LVL Handbook EUROPE

1. LVL AS A CONSTRUCTIONMATERIAL

1.6.4 Layup and hot pressing

Glue is mixed on site from resin, hardener and water. In the

manufacture of LVL, phenol formaldehyde resins are mainly

used at approximately 30 kg dry weight per cubic metre of LVL.

Veneer of the required length and proper bonding are

achieved by scarfing a bevel at both ends of the veneer. The

scarfed veneers are fed to the layup line, glued on one side, and

then laid in a staggered configuration (see Fig. 1.40) to form a

continuous billet of LVL. The veneers are normally fed parallel

to the grain direction, although some veneers are laid cross-

wise in certain products. LVL is typically assembled from an

odd number of plies. Special structures can also be produced

to meet specific end use requirements.

Layup starts at the layup table where the veneers are

laid with a staggered edge spacing of approximately 120 mm

(see Fig.19). The resulting staggered jointing maximizes the

strength properties of the LVL.

Figure1.37.

Scarfed veneer end.

Figure 1.38

Layup line principle.

Figure1.39.

Liquid extruder gluing (LEG): glue is applied to the top

of the veneer as it passes on the belt conveyor.

Figure1.40.

Staggered layup ahead of the pre-press.

LVL Handbook Europe