As fabricators, we have had it drilled into us that "flat solder is best"
for assembly. We have never received a return from any customer for "thin
solder", but I can't say the opposite is true. My process engineers desire
to alter our hot air solder leveling parameters to eliminate any future
chances of returns for thick solder. Our SPC data suggests that lowering the
peak solder thicknesses results in exceptionally thin solder (IMO) on
certain pad geometries. My question:

How thin is too thin? As assemblers, when (at what thickness or process
conditions) would you return boards to the fabricator?


[log in to unmask] (Glynn Shaw)