Kiln loads are bursting with data
In this series of blogs, our experts explain the different stages in a drying kiln project and other important elements in the world of kilns as part of sawmill operations. This time, Veijo Malmi tells about drying kiln automation from the data and data transmission perspective.
In the sawmill industry, data harvesting starts already when the foot of the tree is detached from the stump in the forest. Tree height, volume in cubic metres, felling location and a lot of other information is harvested immediately for each tree. Following that and after many interim stages and measurements, the load of sawn goods is delivered to the kiln for drying. Since no person can manage all this data alone, machines are needed as they manage the data side better and faster.
As far as drying kilns are concerned, data harvesting and utilisation takes place at every stage. When the kiln load arrives, it contains a lot of information about the kind of load it is. The load provides product information, species of wood, load number, the individual ID number of the kiln cart and the load volume in cubic metres.
The product information provides data about the thickness, length and width of individual boards and planks as well as the part of the tree and initial moisture content, all of which is important basic information when considering the drying settings.
Towards optimal drying
The kiln load contains a huge amount of data, but what is it all needed for? If you want a brief answer, it’s target moisture content. The load of timber to be dried can be used for many different purposes, where it’s important to get the right target moisture content. To achieve this, the right initial data is very important.
“Our new innovation is to use the weight of the kiln load to determine the right initial moisture content to make drying even more predictable and thus more optimised.”
Initial moisture content is estimated based on weight, volume and density, after which a drying formula can be determined to reach target moisture content. For example, a shipping dry wood load requires a different moisture content than sawn goods supplied straight to the furniture industry.
Our new innovation is to use the weight of the kiln load to determine the right initial moisture content to make drying even more predictable and thus more optimised.
Besides the target moisture content, it’s important that the quality of the sawn goods remains good in the drying process. Over drying wood causes shape and colour defects and splits in the sawn goods. Data and data transmission play a key role in achieving the right target moisture content and good kilning quality.
Warehouse management system knows where the loads are
Where are the loads moving or warehoused? The warehouse management system takes care of this data. Drying loads can have many potential locations. They can be going to drying, being dried, just been removed from drying, moisture balancing or warehoused. The warehouse management system tracks these loads and updates them in real time. The sawmill manufacturing execution system uses this data to operate in an optimal way.
All the various automation systems are in the sawmill’s common data network and constantly communicate with each other. Back in the day, there was someone with a squared paper notebook in the drying kiln area. The power of data is enormous in this regard.
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