Grain Angle through Flake Thickness:Effect on Properties of a Structural Flakeboard.

摘要

The strength and stiffness of solid wood is affected greatly by the slope of grain through the specimen. This raises the question of whether the strength of a flake-type structural particleboard is affected in a similar manner with similar slopes of grain through the flake thickness. To explore this relationship, 0.020- by 1/2- by 2-inch-long Douglas-fir flakes were made at various carefully controlled grain angles through the thickness. Tests on 1/2-inch-thick flakeboards made with 5% phenolic resin showed that the reduction in strength as related to slope in grain was almost identical to that in solid wood. With a slope in grain of 1:5, the tensile strength parallel to the face was slightly less than 40% of that in test specimens having parallel grain. The linear movement of the flakeboards was also appreciably affected by slope in grain, being about five times as much with a slope of 1:5 as it was with parallel grain.