Hi Dick - based on your information and the picture, I think what you are
seeing is typical solder microstructure "texture". A cross section would be
definitive if you needed that level of confidence.
Dave
On Mon, Aug 31, 2015 at 1:28 PM, Richard Krug <[log in to unmask]> wrote:
> First, thanks for posting picture Steve.
>
> I'll try to answer all questions received thus far.
> Solder is Sn63Pb37
> Board is wave soldered.
> Topside board temp before the wave ~115C
> Leads of this component are solder dipped, alloy not specified,
> but SnPb. Similar appearance on virtually all solder joints on the board.
> This result was found on all boards of this work order, but not on
> other assemblies soldered on the same wave.
> Flux coverage could be a cause, but dross is unlikely since not on
> other assemblies.
> Flux is ORH. Boards have been washed with saponified water.
>
> Thanks for the questions.
>
> 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]
>
>
> -----Original Message-----
> From: Guy Ramsey [mailto:[log in to unmask]]
> Sent: Monday, August 31, 2015 1:43 PM
> To: 'TechNet E-Mail Forum'; Richard Krug
> Subject: RE: [TN] Textured Solder?
>
> Might be past time to clean the wave guide. I have seen something like
> that when dross breaks off the inside of the guide and gets mixed in with
> the wave.
> I notice that three of the leads don't look like they wetted very well.
> Are you sure you have good flux coverage?
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Krug
> Sent: Monday, August 31, 2015 12:15 PM
> To: [log in to unmask]
> Subject: [TN] Textured Solder?
>
> 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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