How much is it per square metre to be decorated with plywood?
The principle of symmetry principle: single center plane plate on both sides of the water, both species veneer thickness, layer, manufacturing method, fiber direction and single board rate should correspond with each other, which is symmetrical on both sides of the center plane of each layer corresponding to the principle of plywood in different direction stress phase etc.. Therefore, when the change of veneer moisture content, its stable structure, no deformation, cracking and other defects; on the contrary, if the symmetry center plane of corresponding layer there are some differences, will make the center plane on both sides of single board stress is not equal, the deformation and cracking of plywood. Principle of odd number layer: because the structure of plywood is adjacent layer, the fiber direction of single board is perpendicular to each other, and must accord with symmetry principle, so its total number of layers must be odd number. Such as: three laminates, five laminates, seven laminates and so on. When the odd ply plywood is bent, the maximum horizontal shear stress acts on the central veneer to make it have greater strength. Even when the plywood is bent, the maximum horizontal shear stress acts on the adhesive layer, not on the veneer. It can destroy the adhesive layer and reduce the strength of plywood.
Classification of a class of plywood for weather resistance, water resistance, durability of plywood, from here have advantages of high temperature resistance, steam treatment; two types of plywood for waterproof plywood, can be immersed in cold water and hot water immersion in short time; three types of plywood for moisture resistant plywood, a short time can dip in cold water, suitable for indoor use at room temperature. For furniture and general construction purposes; four kinds of plywood is not waterproof plywood, used in indoor normal, general use plywood beech, basswood, ash, birch, elm, poplar etc..
A plywood is defined as a sheet of wood which is cut into a large single plate in the direction of the rings. The plates are glued and glued to each other in a direction perpendicular to the direction of the adjacent veneer. Single plate number is odd, generally three to thirteen layers, there are three common plywood, plywood, plywood, plywood (nine and thirteen on the market known as the three board, five board, nine board, thirteen board). The outermost single panel is called the panel, the reverse is called the back plate and the inner plate is called the core plate.
