LVL Handbook EUROPE

Figure 1.22.

The LVL production process.

1. LVL AS A CONSTRUCTIONMATERIAL

1.6 PRODUCTION OF LVL

The LVL production process is subject to strict quality stand-

ards and audited by inspectors to ensure the final product is

safe to use and meets the specified end use requirements. LVL

is made by gluing and layering wood veneers to produce a ho-

mogenous wood panel. The process distributes any natural de-

fects in the wood raw material evenly throughout the product,

eliminating any individual points of weakness. The following

simplified production diagram illustrates the LVL production

process inside the mill.

Veneer logs are delivered from the forest to the mill at a

specified length. The logs are debarked, conditioned, and cut

Figure 1.21.

Composition of LVL, from veneer mat to cut-to-size

panel.

Figure1.23.

Log use distribution by volume: LVL and by-products

(incl. shrinkage and compression losses).

Figure1.24.

Harvesting of logs.

to blocks. On the peeling line, the veneer block is turned to

produce a veneer mat. The green veneer is clipped to size and

then dried, graded and composed when necessary. Glue is then

applied on the top side of each veneer and the veneers are stag-

gered to form a LVL billet. In hot-pressing, the glue cures and

binds the veneers together. Finally, the formed LVL panel is

edge trimmed or cut to size (e.g. to a specific beam width) be-

fore stacking and packaging.

For every cubic metre of LVL about 2,5 m

of logs (meas-

ured over bark) are processed, which is a similar raw material

yield to plywood production. The LVL production process thus

delivers more by-products than final product. None of these

by-products go to waste. They are sold and used in pulp, fibre-

board and other wood-based products, for energy production,

and for decorative purposes. Glue residues are reused inside

the mill.

1.6.1 Logs to blocks

To maintain high raw material quality, veneer logs are trans-

ported to the LVLmill immediately after harvesting. At the mill

site, the log piles are sprayed with water to avoid drying and

cracking and attack by pests.

LVL 01, Figure 1.20

LVL

Green chips

Bark

Drying shrinkage

Veneer handling

Sawing dust

Core

Compression

10% 15% 20% 25% 30% 35% 40%

PRODUCT AND BY-PRODUCTS SHARE FROM LOG VOLUME

LVL Handbook Europe