Main loss in the production process of high humidity-resistant exterior plywood

In the whole production process of high humidity-resistant exterior plywood, core drying, blanking, hot pressing, trimming and sanding have an impact on wood loss. It is divided into tangible loss and intangible loss. Wood loss is related to factors such as the original wood species, log specifications, equipment status, process technology, and finished board specifications.

High-humidity outdoor plywood has a high moisture content after core-cutting, and the core plate must be dried to meet the requirements of the gluing process. After drying, the wood becomes smaller in size and is called dry shrinkage. As the moisture content decreases, the length, width and thickness of the core sheet shrink. The shrinkage loss is related to the tree species of the core board, the moisture content of the core board, and the thickness of the core board. The shrinkage loss rate is generally 4% to 10%.

High-humidity outdoor plywood assembly finishing includes shearing, paneling and repairing. The dried strip core plate and the zero core plate are cut into a standard core plate and a splicable core plate, and the narrow core plate is spliced into a whole core plate, and the defective whole core plate can be repaired to achieve the process. Quality requirements. The amount of waste core board produced by this process is mainly related to the operator's familiarity with the core board standard and the quality of the core board. The loss rate is generally 2% to 4%.

The hot pressing of the high-humidity outdoor plywood is to firmly glue the slabs of the glued assembly to a certain temperature and a certain pressure. As the slab temperature and moisture content change during hot pressing, the wood is gradually compressed and the slab thickness is gradually reduced. The loss is compression loss, which is related to the hot pressing temperature, unit pressure, hot pressing time, tree species and water content of the plywood. The loss rate is generally 3% to 8%.