Subject: | |
From: | simon.ipc.org!pbni.attmail.com!PBN!PBN1!JMcGee (John McGee) |
Date: | Wed, 14 Aug 1996 17:27:00 +0000 |
Content-Type: | Text/Plain |
Parts/Attachments: |
|
|
And now for something decidedly low-tech...
I'm pursuing the (painful) process of updating an older set of assembly
workmanship standards, as an internal inspection aid.
Per our specs, solder is not permitted to wick into the lead bend area,
for axial leaded components, mounted parallel to the board surface.
This stance agrees with IPC-SM-780 (section 8.4.3.). It does not, however,
agree with A-610 (4.2.C). Further, in J-STD-001, Table 11-1, item 17, it
does
not state that solder in the stress relief bend is acceptable, but rather
that
it "does not constitute elimination of stress relief".
I'm being asked to explain the reasoning behind my proposed change
(allowing solder) and our older spec (not allowing solder), before it will
be
accepted. This is, in essence, asking me to explain the seeming
contradiction
outlined above.
I'm at a loss on this one. Hope someone can help.
Is this one of those conditions that cannot be traced to actual failures in
the field
(and is, therefore, no longer considered a reliability risk) or is there
other
reasoning and/or testing which can be cited to illustrate that we were over-
cautious in the past? I'm guessing the latter - how else can it be claimed
that
filling the bend does not eliminate the relief created by the bend?
Any help will be appreciated.
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
|
|
|