Hardwood Plywood Grading rules and system ,QC checklist
Why Hardwood Plywood?
Hardwood plywood is a panel made up of one or more plies (layers) of medium-density fiberboard or wood veneer (a fine layer of wood that has uniform thickness). Panels can also be made from another type of core attached to a hardwood veneer. There are various benefits to using hardwood plywood, including the following:
• It’s an efficient and environmentally-friendly material. Hardwood plywood is a natural product, and the manufacturing process makes
better use of the material than the lumber manufacturing process.
• It has a beautiful grain and overall appearance. Like other types of wood, hardwood plywood has a natural beauty that’s sure to
complement your existing décor.
• It’s strong and durable. Because of its construction, hardwood plywood is an incredibly strong material that’s sure to last for years.
• Plain Sliced (Flat Cut): This cut is characterized by its consistent cathedral grain pattern of numerous arches and upside-down V’s.
This is the most popular type of face cut, as well as the most inexpensive cutting method.
• Rotary Cut: This type of cut is achieved by using a lathe (a machine that causes a plank of wood to rotate while it’s shaped by a
knife). Rotary cuts have a broad and wild grain pattern.
• Quarter Sawn (Cut): Quarter sawn cuts are made by striking a log at its growth rings, which are wood layers that accumulate at the
bottom of a tree over a certain period of time. This cut simulates the appearance of quarter sawn solid lumber.
There are various species, or types, of hardwood plywood. Here are a few of the most popular species offered at Menards®.
The grade of a panel represents the quality of the lumber. Below is a basic rundown of the various grades of hardwood plywood.
In summary, the lower the face grade, the more knots and defects are allowed in the wood grain.
You’ll likely come across some grades that are followed by a number. For example, you may notice that a panel is rated A1. While the letter A represents the face grade, the number 1 represents the back grade.
1: This is the highest back grade possible for hardwood plywood. It won’t have any large knots, but there may be some color variation
and/or small, tight knots. Any and all worm holes are filled.
2: Use this grade when color isn’t a concern. Larger knots are allowed, but they do not exceed a diameter of 3/4″.
3: This back grade allows knot holes with a diameter of 1″, but it’s still considered to be in sound condition.
4: This back grade is not considered sound. It allows a vast amount of defects.
The core is any substrate that has a wood veneer ply (face or back) applied to it with an adhesive. There are different types of cores, including medium-density fiberboard (MDF), veneer core, and pro-core.
Medium-Density Fiberboard (MDF): This is a stable engineered wood product made from wood fibers. MDF has a smooth, dense, and flat surface that’s free of voids, grain patterns, and knots. MDF cores are the best to use for thin applications, and they also work very well in machines.
Veneer Core (VC): Veneer cores are made by pressing the layers of core veneers into panel sheets in such a way that the layers are adjacent and the grain directions are sloping at a right angle to each other. Veneer cores are fairly light compared to other cores, but they’re incredibly strong. They also exhibit more variation in thickness.
Pro-Core: Pro-core is made of a veneer core interior and MDF cross bands (plies in the panel that have a grain orientation at a right angle to the face and back of the veneer core). The lightweight veneer core interior offers versatility, and the MDF inner plies work well as a laminating surface, because they are smooth, stable, and strong.