Steve
We regularly do this operation on boards coated with Electrolube HPA
(high performance acrylic)(mods, repairs..general screw ups :-))
Depending on the operation we either burn through or remove locally,
remove the part, prepare for re-solder, attach new part, clean locally,
re-conformal coat using brush, low level bake for a few hours.
Its not a nice job, and certainly one we refrain from doing in
public...but it works.
Ian Squires
Production Engineering Manager
Redifon MEL, Crawley, UK
Tel: 44 (0) 1293 466300 xT 2425
----------
From: [log in to unmask]
Sent: 17 May 1999 23:54
To: [log in to unmask]
Subject: [TN] Rework of Acrylic Conformal Coated
--------------------------------------------------------------------------
--
Hi ya'll!
We just got a rework job in from a customer where we're gonna change a
PLCC28
out for them, remove it and replace it with another. The board has been
conformal coated with an Acrylic conformal coating (Humiseal type 1B73 I
believe...).
I know reworking can be done just by burning through the coating, and
then
cleaning up the pads real good before putting the new part back down.
We're
water soluble, so we're gonna have to run the boards through the cleaner
to
clean the flux residues...and I know that we'll damage the coating when
putting it through the cleaner. On the boards that I've looked at, the
coating has been compromised anyway on spots here and there just from the
handling...acrylic is not too tough.
I told our customer that the coating was gonna be pretty raggy looking
when
he got the boards back from us, and we're not in the conformal coating
business. But what's bothering me, is that I think they've got some spray
cans and they're gonna try and touch-up things themselves...against my
strong
recommendations. I think the boards should be stripped of the coating
that's
on there now, baked, and then re-coated.
But like I said, we're not in the conformal coating business, and I've
not
worked much with the stuff anyway. I'm just thinking logically about
it...am
I sweating things too much?
Thanks!
-Steve Gregory-
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--
Ian Squires [log in to unmask]
http://www.rmel.com Tel: +44 (0)1293 446300
This email and the sender's address are confidential
and may also be privileged. If you are not the
intended recipient, please notify us immediately.
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