_______ determines the thickness of plywood board.
🪵 How Plywood is Constructed
Plywood is an engineered wood panel made from thin sheets of wood veneer, known as plies. These plies are glued together with their grain direction rotated 90 degrees to the adjacent layer (cross-graining). The entire panel is then pressed under heat to form a strong, stable board.
The final dimensions of the plywood board are determined by different factors. The length and width are determined by the size of the veneers, while the thickness is a direct result of how the plies are stacked.
📝 Detailed Analysis of the Options
(a) plie width, (b) plie length, (c) plie area
These dimensions define the surface area or the "footprint" of the plywood board. They determine how large the sheet is, but they do not determine how thick it is.
(d) number of plie layers
This is the correct answer. The thickness of a plywood board is the sum of the thicknesses of all the individual plies (or veneers) that are glued together. Therefore, the number of plie layers is the primary factor that determines the final thickness. A 3-ply board will be thinner than a 5-ply or 7-ply board, assuming the individual plies are of similar thickness. This layering technique gives plywood superior impact resistance and uniform strength in all directions, unlike ordinary wood which is much stronger along the grain.
📊 Typical Plywood Specifications
| Parameter | Determined By | Typical Dimension |
|---|---|---|
| Thickness | Number and thickness of plies | 3 mm to 25 mm (or more) |
| Width | Width of veneers | 90 cm to 120 cm |
| Length | Length of veneers | 210 cm to 240 cm |
💡 Study Tips
- Think of a Stack of Paper: The thickness of a stack of paper depends on the *number of sheets*, not the length or width of a single sheet. Plywood is the same; its thickness depends on the *number of plies*.
- More Plies = More Thickness & Strength: A greater number of layers directly translates to a thicker and generally stronger and more stable board.
- Dimensions vs. Thickness: Be clear on the difference. Length and width are the 2D surface measurements. Thickness is the 3rd dimension, created by stacking the plies.