Plywood QC Inspection Checklist : Part 4 Number of Plies (Layers )
The quantity of the plywood plies normally affect the final quality of the plywood ,especially the Odd and even construction .As traditional manufacturing production ,plywood always have Odd plies ,for example ,18mm plywood has 11 plies or 9 plies ,5 plies or 13 plies ,not 10 or 12 plies …
In China ,some manufacturers in order to save manufacturing costs ,they Invented one way to make even number plies ,such as 10 plies ,8 plies ,or 12 plies to make plywood .
The difference of Odd and Even numbers ,only affect the warpping problems (also called balance ) .There is usually an odd number of plies, so that the sheet is balanced—this reduces warping. Becauseplywood is bonded with grains running against one another and with an odd number of composite parts, it has high stiffness perpendicular to the grain direction of the surface ply.
In China ,traditional production ,the inner core plies
18mm 11 plies ,13 plies ,9 plies
15mm ,9 plies ,11 plies
12mm ,7 plies
5.2mm 3 plies
2.7mm 3 plies and 4 plies