Plywood is made out of thin layers of wood (veneer) glued against each other with perpendicular grain direction. I consider this engineered material is great due to the following reasons:
- Minimal wood expansion and contraction: This is mostly achieved thanks to the opposing forces of the perpendicular grain direction.
- Big working area: The standard size of a plywood sheet is 1.22 m x 2.44 m which is big enough for most applications.
The value of these two characteristics lies in the fact that compared to traditional wood (solid lumber), plywood dimensionality is pretty stable when exposed to everyday humidity and temperature, and that 1.2 meter diameter trunks are not in every corner. This is a great segway for the main topic, plywood manufacturing process.
As mentioned before, plywood consists of a bunch of stacked layers of wood which undoubtedly have to come out of a three. To achieve this, plywood manufacturing companies use huge lathes that spin logs into a large blade, cutting each log into their desired thickness. A more simple way of putting this would be to compare this process with the sharpening of a pencil. The pencil would be the log and the pencil shaving the wood layers.