Plywood is a type of engineered wood that is made by gluing together several thin layers or "plies" of wood veneer into a flat sheet. The veneer sheets can be made from various wood species, both hardwood and softwood. Some of the most commonly used woods for making plywood sheets include basswood, birch, oak, pine, spruce, fir, mahogany, maple, cherry, and walnut.
To make plywood, the logs are first peeled into thin veneer sheets using a rotary lathe or a slicing machine. The number of layers used in a plywood sheet can vary, with the thickness and strength of the panel depending on the number and quality of the layers used.
The veneer sheets are then coated with adhesive and stacked together, with the grain direction of each layer perpendicular to the layer below it. This cross-grain construction gives plywood its strength and stability.
The stack of veneer sheets is then pressed under high pressure and heat, causing the adhesive to cure and bond the layers of veneer together. After the pressing process, the plywood sheets are trimmed to their final size and sanded to a smooth finish.