An improved hot gas pressing system for use in manufacturing wood-based
composite panels reduces in-press time substantially while reducing
blistering, pitting, and warping in the final panel. Condensable steam as
the preferred gas is injected into both faces of the mat after the press
closes to an intermediate position compressing the mat to an intermediate
density. After the steam is applied for a predetermined time period at the
intermediate density quickly raising the mat temperature, a steam through
step is applied after which the press is closed to its final position.
Steam is reapplied to both surfaces of the densified mat to maintain
temperature further reducing cure time of the adhesive after which venting
and vacuum steps are applied to both surfaces of the mat to reduce
internal pressure and remove moisture from the mat prior to opening of the
press.