Optimising Log Rotation – Adding Tens of Millions of Euros in Value to Sawmilling

The competitiveness and profitability of the sawmill industry depend largely on the efficiency of the production process and the optimal use of raw materials. A significant but often underestimated factor is the accuracy of log rotation. The standard deviationof rotation at sawmills may still be as high as over 20 percent, even though it could be brought down to as low as 3 percent with modern equipment.

According to research (SP Technical Research Institute of Sweden), accurate log rotation has a truly significanteconomic effect. The yield difference between the best and worst rotation maybe as high as 5-6%.

Log Surface Texture Analysis

In 2008, Lisker began to think about how more accurate rotation control could minimise rotation errors and greatly reduce the standard deviation. In partnership with texture analysis specialist,Doctor of Science (Technology) Topi Mäenpää, they wondered if it would bepossible to keep track of log rotation in real time using nothing but thesurface, and without making any new markings. In 2010, this resulted in thebeginning of the development of Profi-TC.

Kaarlo Kerkkänen, co-founder and CEO of Lisker Oy, says that making use of texture analysis has been the foundation of the top performance and success of Profi-TC.

“Artificial intelligence is now an essential component of many technologies, and the texture analysis library also makes use of advanced self-organising maps (SOM) developed by Teuvo Kohonen as early as in 1982. These self-organising maps developed by Kohonen are a basic method of neural network models, and they make it possible to classify and visualise large amounts of data with great efficiency. This makes them especially useful in the optimisation of the sawing process as well.”

Profi-TC – Precise Rotation with No Moving Parts

Log rotation has traditionally been adjusted manually or using simple systems that were unable to monitor log movements in real time. Lisker’s modern optical measurement systems such as Profi-TC utilise machine vision and texture analysis to observe log surfaces. Automation eliminates all systematic rotation errors and improves accuracy.

A special feature of Profi-TC is thatit keeps track of the rotation without needing any markings, lasers, or other technical solutions. This reduces the number of moving parts and minimises the need for maintenance, which makes the system a very dependable and long-lasting component of the saw line. Profi-TC can be installed on existing saw lines, and a suitable place for it is almost always found.

The latest Lisker systems achieve a standard error of zero, and the standard deviation has been brought down to less than 5 degrees, at best to only 3 degrees. This makes it possible for sawmills to ensure that all logs are sawn in the optimal position.

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Yield Improvements and Economic Impacts at Sawmills

The sawmill industry is continuously moving towards more intelligent real-time solutions that improve the efficiency and profitability of the production process.

Accurate rotation is already generating direct economic benefits. According to Kerkkänen, sawmills that have adopted optimised rotation technology are already seeing yield improvements as high as 3%. This means a payback period of only a few months for the investment at large sawmills.

And if this improvement is scaled to the entire industry, the results are impressive:

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