Good afternoon Rob,
2 quick things come to mind:
 1. With components already mounted on the bottom side of the board,
tooling nests (fixtures, board locks, etc.,) will be required for each
board type to provide support during solder paste printing.  This may add
additional cost in either tooling or setup/changeover.
 2. Check with your adhesive mfr., to determine compatibility and bond
strength after additional thermal exposure.  The one side effect would be
that the bond (between pcb and component) may weaken and the components
will fall off during subsequent assembly and wave soldering.  The mfr may
suggest another formulation that could satisfy your new requirements.

Personally, I would not change the current process flow to eliminate a
board flip.  The change seems to add additional cost/labor and
uncertainty versus the board flip.

Steve Sauer

 -----Original Message-----
We are in the process of determining the most efficient way to run our
smt
process.  Right now we only have a half line and are looking at adding
the
back half of the line.  Our current process takes us through reflow
first,
flip the product, then move the product to the beginning of the line and
then run the bottom side (curing).  If we use this current process with
the
second half of the line, we will need to flip the product over before it
reaches the hand insertion line.  Our thoughts are can we run bottom
(curing) first, flip the product, and then run top side (reflow)?  This
will require us to only flip the product once.  Are there any issues with
running curing first and then running reflow?  After the glue is cured,
it
will be passing through the oven during reflow at a higher temperature
than
the curing temperature.  Will the reflow temperature have any effect on
the
glue?

Rob Williams

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