How is plywood made?
Plywood has an almost infinite number of applications in manufacturing due to its durability and nice finish. It is made of three or more layers of wood, bonded with adhesive for strength. It is used for everything from construction to furniture to DIY projects, but how is it made? Here we take a look at the main steps in the construction of plywood, from its raw state to the plywood for sale that we see online and in hardware shops.
The raw materials
Plywood can be made from any number of types of trees, from pine, spruce and cedar to mahogany, ash and maple. These are all woods with strength and durability, as well as an aesthetically pleasing colour and grain. The logs from these trees are debarked, and then go through a conditioning process which ensures that they produce a good quality veneer when they go through the next stage. This conditioning process usually involves steaming or submerging the logs in hot water to soften them, and can take anywhere from 12 to 40 hours to complete.
Making the veneer
The logs are then peeled on a lathe to produce long sheets of wood. If there are any defects, then these are clipped out, producing a smaller veneer – these can be joined together with other small sheets to make a regular-sized one. Once the sheets have been cut, they must then be dried to avoid shrinkage once they have been glued together into the final product. These sheets can be used immediately or stored for later use. They are sorted into face, core and back sheets, according to appearance and quality – this makes it easier to compose the layout.
Forming the finished product
The sheets are passed through a glue spreader which evenly applies a layer of adhesive, and the sheets are stacked with the back at the bottom, the core in the middle and the face on top. The assembled sheets are then fed into a press which compresses and heats them, curing the adhesive and ensuring good contact between the layers. Once this process is complete, the sheets are cut to size and the higher grade sheets sanded for a good finish.
Preparing for sale
The sheets are stamped with a trademark which tells the buyer about the plywood’s grade, mill number, exposure rating and other information. A random sample is taken for testing to ensure the quality of the finished product, including both mechanical and bonding strength, and formaldehyde emissions. A quick visual check and the plywood is ready to be shipped out for sale.