Here are some simple ways to select and distinguish the quality of plywood:
First of all, the defects that are not allowed in any grade of plywood are open glue (separation between plywood layers), bubbling (there is a sheet of skin on the front and back that is not glued to the core board, so it bulges slightly). These two defects will directly affect the use of plywood.
1. Panel level
First of all, it is necessary to distinguish the panel grade of plywood.
my country’s plywood panels are divided into four grades, namely special grade, first grade, second grade and third grade. The first-class plywood panel is almost free of defects (individual minor material defects are allowed); the first-class plywood panel is allowed to have individual minor defects (such as needle joints, dead joints, worm holes, cracks, depressions, indentations, etc.); second-class plywood panels are allowed except for a small amount In addition to minor defects, there are also individual slightly serious defects (such as patch, patch, board edge defect); third-class plywood panels allow more defects.
If it is imported plywood, its grade standard can refer to my country’s plywood panel grade standard for grading and grading.
2. Flatness
a) Method: <1> Slide horizontally against the board surface with your hands, and you can feel the flatness of the board surface;
b) Identification: High-quality plywood, because of its good materials and fine workmanship, the board surface will be very flat and feel smooth to the touch. Inferior plywood, due to its poor materials, rough workmanship, and serious internal stacking and core separation, can see the unevenness of the board surface when facing the light, and it feels convex and concave.
3. Core board quality
High-quality plywood, the core board is a whole, good quality, and the seams between the core boards are tight; when the board surface is tapped, the sound is “crisp”.
Inferior plywood, the core board is spliced by broken small core boards, there are many worm holes and dead joints on the core board, the core board has large seams, and the stacking is serious from the core; when the board surface is tapped, the sound is “stuffy”.
4. Strength
Lift one end of the plywood and shake it vigorously for a few times. If the board feels solid, it means that it has good internal quality and high strength; if the board “vibrates” and there is a creaking sound, it means that the board has poor strength. Poor quality plywood or boards with serious structural problems inside the plywood can even break due to violent shaking.
5. Thickness
High-quality plywood, the thickness tolerance between the whole batch of boards is small, and the thickness of different parts of the single plywood is uniform.
Inferior plywood, the thickness tolerance between the whole batch of boards is large, the thickness of different parts of a single plywood is uneven, and the thickness difference of different parts is even greater than 1mm (now the sanding machine is good, and the thickness tolerance is generally small).
6. Smell and environmental protection
If the board emits a pungent smell, it means that the environmental protection of the board is not up to standard; the environmentally friendly plywood emits the smell of the wood itself, which is not irritating. However, if you want to finally determine whether the plywood meets the environmental protection requirements, you must also ask a special wood-based panel organization to conduct the test.
Post time: Sep-04-2022