Plywood is made of wood-cut veneer or wood to be planed into thin wood, and then glued by adhesive with three or three layers of plate-like material. In order to improve the nature of natural wood anisotropy, so that the plywood characteristics of uniform, stable shape, the production of plywood, the veneer thickness, tree, water content, wood grain direction of production methods should be the same. The number of layers must be odd, such as three or five, seven or nine laminated plates, to make a variety of internal stress balance.
China's relevant national standards, ordinary plywood by tree species divided into coniferous plywood and hardwood plywood, according to the water resistance and durability of rubber layer can be divided into one to four types of plywood. Here is a table in the form of a separate introduction.