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
>
> ##############################################################
> 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
> ##############################################################
##############################################################
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
##############################################################
##############################################################
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
##############################################################
|
