Professional articles

: to display the beauty of wood veneer drying technology of humidity control

Juhani Lehto

Juhani Lehto

The product manager

Vaisala

Industrial manufacturing and process
Industrial measurement

Wood is a kind of amazing with unique quality of materials, has a stunning visual appearance.As material, wood is both strong and wide range of USES, at the same time be both renewable and sustainable.

The thickness of the wood veneer is very thin, usually between 0.5 to 3.0 mm, often used to cover different materials of core board or package.Veneer is usually used in furniture manufacturing, cabinets, doors and interior design applications.Usually more popular than real wood veneer, because they are more economical, more flexible, more environmentally friendly.


In the process of manufacturing, veneer in the hot wet air circulation drying in the dryer.This is a demanding process steps;To achieve high quality veneer to make demanding wood products and durable finish, precision dew point control is very important.Drying process could stifle veneer manufacturing efficiency, if not optimized, may become a bottleneck.


Veneer production steps


In the veneer production, the first step is cooking logs.Next, put the wet wood slice, like cut in deli salami.Veneer was sent to hot-pressing drying machine, mobile between the two belts, through high temperature drying machine in turn.Dryer temperature fluctuations between 180-190 ° C, depending on the humidity and moisture content.


In modern dryer, allowed for a separate area strictly control and adjust the internal temperature and humidity of the dryer.From the dry machine, veneer make preparing adhesive, grading, cut to size that matches the plank, and then tied.


Ensure quality by dew point control


Veneer must be fully dry, to flat, flexible, and is suitable for further processing, such as veneer splicing into planks.Veneer moisture content, however, must be in a proper and uniform across the product level, and meets the product specification (different products of different specifications.).The final moisture content must meet strict specifications, otherwise the next processing step "glue" may not be successful.In general, this means the whole batch of discarded completely.


Drying is a delicate process, making the bigger problem is often associated with veneer moisture fluctuations.Too dry the veneer may result in splicing appear problem, because it can become brittle and may fracture.Excessive and dry do not have economic benefits, because it will excessive costs energy and time, led to the decrease of the veneer quality and capacity, and cause unnecessary to take up for drying machine.


The main factors influencing the veneer moisture content including log natural changes in the moisture content, drying air humidity, drying machine and filling of different grades, and drying temperature change.


Therefore, manufacturers will benefit from the on-line measured data, this for control of drying process laid a new foundation.


Installed directly without sampling system


Humidity within the dryer use visa pull DRYCAP ® dew point transmitter (such as visa DMP5, DMP6 and HMP7) measurement, the transmitter directly installed in different areas of the dryer.Don't need to use complex sampling system.Heated probe technology can reduce the risk of accumulating condensate on the sensor.When DRYCAP ® sensor be affected with damp be affected with damp, it can dry quickly and restore fast response.


Measurement data will transfer to the operation of the dryer system, the operating system to connect the control of drying machine running the required information.You can from the operator position of remote monitor based on programmable logic controller (PLC) to access the data in the system, and it can change the touch screen operation procedures.


The quality is supreme


To continue production in conformity with the specification veneer, must ensure that the drying process can be measured is adjustable, and can be measured by the quality of online data analysis process of heat and humidity.In addition, we can improve energy efficiency, yield and quality, for the manufacturers and customers to bring satisfactory results.

Go to the wood drying page

Juhani Lehto

Juhani Lehto

High-end product manager

Visa,