The lack of unified terminology on the market of solid wood board materials for furniture production can mislead not only the buyer, but also the woodworking specialist. To reduce the cost of production, under the guise of joinery boards consumers are often offered other products that do not provide the same performance properties.
The purpose of the process of gluing wood materials is not only to increase their linear dimensions, but also to ensure the form stability of finished structures during operation.
Gluing lamellas of solid wood along the edges with their subsequent facing allows to create wide panels, which are used in the furniture industry and have a number of advantages as compared to chipboard and fiberboard panels. Properly made, laminated solid laminated wood materials are less susceptible to moisture exposure and less prone to warping than other wood materials. Let us find out together what compulsory elements a joinery panel must be made of, and how the producers guarantee its form stability and resistance to external influences.
Classic joinery board is a standardised wood-based material consisting of three layers. The middle layer consists of parallel, glued or unglued bars. On the front and back sides the lamellas are lined with one or two layers of veneer or glued plywood, observing the perpendicular direction of wood fibres in the adjacent layers. Gluing several layers by thickness does not increase the thickness of the product, but creates a composite material of increased form stability.
For making the inner layers of joinery boards boards boards, bars or lamellas are used – planed lumber or parts designed to be glued into a multilayer glued element. The width of lamellas should be no more than 40 mm for boards of standard precision, and 20 mm for boards of increased precision. The smaller the linear dimensions of the boards, the less influence of anisotropy on their performance properties, which ensures dimensional and shape constancy during operation. When used in layers of lamellas, glued along the length on a toothed spike, the form stability of the boards and, accordingly, the finished products is further increased.
Three-layer construction of the panel prevents warping, since the stresses in the wood arising from shrinkage and swelling are restrained by the adjacent glued layers.
Furniture boards are produced in thicknesses of 16 to 30 mm, widths of 1220 to 1525 mm and lengths of 1525 to 2500 mm.
A single-layer furniture board made of lamellas glued together at the edges on a smooth joint is not a joinery board, as there is no cross-gluing of the layers. During use, its shape is capable of changing, which can even lead to the destruction of glue joints. The nature of warping can be different and depends on the direction of the fibers in adjacent lamellae. Even the use of radial lamellas alone cannot completely prevent the warpage of such structures.