We are having difficulties soldering bare copper FPCs. The current process
requires prebaking the FPCs for an hour at 100 degC, prior to the SMT
assembly processes. This is intended to reduce the possibility of
delamination later in the process (at reflow). However, this is giving us
problems during reflow because the bare copper pads on the flex oxidize and
make it hard to solder. Can anybody suggest an alternative process to solve
this? Any help is greatly appreciated.

Luke B. Mendoza
Electronic Asemblies, Inc.
Manila, Philippines