What Are The Losses in The Production Process Of Plywood

In the whole production process of plywood, the drying of the core board, the finishing of the blanks, the hot pressing, the trimming, and the sanding have an impact on the wood loss, which is divided into tangible loss (with processing residue) and invisible loss (drying shrinkage and compression) . Timber loss is related to factors such as log species, log specifications, equipment conditions, process technology, and finished board specifications.

Core board drying: The core board after rotary cutting has a high moisture content, and the core board must be dried to meet the requirements of the gluing process. The size of the wood becomes smaller after drying, which is called drying shrinkage. As the moisture content decreases, the length, width and thickness of the core will shrink. The shrinkage loss is related to the tree species of the core board, the moisture content of the core board and the thickness of the core board. Dry shrinkage loss rate is generally 4% to 10%.

Assembling of blanks: The finishing of blanks includes cutting, assembling and repairing. Cut the dried strip-shaped core board and zero-piece core board into specification core board and splicable core board, the narrow strip core board is spliced into a whole core board, and the defective core board can be repaired to achieve the process. Quality requirements. The amount of waste core board generated in this process is mainly related to the operator's familiarity with the core board standard and the quality of the core board. The loss rate is generally 2% to 4%.

Hot pressing: The glued slabs are firmly glued together by a certain temperature and a certain pressure. During hot pressing, as the temperature and moisture content of the slab change, the wood is gradually compressed, and the thickness of the slab gradually decreases. This loss is compression loss, which is related to the hot pressing temperature, unit pressure, hot pressing time, tree species and moisture content of the plywood. The loss rate is generally 3% to 8%.

Trimming: Cut the hot-pressed wool board into specification boards. The amount of cut edge waste is related to the processing allowance of the plywood and the size of the width. The larger the width of the plywood, the smaller the cutting edge loss rate, generally 4% to 6%.

Sanding: Sand the surface of the plywood to make the surface smooth and beautiful. The waste generated in this process is sanding powder. When the quality of the core board is good, the sanding amount is small, and the sanding loss rate is generally 2% to 5%.