Message
The
Print did not specify SMOBC. But it also didn't specify SOS (Soldermask over
solder) either! The implication is that the order of the notes IMPLIES that we
want soldermask after the solder coating process. Don't all
PCB vendors know that the solder under the soldermask will reflow,
wrinkle and damage the soldermask in assembly? If we have soldermask on a
thru hole technology board.... we are going to wave solder the board. Why
would a vendor interpret the drawing in such a way as to compromise the
performance of the board? I can't believe this is still happening in 2002.
I thought we learned our lesson back in 1980.....the first time I ever
saw anyone DO that...
Doesn't IPC have a spec that tells us not to do it that
way?
Bill
Brooks
Hi Bill!
Was that called out on the
fab drawing? I've ran across a few boards here that still call that out on the
drawing, and TRY and get that changed before the boards are fabbed...most of
the time I've been lucky, but there's been a few that slipped by me.
Bottomline, if it's called out on the drawing, you don't have much
recourse...
-Steve Gregory-
Anyone aware of a spec that sets the accept/reject criteria for
boards that
come in with solder UNDER the soldermask? Is this actually
done as a
legitimate practice? WHY would a vendor make the boards this
way? Shouldn't
we be making all boards to be SMOBC when there is a
soldermask?
Bill Brooks
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