Production Technology of Blockboard

Production Technology of Blockboard

Blockboard process requirements:

The symmetrical layer veneer on both sides of the wood core board should be of the same thickness, the same tree species or similar material. The veneer of the same tree species should be selected for surface splicing. The veneer of the superior product board should have smooth surface and be spliced by the whole veneer or two veneers. The veneer of the superior product and the first grade panel should be selected for splicing with similar color and texture. The board should be facing out tightly, and the core board of the same Blockboard should be of the same thickness, the same tree species or similar material.

(2) Core width of blockboard should not be more than 3.5 times its thickness. Core width of blockboard with high quality requirement should not be more than 20 mm. The wider the core board, the larger the deformation of core board when moisture content changes. The longer the core board is, the higher the longitudinal bending strength of blockboard is. However, the longer the core board is, the lower the wood utilization rate is. Along the length direction of the plate, the distance between the two ends of the adjacent two rows of core boards is not allowed to be less than 50 mm, and the distance between the two ends of the same core board (that is, the length of the core board) is not allowed to be less than 100 mm. The side gap of the core board shall not exceed 2 mm, the end gap of the core board shall not exceed 4 mm, and the seamless tape for jointing shall not be used in the interior of the blockboard.

(3) Core boards account for more than 60% of the volume of blockboard, which is closely related to the quality of blockboard. It is better to use softer wood, uniform wood structure, small deformation, small shrinkage, and small difference between tangential and radial shrinkage of wood. No resin leakage, no decay and no corrugation are allowed in the core board.

Core plate production process: drying double-sided planer multi-blade saw cross cutting saw core plate.

Production Process of Blockboard

Fig. 11-4 Production Process of Blockboard

After the core board is glued together, the surface of the board is rough and uneven. The core board is usually processed by pressing, and the core board is processed by machine with high precision. Sanding can be used instead of planing.

The processing technology of blockboard is divided into two kinds: machine and hand. Manual assembly is to insert wood strips into splints manually. The extrusion force of wood strips is small, the splicing is not uniform, the gap is large, the nail holding force is poor, and it can not be sawn and processed. It is only suitable for the sub-projects of partial decoration, such as the mattress of solid wood floors. However, the extrusion force of the machine-assembled sheet is large, the gap is very small, the splicing is smooth, the bearing force is even, and the structure is compact and not easy to deform after long-term use.

(4) The surface of blockboard should be smooth, without warping, deformation, blistering and depression; the core board should be arranged evenly and neatly, with small cracks, and the core board should be free from decay, fracture, wormhole and scar. Some Blockboard Jerry cutting, the gap of the solid wood strip is large, if nailing in the gap, then basically no nailing force. Consumers can look at the sun when they choose, and the cracks in the solid wood strips will be white. If the bonding strength of blockboard is not good, there will be “squeaky” glue opening sound at one end. If the wood odor of blockboard is fragrant, the formaldehyde emission is less; if the odor is pungent, the formaldehyde emission is more.

The quality of joinery boards varies greatly, and they should be carefully checked when choosing and purchasing. Firstly, it depends on whether the core material is compact, whether there are obvious seams and decayed and deteriorated wood strips, and there may be worms in decayed wood strips, which are prone to moth in the future; secondly, it depends on whether there are glue filling and putty filling around, which is generally to make up for internal cracks or holes; thirdly, it is to tap the surface of the board with sharp-mouthed appliances and listen to one. Whether there is a big difference in the lower sound, if there is a change in the sound, it shows that there are holes in the plate. These phenomena will weaken the overall load-bearing capacity of the sheet, and long-term uneven stress will distort and deform the structure of the sheet, affecting the appearance and use effect.

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