Plywood veneer moisture content can be very high
if the wood is cut from a tree’s outer sapwood layer instead of its
inner heartwood core. To maintain a good glue bond between plywood
veneers and maximize veneer strength, plant operators must dry each
sheet within a tightly controlled moisture range. A wet section of
veneer in an otherwise dry heartwood sheet can make the sheet blow out
inside the steam press, causing delamination of the plywood and
resulting in lost production and increased costs.

Overdrying
the veneer can make it brittle and cause it to lose its strength
properties. Depending on the moisture profile, plant operators may
either place wet veneers in ambient air to equilibrate or send them
through a series of kilns at precisely controlled temperatures. The
moisture sort system also uses feedback from the kilns to optimize the
sort process, making it a key component in a plywood mill’s ability to
maximize productivity and quality.

Read the full case study