In a message dated 03/08/2000 10:34:21 AM Central Standard Time,
[log in to unmask] writes:

<< Dear Technetts,
 I have one custom design three leg SMT component. Two side leads (which are
 pretty massive and one middle center post). These leads are designed to
 create butt joints.
 Drawing specifies 0.004" coplanarity for all three leads. We are using
 0.007" stencil.
 Now $1,000 question. I am using my life line and asking audience to help me.
 It seems, that center post doesn't create good solder joint. There are
 cases, when it seats only 0.001" deep in the solder and may break easily.
 I cannot use more than 0.007" stencil due to other component packages.  I
 don't want to touch up each solder joint after reflow.
 What would you recommend? Please advise.
 Sincerely,
 Stella >>

Hi Stella!

If you can't increase stencil thickness, you might want to have the aperture
for the one pad that's giving you problems enlarged a bit (maybe 1-to-1, or
even a little bit larger) to give you additional solder volume.

I do that when I've got a 15-mil pitch part or micro-BGA on a board with
other 50-mil stuff. Even if you over-print the pad a little bit, it should
all wick together and coalesce into one fillet during reflow...

-Steve Gregory-

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