Plywood is a three-layer or multi-layer plate-like material, which is made by cutting wood segments into veneers or by square planing and then glued with adhesives. It is usually made of odd number of veneers and the fiber direction of adjacent veneers is perpendicular to each other.
Plywood is one of the commonly used materials for furniture. It is one of the three wood-based panels. It can also be used for aircraft, ships, trains, automobiles, buildings and packing boxes. A group of veneers is usually glued together perpendicular to each other in the direction of wood grain of adjacent layers. Usually, the surface plate and inner layer plate are symmetrically arranged on both sides of the central layer or core. It is made by pressing the glued veneers crisscross in the direction of wood grain and pressed with or without heating. The number of layers is usually odd, and even in a few cases. The difference of physical and mechanical properties between vertical and horizontal directions is small. The common types of plywood are plywood, plywood and so on. Plywood can improve the utilization rate of wood, which is a main way to save wood.
The usual length and width is 1220 ¡Á The thickness specifications are generally 3, 5, 9, 12, 15 and 18 mm. The main tree species are: Cinnamomum camphora, Salix, poplar, eucalyptus, etc.
Basic parameters of plate
Chinese Name: Plywood
Foreign name: Plywood
Essence: plate material
Also known as multilayer board; Laminate
Features: small deformation; The shrinkage rate is small; Smooth surface
According to the use: ordinary plywood; Veneer plywood
According to logs: hardwood plywood; Softwood plywood
Grade: superior product; First class products; Qualified products
Application: partition wall; Ceiling; Wainscot; Facade
In order to improve the anisotropic properties of natural wood as much as possible, and make the plywood uniform and stable in shape, two basic principles should be observed in the structure of plywood: one is symmetry; the other is symmetry; The other is that the fibers of adjacent layers are perpendicular to each other. The principle of symmetry requires that veneers on both sides of the symmetrical central plane of plywood should be symmetrical to each other regardless of wood properties, veneer thickness, layers, fiber direction, moisture content, etc. In the same plywood, veneers of single tree species and thickness can be used, and veneers of different tree species and thicknesses can also be used; However, the species and thickness of any two symmetrical veneers on both sides of the symmetrical central plane should be the same. The face and back plate are allowed to be different from the same tree species.
In order to make the structure of plywood conform to the above two basic principles, the number of layers should be odd. So plywood is usually made into three layers, five layers, seven layers and other odd layers. The name of each layer of plywood is: the surface veneer is called the surface panel, and the inner veneer is called the core board; The front panel is called the panel, and the back panel is called the back panel; In the core board, the fiber direction parallel to the surface plate is called long core plate or medium plate. When forming the cavity slab, the face plate and back plate must face outward.