Steve -

What you describe sounds a whole lot like a condition I've called "drainage".
I would best describe it as a situation where the combination of preheat and
solder pot heat are just right to lower the viscosity of your solder enough
that trailing downforce from the wave can strip it out of the barrels, in
addition to removing the excess.

I assume you've done all the standard stuff, such as comparing a current MOLE
profile to the original, checking the solder pool length on the specimen, etc.
 One other possibility is that you have some sensors in the preheat or
solderpot that are aging and drifting from their original points.

Try a couple of panels at a slightly higher conveyor speed to see if this
improves the situation.  If so, then a little minor profile tweaking may solve
the whole problem.

Good luck - Kelly

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################