Mime-Version: |
1.0 |
Sender: |
|
Subject: |
|
From: |
|
Date: |
Wed, 25 Aug 1999 11:04:36 -0400 |
Content-type: |
text/plain; charset=us-ascii |
Reply-To: |
|
Parts/Attachments: |
|
|
Phil mentioned:
>i really doubt that your customer would accept your nitric acid, acetic
acid
>cleaning process without data to backup your capability to clean up the
>cleaner. i mean this stuff will eat up copper. nothing like flying
around
>in an aircraft while residues are eating away at your electronics.
Ouch! Yes, I'd recommend against this too. In a previous life, dipping a
PDP11 module (ok, so it was an OLD previous life!!) into a weak acid
solution
to clean off some organic flux residue resulted in electro-plating shorts
between
the leads of cerdip parts. The boards had come right off test, and likely
had
charge still in various caps, etc... I delidded the parts, sheared the bond
wires
and low resistance shorts still existed between pins.
A 5% visual reject rate became a 80% functional failure rate, and we ended
up scrapping the entire run. (the manufacturing engineer who had come up
with this idea was VERY popular for a couple weeks!!")
The moral of the story was "beware of getting any acid solutions anywhere
near a populated PWB"...
John
John Brewer
Component Engineering Supervisor
Square D Company
[log in to unmask]
##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe: SUBSCRIBE TECHNET <your full name>
To unsubscribe: SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################
|
|
|