Plywood is a kind of board often used in decoration projects nowadays. It is a kind of board that is sliced from different woods and then laminated with glue. It is generally used as structural boards such as furniture and wall hangings. The surface is generally covered with decorative panels for surface decoration and protection, in order to facilitate the use and appearance. The following Hot Press Machine Supplier will show you the structural characteristics and common classification of plywood.
Structural characteristics and classification of plywood
First, the classification of plywood:
1. According to the structure of the board, it can be divided into: plywood, sandwich plywood, and composite plywood.
2. Classified by adhesive properties: outdoor plywood, indoor plywood;
3. Classified by surface processing: sanded plywood, scratched plywood, veneer plywood, pre-faced plywood;
4. Classification by treatment: untreated plywood, treated plywood (such as impregnated preservatives);
5. Classification by shape: plane plywood, formed plywood;
6. Classified by use: ordinary plywood, special plywood.
Second, ordinary plywood
Ordinary plywood was directly called plywood before. Common small classifications of ordinary plywood are:
1. Broad-leaf tree species plywood: tree species include alder, ash, birch, poplar, elm, maple and so on.
2. Plywood of coniferous trees: tree species include masson pine, yunnan pine, larch, spruce, etc.
According to special appearance requirements, there are four grades: first-class, first-class, second-class, and third-class, of which the first, second, and third-class ordinary plywood is the main class.
Structural requirements for plywood:
1. The grain direction of the two adjacent veneers should be perpendicular to each other, which requires the operation of the Veneer Rotary Cutting Machine;
2. The veneer in the symmetrical layers on both sides of the center should be of the same thickness, the same tree species or the same physical new energy, and the direction of production and cut wood grain configuration by the same method should be the same;
3. The center layer, two layers of veneers with parallel wood grain directions, are allowed to be combined into one layer as the center layer. The test plywood is that the two layers of veneers are regarded as one layer;
4. The same layer of surface plate, the same layer of surface plate should be the same tree species, the surface plate should face out.
5. Adhesive tape, non-porous tape for patchwork must not be used inside plywood. If you use it to splice first or second-class panels or repair cracks in first- and second-class panels, you should remove the tape when it is not modified. Paper traces. The total length of tape allowed on a single coniferous plywood surface must not exceed 15% of the length of the board.
6. Veneer thickness. Under normal rod-like conditions, the surface thickness of broad-leaved tree plywood should not exceed 3.5mm. The thickness of the inner panel should not exceed 5mm. The thickness of the inner layer and the surface veneer of conifer plywood should not exceed 6.5mm.
7. Veneer cement, plywood layers of veneer are not allowed to use non-glued goods finger splicing termination.
8. Inclusions, there must be no inclusions in the plywood that affect the use, that is, it does not affect the flatness of the board, does not affect the finish, and does not affect the quality of the glue.
Processing quality and characteristics of plywood:
In terms of processing quality, plywood has right angles and straight edges, and its dimensions and tolerances should meet the requirements.
The characteristics are divided into the meter board and the inner board. According to the appearance grade, the watch board can be a whole veneer, or there can be several boards of equal or different widths spliced together along the edges; the inner veneer should include Arbitrary width splicing veneers that are not spliced allow material defects and processing defects, but do not affect the appearance and applicability required for the use of plywood.