There are several classifications of plywood depending on various factors. When choosing plywood, it is necessary to know the types of plywood and which one is better for a certain field of application.
1. Depending on the grain direction of the upper veneer layer, plywood is divided into long-grained and cross-grained. Cross-grained plywood is distinguished by the perpendicular grain direction of the outer veneer sheets to the largest side of the plywood sheet. In long-grained plywood, the grain direction of the outer veneer sheets coincides with the largest side of the plywood sheet. As a rule, in the production of plywood, veneer sheets are alternated with the long-grained and cross-grained grain direction. This provides the strength of the plywood. A special lay-up is possible at the request of the customer.
2. According to the degree of mechanical surface treatment, plywood is divided into: unsanded, sanded on one side and sanded on both sides.
3. Depending on the type of wood used for the manufacture of plywood, there are: birch plywood (from hardwood veneer), coniferous (from softwood veneer) and composite plywood. Plyterra Group plants produce 100% birch plywood. At the request of the customer, veneer of other hardwoods can be used.
4. According to the surface grade, depending on the appearance of the outer layers, the following main grades are distinguished:
1) Grade I without external defects
2) Grade II with a small surface restoration
3) Grade III for the manufacture of structures hidden from view (the third grade includes what is not included in the second)
4) Grade IV with various manufacturing defects
