Servus Graham, very glad to hear you (seem flat out lately) .
Funny you mention weather (the classic Imperial conversation);
just stumbled from Resmed's annual party in Olympic Aquatic Center
('instant dismissal for anybody "accidentally" dropping into pool' ;
whispered the HR director [a gentle soul]into my still sober[initially]ear)
;
and we chatted up this global warming phenomenon :
It may be true poor Fiji 's sinking ; but here in Sydney it's "evening out"
that is winters are milder ; summers cooler (hits only 30'C's, not 40's);
boring paradise for likes me ,
(driving to inland desert for few days over break, this allup greenery is
too much lately)
Back to the subject, this is a pretty good bone (your reply);
so I hope you won't get upset if I throw it back to the wolf pack (Jason
especially);
as i feel correctly corrected .
(while acknowledging you as one of the true gentlemen of the net ,
even savages like me do have a sense of fair play).
Au(ch); yo' right, a lot of folks ain't that hot on it,
but as over decades everybody hired me as the "switch man" ,
in oak wafers, fingers, pads, boards, etc.;
i got stuck with this Midas syndrome in which i feel perhaps way too
comfortable .
Considering the ounce price and general populus trends ,
i doubt ever emerging from this limitation .
As far as OSP goes ; due to my love of solid versatile foundations (NiAu)and
duty of switching on boards (pads);
i gave it a shoot in initial substrate finish validations ;
than concluded i really did not want to go this far .
It certainly sounds OSP double reflow AND wave with wet results is as
challenging as wet top pads on gold ;
so my hat 's down (for G. Washington as well) to you .
Same to yo' (ALL) > "safe" break mate
(that Inge's pumpkin stuff i'd not sip alive without proper spectral
analysis; wild stuff, as the creator)
Here you go Jason, read below how it's done
pk
-----Original Message-----
From: Collins, Graham [mailto:[log in to unmask]]
Sent: Saturday, 18 December 1999 6:46
To: 'Paul Klasek'
Subject: RE: [TN] OSP and wave soldering
Paul
Season's greetings! How's the weather down there, I trust a bit warmer than
here.
I have to disagree with you somewhat. Built a couple of thousand beasties
with OSP. Double sided reflow, then partial wave (using a pan pallet) and a
weak no-clean (Multicore X-33-03K9). The boards were a memory board, so
chips on both sides, then we'd add a big PGA and the connector, wave solder
those and out the door. OK, we tested them, but that doesn't interest me.
Anyway, it went OK so long as we ran them through the wave solder machine
within a day of the first reflow cycle. Obviously you can do this in a 3
shift operation, it would be a bit more problem in a 1 shift / day place.
First ones were built with Entek, but we switched to Entek plus to give us a
better process window - they claimed you could go 3 days in build. We stuck
with 1 day, Entek plus didn't make much difference for us.
The other thing about the no-clean is that your design has to be reasonably
thermally balanced, and you have to watch the profile - but I'm sure you
know that. I'll admit it isn't as forgiving as NiAu but some don't like
that stuff.
Hey - have a good Christmas! Not too much pumpkin wine!
- Graham Collins
-----Original Message-----
From: Paul Klasek [mailto:[log in to unmask]]
Sent: Thursday, December 16, 1999 5:47 PM
To: [log in to unmask]
Subject: Re: [TN] OSP and wave soldering
Good point Gary, it's up-hill all the way.
Jason, i may be biased , but always got NiAu cheaper than HASL ,
OSP is NOT meant to be for multipass process .
Unless you engage inert techniques (paradox of cost of process versus cost
of board);
your chances are very much subzero .
To give you some ammunition to defend yourself in this design nonsense :
To order OSP for multipass with weak no clean to top it, is (now, how do i
put it politely ?).
Ignorant , suppose ;
you're in a position if gluing together broken glass hammer, makes no sense
whicheverway .
Not only that , despite the fact that normally mildly starved barrel fills
actually increase reliability,
being voids or underfill,
i would not be so hopeful in this case as i'd question the oxidized
adhesion,
that is a severe risk of running dry joints .
Sorry to be gloomy , don't envy you, won't even wish good luck, this is a
design crime .
Paul Klasek
ResMed
-----Original Message-----
From: Gary Camac [mailto:[log in to unmask]]
Sent: Friday, 17 December 1999 1:58
To: [log in to unmask]
Subject: Re: [TN] OSP and wave soldering
Jason,
Am I missing something? If you are fluxing with a water soluble, aren't you
violating
your customer's desire to use a no clean. I would assume that your customer
is
concerned about ionic residue since they a specing a no clean. I would be
more
concerned with the approach you are using than I would with just soldering
with the
water soluble. Wouldn't a full solder cycle be less likely to leave ionic
contaminates? I guess that is a question for a flux guru.
I have only played with OSPs only a little and I don't run nitrogen in any
soldering
operations. The first thing I didn't like about them was the poor spread of
the solder
on the first pass. I could put a spot of paste on a pad and it would not
wet much past
the area it was deposited at. I also thought the wetting angles, though
acceptable,
were greater than I am used to seeing.
I believe nitrogen is necessary in all soldering operations in order to be
successful
with an OSP. Anyone - please correct me if I am wrong here.
Jason Smith wrote:
> I am having problems with wave soldering OSP boards. After the boards
have seen
> a heat cycle (reflow), they are impossible to get hole fill on topside
without
> first cleaning the boards to remove either oxidation or hardened OSP. I
don't
> know which one I have because I haven't had them analyzed yet. The flux
used to
> wave solder the boards is a very weak customer dictated rosin no clean
flux.
> The OSP is Cu106A. I am not familiar with OSPs. They won't do HASL
either.
> Any insight? Suggestions? Assistance?
>
> As it stands now, the process is to flux with high solids water
soluble/heat to
> clean the board-->wash off flux-->immediately wave solder with rosin
containing
> no clean. This is not a production process........
>
> Jason Smith
> Process Materials Engineer
> Lexmark Electronics
>
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