Blockboard QC Inspection Checklist : Part 4 Grading requirements
A. China Blockboard has good screw holding force, high strength, strong quality, sound absorption, insulation and other characteristics. The moisture content of blockboard is not high, ranging from 10% to 13%. It is easy to process. It is widely used in furniture, doors and windows, jackets, partitions, fake walls, heating hood, curtain boxes, etc.
B. Because the interior is solid wood strip, the requirement for processing equipment is not high, so it is convenient for site construction.
A. Because of the extensive use of uroformaldehyde glue in the production process of blockboard, formaldehyde emission is generally high, and environmental protection standards are generally low, which is why most Blockboard tastes pungent.
B. Most of the chinese blockboard on the market are jerry-built and cut materials. When splicing solid wood strips, the gap is larger. There are holes in the board. If nailing is done in the gap, the nail holding force is basically not grasped.
C. The solid wood strips in the boards are joined together vertically, so the vertical bending strength is poor, and the long-term stress will lead to obvious transverse deformation of the boards.
D. Solid wood strips in Blockboard are different in material and density. They are easy to warp and deform after simple drying treatment. The structure is distorted and deformed, which affects the appearance and use effect.
The technological requirements of blockboard are very high. It not only needs enough site to allow wood enough time for adaptive natural drying, but also requires strict drying process control through drying kiln. Especially after the national compulsory implementation of the limits of harmful substances for decoration and decoration, the adhesives used for large core boards must be improved. This cost alone will increase a lot, and the price of raw materials is still rising. Therefore, due to cost constraints, the market price below 80 yuan of joinery board must not be purchased. Blind pursuit of cheap will bring harm to human health. Many businessmen deceive consumers by various means in order to make profits. Therefore, when choosing and purchasing, they should pay attention to the following points:
(1) The quality grade of joinery boards is classified into first-class products, first-class products and qualified products. Before joinery boards leave the factory, they should be marked with non-fading ink in the lower right corner of the back of each board, indicating the category, grade, manufacturer’s code and inspector’s code of the products; and the category mark should be marked with the words indoor and outdoor. If the information is not clear or clear, consumers should pay attention to it.
(2) Appearance observation, select the board with flat surface, less knot and peeling; observe whether the board surface has warping, bending, bulging and depression; observe whether there is filling and putty around the board. Check whether the core bars are arranged evenly and neatly, the smaller the gap, the better. The width of the core should not exceed 2.5 times the thickness, otherwise it is easy to deform.
(3) Touch with your hand, spread your palm, gently smooth the surface of the wood core board. If you feel burrs pricking your hands, it shows that the quality is not high.
(4) Raise one side of the joinery board with both hands and shake it up and down to listen for the sound of wood tension fracture. Others show that the internal cracks are larger and there are more voids. High quality joinery boards should have a sense of wholeness and thickness.
(5) After sawing from the side waist, observe whether the wood quality of the core is uniform and tidy, whether there are decay, fracture, wormholes and so on, and whether the gap between the solid wood strips is large.
(6) Put your nose close to the cross-section of the joinery board and smell if there is a strong irritating odor. If the woodworking boards emit fragrant wood odor, it means less formaldehyde emission; if the odor is pungent, it means more formaldehyde emission, or do not buy.