Steam-assisted hot-pressing of construction plywood
1994
Jokerst, R.W. | Geimer, R.L.
This study was designed to determine if steam injection pressing used for fiberboard, particleboard, and flakeboard could be adapted to the pressing of plywood. Plywood panels were fabricated with and without adhesive and then pressed to determine the effects of steam injection time, steam injection pressure, and press pressure on heat transfer rate, moisture distribution, thickness loss, and adhesive-bond integrity. The time to reach 220 degrees F (104 degrees C) in the center glueline of five-ply, 0.5-inch- (12.7-mm-) thick Douglas-fir plywood was reduced 15 percent using certain combinations of steam injection pressing variables. Heat transfer rates increased with high steam pressures, lengthened steam times, and low panel pressures. However, the combination of variables that produce rapid heat transfer rates is also prone to induce excessive panel moisture with subsequent delamination.
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