How to distinguish the advantages and disadvantages of plywood
In addition to appearance, internal quality is more important in selecting plywood. Plywood, also known as “splint”, has three splints, five splints and seven splints. Generally speaking, it is better to make furniture with three splints: Fraxinus mandshurica, basswood and Liu’an. The following points should be grasped when selecting:
(1) There are differences between the positive and the negative sides of the splint. When selecting, plywood should have clear grain, smooth and smooth front, not rough and flat.
(2) Plywood should not be damaged, damaged, wormwort, nail row holes, dead joints, burrs and grooves.
(3) No degumming of plywood;
(4) Some plywood is made of veneer glue with two different patterns. Therefore, when choosing plywood, attention should be paid to the tight joint and no unevenness. Especially a plywood should not have two different lines, otherwise it will hinder the rational use, cause waste and affect the beauty of furniture.
(5) When choosing splints, attention should be paid to choosing non-dispersible splints. A 50 cm stick can be used to lift plywood and tap each part lightly. The sound is symmetrical and crisp, basically equal to the inner panel. If the mute sound of “shell” is emitted, it is likely that the internal quality problems caused by degumming or bubbling will occur. This kind of board can only be used as lining board or top and bottom board, not as fabric.
(6) When choosing splints, attention should be paid to the coordination of wood color and furniture paint color.
(7) Generally, there are grade marks on the surface angle of regular plywood for reference.
The quality of a plywood has a direct impact on its use and use value. Therefore, if we want to do a good job of checking the product quality, we must carry out according to the national standards, so as to achieve a unified understanding. Plywood can be inspected from three aspects: size, appearance quality and physical and mechanical properties.
1. Dimensions: Check whether the thickness, length and width, two diagonals and warpage of the board meet the requirements of the state, especially the length and width. The size of the board can only have positive tolerances, and negative tolerances are not allowed.
2. Appearance quality: According to the national standard, ordinary plywood is divided into four grades according to material defect and processing defect: special grade, first grade, second grade and third grade. The last three grades are the main grades of ordinary plywood. Each grade is determined by visual inspection according to the allowable defects on the panel, and the allowable defects and processing defects of the backplane and inner veneer are limited.
3. Physical and mechanical properties. The national standard stipulates moisture content and bonding strength, which are the two most important items. The national standard stipulates that when using resin adhesives, the moisture content should be controlled in the range of 6-14%, and the bonding strength should be controlled in the range of 0.7-0.8 Mpa.
When inspecting defects, some defects will affect the appearance, such as live joints, cracks, decay, patches, edge defects, etc. According to the occurrence of more or less, as long as within the allowable scope of the standard, it is only product degradation. However, some defects directly affect the strength of products such as bubbling, stratification and so on, which is not allowed at any level. Some bubbles and layers, if the area is large, can be easily observed visually, but the area is small and difficult to observe, can be tapped anywhere on the board with the help of a small stick, if the board echoes clear and loud, it can be judged that there is no bubbles or layers. If the echo is silent or mute, it indicates that there are bubbles or layers.如无特殊说明，文章均为本站原创，转载请注明出处。If there are no special instructions, the articles are original, if you want to use or reproduce, please indicate the original source www.plywoodinspection.com,If you find that our articles infringe on your copyrights and interests, please email us at email@example.com in time and we will delete it at the first time.