Hi Dick - sometimes tin/lead solder surfaces get "texture" due to the
solidification behavior of the solder joints. Years ago "grainy" solder was
"bad" because the specifications required "bright and shiny" solder joints.
Industry data has shown that solder joint appearance is not the best
assessment of solder joint quality. There are many situations solder joints
having "texture" is not an issue. For example, if you have a hot reflow
profile which allows the solder joint microstructure to form large lead
(Pb) dendrites then the solder joint surface can look rough as the
dendrites cause topography differences. Once Steve posts the picture,
TechNet should be able to provide a more detailed assessment.

Dave Hillman
Rockwell Collins
[log in to unmask]

On Mon, Aug 31, 2015 at 11:14 AM, Richard Krug <[log in to unmask]> wrote:

> I've got something I haven't seen before.  We wave soldered boards with
> Sn63Pb37 and found a "textured" surface after soldering.
> We seem to have good wetting, but it looks like we have "lumps"  under the
> solder surface.  The lumps are most visible where the solder is thin, but
> can also be found on thicker solder joints as well.
> The application is class 3.  We do monthly solder analysis on the pot so I
> don't think it is contamination in the solder.
> Any insights would be appreciated
>
> I know the picture will be stripped out of the message, but I'm copying
> Steve Gregory directly in hopes he can post the picture.
>
> Steve - Please post this picture to go with my question for the TechNet
> forum.  Thanks in advance.
>
> Dick Krug, CSSBB, CSMTPE
> Lead Process Engineer
> Sparton Brooksville, LLC
> 30167 Power Line Road
> Brooksville, FL  34602-8299
> (352) 540-4012
> [log in to unmask]
>
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