The quality of a piece of plywood directly affects its use and value. Therefore, we must check the product quality according to national standards in order to achieve a unified understanding. Let’s check: the dimensions of the board, the appearance quality and the physical and mechanical properties.

I. standard plywood dimensions

Check whether the thickness, length, and width of the board, the two diagonal lines, and the warpage degree meet the requirements of national regulations, especially the length and width. The Tolerance is usually ±0.5mm or ±1mm.

by the way, how do we check the warpage rate?

Test method: at least ten pieces (pieces) of products of each specification shall be sampled for inspection, the front and both ends of the product to be tested shall be fixed with chalk line, the length L of both ends of the product to be tested shall be measured with steel tape, the maximum distance h between chalk line and plate shall be measured with vernier caliper, and the calculated warpage = H / lx1000 ‰; the calculated data shall be recorded.

I I.how to buy plywood sheets

Buy according to the purpose you need it for. For indoor furniture, which isn’t going to be exposed to water, use BWR grade (moisture resistant), for any furniture which has a chance of getting in contact with water often such as kitchen furniture, use BWP(boiling water Proof) / Marine Ply. You can test a marine ply for its waterproof characteristic by taking a cut sample and boiling it in a pressure cooker for 7 whistles. The layers of the ply shouldn’t delaminate in a genuine case as per standard marine ply. If it splits, its probably not a marine ply.

I I I. physical and mechanical properties.

The national standard stipulates that the moisture content and the bonding strength are two, and they are the two most important. The national standard stipulates that when using resin adhesive, its moisture content should be controlled in the range of 6-14%, and the bonding strength should be controlled in the range of 0.7-0.8Mpa.

When inspecting defects, some defects will affect the appearance, such as joints, cracks, decay, patches, plate edge defects, etc., depending on the occurrence of more or less, as long as it is within the range allowed by the standard, it is just a product degradation. However, some defects, such as bubbling and delamination, which directly affect the strength of the product, are not allowed at any level. Some bubbling and layering, if the area range is large, it is easy to observe visually, but the area range is small, and it is not easy to observe, you can use a small wooden stick to beat anywhere on the board, such as the board echoes crisp and loud, then It can be judged that there is no bubbling or delamination. If the echo is deep or mute, it indicates bubbling or delamination.

Therefore, the quality of plywood must be judged from the above three aspects.