Nowadays, plywood is a three-layer or multi-layer board-like material made by turning wood segments into veneers or cutting thin wood by square planing, and then glued together with adhesive. Generally, odd numbered veneers are used, and the fiber directions of adjacent veneers are glued together in a straight way.
In order to improve the anisotropy characteristics of natural wood as far as possible, so that the plywood characteristics uniform, stable shape, general plywood in the structure should follow a few principle points, one is symmetrical, two is adjacent layer veneer fiber mutually straight. Symmetry principle is for veneer, plywood center of symmetry plane two heads regardless of wood properties, veneer thickness and layers, the fiber direction, moisture content, etc., should be symmetrical, each with a piece of plywood, you can use a single tree species and the thickness of the veneer, also can use different tree species and the thickness of veneer, but no two layers of center of symmetry plane two symmetrical single tree species and thickness should be the same, each other back tolerance is not the same tree species.
Plywood manufacturers understand that plywood this sheet is more common in our lives to build decorative materials, but there are many products on the market, we want to use qualified products, also need to distinguish the quality of the product. In order to make the structure of plywood in accordance with the above two basic principles, plywood should have an odd number of layers, so plywood is generally made with an odd number of layers of three, five, and seven. The surface veneer is called the table board, the inner veneer is called the core board, the front of the table board is called the panel, the back of the table board is called the back board, in the core board, the fiber direction is parallel to the table board is called the long core board or the middle board, in the composition of cavity slab, the panel and the back board is necessary to face outwards.
Post time: Jul-03-2020