Plywood is a panel product that is manufactured by gluing thin sheets of wood, called veneers, together under heat and pressure. The final product is used in variety of applications, often in construction. Plywood is a comparatively high value product, especially when it is used in demanding applications where the quality of the product is very important. Plywood has good strength properties relative to its weight. However, the deformation, e.g. the warping of plywood is an issue. Warping and other dimensional stability problems are very typical in thinner plywood panels, especially when they are subjected to variable humidity conditions. The stability of plywood is very important criterion for the use of plywood in some special applications. There are some standards that are used to determine these properties in panel products, e.g. EN 13647 (Wood and parquet flooring and wood panelling and cladding. Determination of geometrical characteristics) and EN 910 (Wood and parquet flooring and wood panelling and cladding. Determination of dimensional stability). The dimensional stability tests are based on humidity cycle testing. This poster discusses the standards, measurement systems and also the problems associated with the dimensional stability and warping of plywood. Some measurement data and figures which describe the problem will also be included.
Keywords: plywood, wood based panels, deformation of plywood, dimensional stability
Authors
Paajanen O.
Department of Forest Products Technology, School of Chemical Technology, Aalto University. Aalto, Finland
Mäki V-M.
Kairi M.
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