Plywood craft
Log sawing
After the domestic or imported logs are pulled to the factory, they should be sawed according to the length and quality required by the process, and the cut wood should be the length of the finished plywood plus the processing allowance. For example, we need 1220*2440mm finished plywood, and the length of wood segment is usually 2600mm or 1300mm.
Veneer peeling
The most widely used plywood production is the veneer produced by the rotary cutting method. Clamping of the two ends of the wood segment by the rotary cutting chuck will cause the loss of the end. The wood core cannot be peeled, and it is generally concentrated and then processed.
Veneer sorting
To sort out the peeled veneer or the purchased veneer, we usually select and grade manually. If the surface is complete and no pits are found, it is a special grade. If the surface is complete but a little bit, it is grade 1. If the surface needs to be repaired more, it is grade 2. The inferior veneer is grade 3, which is generally returned or digested.
Veneer drying
The veneer after peeling has a high moisture content, and the veneer must be dried to meet the requirements of the gluing process. According to the thickness of the veneer, choose a mesh belt or a tumble dryer. After the veneer enters the heating chamber, the temperature of the hot oil or water vapor released should be kept stable. The moisture content is relatively consistent. The cooling chamber is used to facilitate the cooling of the dried veneer and reduce the phenomenon of moisture returning.
Veneer finishing
After a few days of storage, the veneer is cut, spliced and repaired. The dried veneer is cut into specification veneer and splicable veneer, the narrow-side veneer is spliced into a whole veneer, and the defective whole veneer can be repaired to meet the quality requirements of the process. For the paneling effect, it is necessary to use an edge trimmer to trim the edges of the thin boards before paneling. When the splicing machine is working, it needs multiple or different models to work together. For example, our factory is: a veneer horizontal splicing machine for panel splicing, a veneer vertical splicing machine for four splicing for butt splicing (9 layers of panels) , Three veneer vertical splicing machines and six splicing machines are used for butt splicing (inner long and medium boards) and three veneer horizontal splicing machines are used for splicing glued boards. After the defective veneer is repaired, it will be matched and stored.
tissue culture
The whole piece of level 2 horizontal stitching is glued for spare use, the level 1 vertical stitching (four stitches) long and medium panels and the 2nd level vertical stitching (sixth stitching) long and medium boards are dry-laid. According to the principle that the wood grain directions of adjacent veneer layers are perpendicular to each other, the number of layers is determined according to the thickness of the finished plywood. The number of veneer layers is an odd number, generally three to thirteen layers. Common three plywood, five plywood, nine plywood, and thirteen plywood (commonly known as three plywood, five plywood, nine plywood, thirteen plywood in the market) plate). The outermost front veneer is called the panel, the reverse is called the backplane, and the inner layer is called the core board.
Cold Press - Hot Press
The glued tissue cultured slabs are glued to a certain thickness by a certain pressure of a pre-pressing cold press. After the core is repaired, the pre-pressed wooden boards are put into the hot press, and the hot press is firmly bonded together by a certain temperature and a certain pressure. During hot pressing, with the change of the temperature and moisture content of the slab, the board is gradually compressed, and the glue is fully exerted, so that the board is tightly bonded.
Trimming, scraping - double-sided fixed thickness sanding
After hot pressing, the wool board is initially formed, and the edges of the board are uneven. We need to cut the edge of the hot-pressed wool board into a specification board. Scrape the ash, and after storage, the surface of the plywood needs to be sanded to make the surface smooth and beautiful.
secondary tissue culture
After the special-grade panel is glued to the surface of the rough board and then cold-pressed and hot-pressed again, the surface is polished by hand and sanded again.
Veneer processing
Lay the veneer on the top and bottom of the board again, after cold pressing and hot pressing again, manually trim the edges with sanding and sawing, and inspect and pack after completion.