Plywood is classified by application into general-purpose plywood (for wide-ranging uses) and special-purpose plywood (for specific functional requirements).
Quality requirements for plywood cover three aspects:
appearance grade, dimensional specifications, and physical and mechanical properties.
A product is qualified only if it passes all three inspections; otherwise, it is deemed unqualified.
Plywood delivered from the factory must be accompanied by a product quality certification issued by the manufacturer’s quality inspection department, indicating the type, specification, grade, bonding strength, moisture content, and other parameters.
(1) Dimensional Specifications of General-Purpose Plywood
Plywood thickness includes:
2.7 mm, 3.3 mm, 4.5 mm, 5.5 mm, 6 mm, etc.
From 6 mm onward, thickness increases in increments of 1 mm.
Plywood thinner than 4 mm is classified as thin plywood.
Common thicknesses: 3 mm, 3.5 mm, 4 mm.
Other thicknesses shall be produced by agreement between supplier and purchaser.
(2) Appearance Grade
Based on visible natural wood defects and processing defects on the finished surface, general-purpose plywood is divided into four grades:
Premium Grade, Grade I, Grade II, Grade III,
among which Grades I, II, III are the main grades for general plywood.
The face veneer of all four grades shall be sanded or scraped smooth;
for special requirements, it may be unsanded, or sanded on both sides.
Sanded plywood refers to plywood whose surface has been finished by a sander or scraper.
Grading is generally determined by visual inspection of permissible defects,
depending on allowable natural defects, processing defects, and requirements for splicing.
