LFPDC Publications :: Fact Sheets :: # 6

Softwood Plywood Manufacturing in Louisiana

Peeling logs into veneer and assembling the veneer into plywood is an efficient method of making large, strong panels for building materials and other purposes.

Since southern pines make excellent raw material for the manufacturing of plywood, Louisiana plays an important role in that industry. Following are the plywood mills in Louisiana and some publicly known data about them (1994-1995 data):

Plywood production is commonly measured by square feet, 3/8ths inch basis. For example, a 4' by 8' by 3/8" panel contains 32 square feet. A 3/4" thick panel contains 64 square feet. Plywood is also classified by grade, usually A, B, C, D or reject. Grade is dependent mostly on the visual quality of veneer.

An "A" grade sheet of veneer has virtually no defects. An "AB" panel contains an "A" grade veneer on one face and a "B" grade veneer on the other face. CDX is a very common grade of southern pine plywood that is used in the building construction industry inside walls and under roofing. One face is grade "C", the other face is grade "D", and the "X" denotes that the panel is suitable for exterior use; that is, the veneer layers will stay glued together if the panel gets wet.

This is the typical Material Flow in a plywood mill:

• Log Yard - receiving & storage.
• Merchandiser - de-barks & cuts logs into 8' blocks (+ trim).
• Conditioning chambers or Soaking vats - heat blocks to about 130 degrees F. so that they will peel better.
• Rotary veneer lathe - peels log into a ribbon of veneer (8' wide + trim).
• Clipper - clips veneer into sheet size (4' + trim), half sheets (2') or random widths (< 2').
• Green chain - stacks the (green) veneer. Full sheets are typically stacked automatically, others by hand. Fishtail veneer (veneer that is literally half good) is stacked separately. Later the stack will be cut in half, and the bad half thrown away. The good half (4' x 4') is used for core stock (middle of the plywood).
• Veneer driers. Veneer stacked according to grade. Patch knotholes in upper grades.
• Lay-up line (layers of veneer glued together).
• Hot press.
• Panel trimmer.
• Depending on grade of plywood -- sanding and filling.
• Shipping.