Process of Manufacturing Plywood
Wet storage is the most commonly used preservation method for timber. Wet storage of wood is applied to protect against fungal and insectal attacks and to prevent checking. It can be assumed that the success of wet storage should only be dependent on the relationship between evaporation from wood and the amount of water applied on the roundwood piles. If the roundwood during the summer is stored unprotected, or if the sprinkling intensity is too low, the roundwood will be exposed to damage connected with drying-out. The main risks then are blue stain, beetles, development of end checks and debarking problems. On the other hand, if too heavy sprinkling intensities are used or if the wet storage period is too long, other negative effects on the quality of roundwood may occur. These effects are bacterial damage in wood, bark stain and negative influences on the environment.
Converting a round log into rectangular timber is rather inefficient, and only about half of the log volume becomes sawn timber. t
he remainder usually ends up as slabs, chips or sawdust, which become feedstock for panel products or energy production. Diameter and shape (sweep, taper, ovality) do not usually limit the kinds of processing systems which can be used. Sawing of logs is the most common processing method used. Peeling and slicing and the manufacture of a range of reconstituted wood products are increasing in importance. excellent results have been obtained with bandsaws, circular saws, frame saws and chipper canters in all the common sawmill configurations.
The Next step of manufacturing process is peeling the log. The log sections, which show the marks of the debarking knives, are fed into the lathe loader where the log revolves around on a huge lathe against a long cutter blade which is reduced to a 6-inch core or sawed into lumber or chipped.
Following the peeler process, the next step in the manufacturing process of plywood is taking the logs and making them into a continuous ribbon of wood. the cutting edge of the lathe is forced against the spinning log. the wood is unwound in a continuos ribbon varying in thickness depending on how its used.
The standard size for the pieces of wood to be cut in 4' x 8'. The thickness of the plywood will be determined later when the sheets are glued and pressed together to a varying thickness of which 1/4 to 3/4 is the most common. As the sheet emerges from the peeler it is scanned automatically and then it is stacked geen and is prepared for the transferring to the drying ovens.
The next most process is to dry the pieces with mechanical oil heated drying. During this process, the wood panel surface is contact with thermocompressor and rise to a very high temperature, waters in the wood panel become steam, there will be a temperature between the panel surface and the inside.
Hot pieces are the dried down for further process towards life cycle of process of plywood manufacturing.
Balanced Construction & Gluing
The next step in making of plywood is to gluing of the plies together in order to determine the desirable thickness of the plywood sheet. The glue is spread on alternate layers of lumber by passing between pairs of grooved metal or hard rubber rollers.
When heat is used the glue hardens within a few minutes. The glue solidifies as the plies are pressed together and once the pressure is released, the boards are considered dry.
Plainning & Fininshing
Lastly the sheets have to go through a process that gets them ready to be shipped out for market. This process involves trimming, sanding, plaining and fininshing the sheets. This process also takes the sheets down to the proper size that is desirable to the consumer.