The center plate of the blockboard should have the same direction of grain and perpendicular to the texture of the core.
Blockboard core board should be the same species or similar properties of the tree species, water content of 6 to 12%. Core width is not greater than three times the thickness, do not allow a larger crack, holes and so on
Blockboard thickness specifications for the 16,19,22,25 mm quality grade is divided into one, two, three three levels
