Most of the drawings specify reflow. This one didn’t. We made a supplier
change and the new vendor followed the drawing. We think the old supplier
reflows them like all the others. We printed and reflowed. They looked
great. But, I can see they will oxidize quickly.

On Mon, Aug 5, 2019 at 9:10 AM David Hillman <[log in to unmask]>
wrote:

> 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
> [log in to unmask]
>
>
> 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?
>>
>