Usually plywood slightly curved pressed by clamping it between a pair of hot molds. Manufactured from plywood and shaped blanks for cabs and cabins, aircraft parts etc. Manufacture of adhesives prepared in mechanized mixers and the production of plywood served in the grooves of a pair of adhesive rollers (made of metal or hard rubber), which rolled from both sides of every second layer of veneer or lumber. Then the packets missed glue veneer clamped and glued into a hydraulic or pneumatic, and sometimes in the screw (which is the least desirable) presses. If the glue is applied at room temperature (21 to 27 C), then glued the plywood sheets are usually added in piles and kept them in 6 hours or more to harden the glue. Pressing the plywood with synthetic thermosetting adhesives most efficiently at elevated temperatures – hot-gluing, when ready to receive sheets only takes a few minutes. To this end, hydraulic presses are made in the form of tiered toolbox plates with a steam heated from 120 to 150 C between each pair of panels laid compressible package – the future sheet of plywood.

There are press with electrically heated tool resistors or high-frequency electric field. For production of curved plywood flat tool press plate supplied with the corresponding pair of metal molds. In the manufacture of fancy plywood complex profile of one of the mold is injected in a volume sealed envelope, which puts pressure on all fronts on one side of molded plywood, placed on a rigid, fixed mold. For the polymerization of resin adhesives with the use or the heated mold, or in the injected volume of pumped hot water vapor. Since yielding of wood increases as it is heated, it is difficult to manufacture high-quality profiled plywood not apply adhesives, solidifying at room temperature.

Produced various types of plywood: lined with kraft paper, impregnated with and without it; suitable for external cladding and veneering. Metallized plywood, ie, the plywood with layers of metal, is used where operating conditions require a strong and dense surface, such as a truck, or where due to the metal strip increases durability and fire safety material. Produced and high-density plywood. Usually they are drawn from lists of layers bakelized veneer and pressed by hot gluing. The share of plywood this type may reach 1.3, and wood a plywood significantly compacted during hot pressing.

Sorry, comments are closed.