LVL Handbook EUROPE

1. LVL AS A CONSTRUCTIONMATERIAL

Figure1.35.

Composing principle.

Figure1.36.

Green veneer composing line.

The target moisture content is below 5%. Automatic regulation

maintains the speed, temperature and humidity inside the dry-

er at an optimal level. The energy required to dry the veneer

can be produced from the mill’s own by-products.

A fully automatic machine vision system analyses veneer

defects, such as knots, splits, breakages, micro-splits, decay,

resin pockets and discolouration, at process speed. The image

data is analysed in milliseconds and used to stack the veneers

into different bins at the stacker. The dried veneer is measured

for moisture content to ensure the target moisture has been

achieved. Density measurement and strength grading of the

veneer are also carried out based on radio frequency analysis

and ultrasonic propagation time.

Veneer pieces of different sizes – i.e. ‘randoms’ – can be

composed into veneer sheets of required width. Composed ve-

neers are used as core veneers. The aim is to increase veneer

yield by maximizing the use of peeled material. Randoms can

be collected from peeling line and broken veneers from the

drying line. Veneer can be composed green or dry. At the com-

poser, the randoms are glued or taped together to form full-size

veneer sheets for LVL production.

LVL Handbook Europe