Influence of veneer densification on the shear strength and temperature behavior inside the plywood during hot press

In this study the effect of veneer densification on the temperature change inside the plywood during the hot pressing step was analyzed. In addition, the shear strength of the plywood was determined. Rotary-cut birch veneer and phenol-formaldehyde resin were used to make the plywood samples. The multi-layers plywood structures made of densified and non-densified veneers with and without adhesive were investigated. Plywood products of 3, 5, 7, 9 and 11-layers were manufactured under laboratory conditions. It was found that the multi-layers plywood made of densified veneers was heated faster when compared to the plywood made of non-densified veneers. This will reduce the pressing time of plywood made of densified veneer by 2-29% depending on the number of veneer layers. The shear strength values of the plywood made of densified veneers were found two times higher than the normalized value of 1.0 MPa, meeting the EN 314-1 standard requirements. Findings of this work are useful for industrial applications to optimize the plywood production.