How is Plywood Made -- Plywood Manufacturing Process

Plywood Manufacturing Process

Wood

1. The plywood manufacturing process begins with processing the

wood at the sawmill. When the raw logs are delivered to the mill, they

are sorted, typically by size and species of tree. Plywood can be made

with a large variety of types of wood. It is often made with pine, fir,

cherry, oak and maple. The uncut logs are then treated with water.

They may be soaked in hot water, exposed to steam or sprayed with

hot water, depending on the setup of the particular mill. Following this

log conditioning, the bark must be removed from the logs to

accommodate the lathing process. Most mills employ a debarking

machine for this process, which minimizes damage to the usable wood.

The logs are then cut to a length appropriate the mill's lathe. The

standard length is typically somewhere between 240 to 270 cm.

Veneer

2. The next phase of the plywood manufacturing process is veneer

production. The logs which are, generally, still hot from the condition

process are then placed in either a veneer lathe or a veneer slicer. The

veneer is sliced off in one continuous piece. Typically, the veneer will

then be rolled onto spools. The veneer will be trimmed to the

appropriate size, which may be performed by hand or by a machine.

The veneer, which is still green wood now, needs to be dried. Different

mills are equipped differently, so the drying process can take two

routes. The veneer may be air dried outdoors or may undergo a kilndrying

process. The kiln is usually a closed system in which the

temperature is constantly controlled to remove water from wood.

Assembly

3. The final phase of the plywood manufacturing process is the

actual assembly of the plywood. The veneer is glued along the edges to

form larger sheets of the veneer for use in plywood production. Large

sheets are then applied with an adhesive and stacked. On the outer

layers, the grain runs the length of the sheet. The grain of the individual

sheets alternates on the interior. The larger glued sheets are then run

through a press (most of which are heated) to dry the glue. Finally, the

wood is subsequently trimmed, sanded if and as necessary and graded

for quality.