance for Class
2.
As we all know, it is impossible to clearly and concisely write with
the
English language in such a manner that all readers will properly
understand
the meaning or intent of the words that is or are being
conveyed.
Having not participated in the IPC-A-610 meetings (as Guy
referred to), I
and others do not have the luxury of understand the intent of
certain
requirements -- all that is affored to us is the written words.
In
this case, the intent may have been to limit the 50% hole fill
requirement to
class 2 but the printed words do not support this beyond the
shadow of a
doubt.
I will prepare a Standard Improvement Form for IPC-A-610C and forward
to IPC
so the committee can fill more hours with antiquated prose about
this
subject.
I on the other hand still believe that 50% hole fill on most
class 3
products will not cause a problem in terms of long term reliability
even
under extreme conditions as apposed to reworking the solder
connection.
This statement is made under the premise that a well defined,
developed and
controlled process is utilized.
If there is any objective
evidence that 50% hole fill is a problem, I along
with Sir Werner would like
to review the data, hardware, photomicrographs,
cross-sections,
etc.
Steve
Sauer
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