Hi Inge,
Large fillets have always been a problem source.
Besides causing the obvious tombstoning problem, they put those components
into vise-like jaws and crack them. CCs are the only issue I am aware of that
Class 3 product is consistently less reliable than Class 2 product because of
the offset limitation.
I have been pushing for a long time for soldering pads no wider than half the
component width, and the elimination ar at least almost elimination of
fillets on CCs and RCs.
You may want to take a look at my columns in GSMT&P magazine, see Engelmaier,
W., “Achieving Solder Joint Reliability in a Lead-Free World, Part 1,”
Global SMT & Packaging, Vol. 7, No. 6, June 2007, pp. 40-42
and
Engelmaier, W., “Lead-Free (LF) Wave-Soldering: Can (Should) It Be Eliminated,
” Global SMT & Packaging, Vol. 5, No. 9, October 2005, pp. 46-50.
Skoal [with today's meaning, not of those blood0thirsty Vikings]
Werner
**************
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