Veneer quality control Part 4 : LVL Veneer grading
Special thanks to the original source of http://www.raute.com/lvl-lay-up
Veneer used in the production of LVL is dried, graded and stacked, after which it is measured for moisture content and strength to ensure that it meets strength and stiffness standards and that it is of uniform quality.
Not all veneers are alike and with precise and proper grading, it is possible to optimize the use of this valuable raw material in the LVL end-product. Veneer density, grain orientation and the defects that are present all have an impact on the structural properties of the finished LVL. The LVL veneer grading technology available from Raute ensures that LVL with the best possible strength properties is produced.
A Mecano MVA or DMA moisture analyzer is used to measure the moisture content of the veneer sheets. Veneers containing too much moisture are graded out and only those with an acceptable moisture content proceed to the LVL lay-up line.
Density and strength
Ultrasonic sound propagation time and microwave technology is used to determine specific gravity and modulus of elasticity of each sheet of veneer. Veneers are graded into different categories according to their strength potential.
A Meacno VDA colour camera is used to detect open defects and to analyze the overall visual appearance of each sheet of veneer. This data can be used in conjunction with the strength properties of the veneer to determine the final grade of the veneer and its position in the LVL lay-up.