Hi Lou, Steve
I agree with Steve - if it makes sense $$$ or schedule / parts availability - salvage it. If it's a cheapo then the decision is obvious.
My "best" submarine experience: first month on the new job. Been in tweaking the wave machine all morning, and the boss wanders in looking for me. While chatting he watches a board going over the wave... SWOOSH.
Actually - if I'd been thinking fast I would have parlayed that into retrofitting the chain with L fingers (it's got V on it). I suspect I had not quite fitted the board into the V... but as Steve says - the shock and horror...
regards
Graham Collins
Process Engineer,
Northrop Grumman
Atlantic Facility of Litton Systems Canada
(902) 873-2000 ext 6215
>>> [log in to unmask] 11/29/01 08:41PM >>>
Hi Lou!
I think that this is the one event when it happens, eclipses any other event
in printed circuit assembly manufacturing, that brings forth a flood (no pun
intended) of intense emotions from the observer...shock, horror, terror,
regret, desperation, depression (it's not for the faint hearted). Those
emotions multiply exponentially depending on the assemblies complexity and
value. It does happen though...I think some of my gray hair has come from a
few of those over the years.
But in those times when it came down to having to salvage the mess, I would
say there were no problems. The decision would always be made based on
dollars. Did it make more economic sense to put the extensive labor needed to
clean-up everything, or just start from scratch again...
One thing to do if you're quick enough when it happens, is to try and grab
the board as it comes off the conveyer and "pour" the solder off as quickly
as you can, and in such a way to involve the least number of components, or
the obviously complex ones, PGA's, BGA's, etc...takes for some quick thinking
when you're staring in horror as the event unfolds!
Molten solder on top of the board hasn't ruined the PCB in my experience,
it's just a matter of cleaning-up all the shorts that happen...again, it's a
economics thing. If you want/need to salvage a board that's "sub'ed", I don't
think quality is that much of a concern if it's done by someone who can
handle something like this.
It's happened a time or two with me, and I've bought more than a few lunches
for a few ladies that were magicians with soldering irons and solder
extractors...they are worth their weight in gold.
-Steve Gregory-
> TechNetters, I know there was discussion of this before, many months ago,
> but I can't track down the postings in the archives. Please comment.
>
> We have with solder on some of the top side, surrounding some components
> (ICs and passives). It was dunked in wave solder. Are boards that have
> "submarined" (I think someone used this term in the earlier discussion)
> useable if excess solder is removed? Never useable? Sometimes?
>
> I could say it's OK, since submarining shouldn't be as bad as HASL, but
> would like some expert comments.
>
> Lou Hart
> Compunetix Quality Assurance
>
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