Dave,
I think you are thinking of popcorn, not PCB's... Peanut oil.... :-) :-) Isn't this a Friday question?
Scott Decker | Senior Engineer, PCB Design Services CID+ | Electronic Systems Center
COLLINS AEROSPACE
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
Sent: Monday, August 5, 2019 6:10 AM
To: [log in to unmask]
Subject: Re: [TN] [External] [TN] electroplated tin-lead
Hi Guy - well, we used to use electroplated SnPb as a standard printed circuit board finish for years until the modern immersion type finishes took over. However, we always reflowed/fused the electroplated SnPb finishes (typically in peanut oil) as a non-fused electroplated SnPb finish had poor solderability characteristics (i.e. oxidation). There is an "art"
to fusing an electrolplated SnPb surface finish uniformly. Perhaps what you are observing is a supplier difference is their fusing process.
Dave Hillman
Collins Aerospace
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On Fri, Aug 2, 2019 at 3:07 PM Guy Ramsey <[log in to unmask]> wrote:
> One of our customers specifies electroplated tin-lead reflowed as a
> surface finish.
> It yields relatively nice flat pads and a good solderable finish.
> One of the drawings did not specify "reflowed". Everything seemed fine.
> Then, we had to switch vendors.
> The new vendor asked about this odd request for surface finish.
> Electroplated Sn-Pb, not reflowed. But, they followed the drawing notes.
> Now, we have the boards in hand. They look bad. We are running a test
> print on the solder sample but I am dubious.
> Have any of you experience with electroplated Sn-Pb as a surface finish?
>
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