The veneer after being cut by the rotary cutting machine （veneer peeling machine）contains a large amount of moisture. In the production of plywood, the veneer generally requires a lower moisture content. Therefore, the veneer after rotary cutting should be dried by a veneer dryer to make the moisture content of the veneer meet the production requirements of each plywood manufacturer. The moisture content of the veneer processed by the veneer dryer should be uniform, and the deviation should not be greater than 1% -2%. The moisture content of the veneer is large, which will easily cause defects such as degumming, bulging, and surface glue penetration.
What are the characteristics of veneer drying?
When wood is heated in hot air at a certain temperature, first of all, the moisture on the surface of the veneer is evaporated to reduce the moisture; secondly, the moisture inside the wood moves to the surface of the veneer, so that the moisture content gradient and water vapor pressure gradient inside and on the surface . Under this effect, water vapor began to diffuse along the veneer cell cavity through the pores and pores in the pore membrane, from inside to outside. Therefore, the drying process of wood is determined by two factors, surface evaporation and internal diffusion. If the internal expansion effect is more severe than the surface evaporation effect, the drying rate is mainly affected by the surface evaporation rate; otherwise, it is mainly affected by the internal diffusion effect.
The veneer after rotary cutting has its own characteristics. Because the thickness of the veneer is small, the area is large, and the water travel distance is short, and the wood becomes slack after being rotated and some fibers are cut, the spreading resistance inside the veneer decreases. Although the drying speed of the veneer is determined by two factors, surface evaporation and internal diffusion, when the veneer is dried, the surface evaporation area is large, the internal expansion resistance is small, and the surface evaporation and internal diffusion are very vigorous. Therefore, when the veneer is dried, a high temperature and rapid drying process is usually selected, so that the veneer is not easily deformed.
mesh bag dryers roller veneer dryers vertical veneer dryer
Veneer drying is divided into natural drying and machine drying. The former is more suitable for small-scale production, and the latter is more suitable for large-scale production. Among them, there are three types of dryers commonly used by customers: mesh bag dryers, roller veneer dryers and vertical veneer dryers. The dryer is a very important plywood machine. Choosing the right machine according to your own production requirements can improve production quality and production efficiency.