Edger with integrated value optimization

The Swedish Catech edgers date back to the 1970s – a time when the first automated edgers were developed. Since then, Catech has been one of the leading brands in the area of high-speed edge-trimming, and USNR has already successfully installed more than 600 systems under the established brand name, as the company informs.

Furthermore, Catech did important pioneering work in the area of unmanned plant operation – in contrast to many of its competitors, whose machines mostly cannot do without an operator to this day.

Nowadays, edgers are sophisticated high-precision machines. At USNR, the geometric scanning and optimization units perfectly match the rest of the system mechanics, such as the feed and edge-trimming units. In other words: Catech machines work at the technically possible limit in terms of speed and yield. While edgers from European manufacturers often still rely on the purely geometric detection of the outlines of logs and, as a result, on quantity-oriented yield, USNR’s North American customers have been using Vision Scanning (automatic image processing) and value optimization since 2009, i.e. when the first system was installed in the US.

A merging of technologies

Merging two technologies into one seemed like the next logical step for USNR. No sooner said than done: Catech XT edgers are now equipped with a two-sided image capture system including value optimization. Other manufacturers have tried to combine the two before. However, the Catech XT is the first solution on the market which is able to generate a two-sided color scan.

Combined with powerful optimization systems, USNR’s BioLuma 2900 LV sensors guarantee the reliable detection of a wide range of wood defects. On the short distance between the scanner and the saw infeed, the system makes a lightning-fast decision based on the maximum value optimization of the products. High-performance computing systems make sure that the optimization process does not slow down the entire process. The maximum capacity of the Catech edger is 75 cycles per minute. The resolution of USNR’s BioLuma 2900 LV laser sensors is 8 mm, while that of the color cameras is even 0.5 mm. Thanks to the steady increase in resolution, accuracy and yield can also be improved continuously. In addition, higher computing power ensures that even complex calculations can be made in very little time.

Value and yield optimization

Value optimization works at both ends of the quality spectrum. Wood which would not meet the criteria for high-quality products can be optimized with regard to its maximum possible width. This way, as much wane can remain on the pieces as the sorting criteria allow. Conversely, a board which has defects on both sides but still has enough defect-free potential can be ripped into more narrow products which then have a higher overall value than their wider alternative.

The first customer in Europe

Norwegian sawmill company Moelven of Mjøsbruket was the first customer in Europe to order a USNR Catech edger with both optical and value optimization. Moelven is Norway’s largest timber company and operates production sites in Norway and neighboring Sweden. Before the new machine was installed, the company had been using an edger from Söderhamn Eriksson (now part of USNR) for 20 years. Recently, however, the old model was no longer able to meet the high requirements for yield and quality. For example, one requirement for the new machine was to increase the number of cycles by 20 per minute.

When Moelven made the decision to invest in an upgrade, USNR was about to launch the new technology and was looking for a customer who was willing to test it over a period of six months. USNR found that customer in Moelven and after six months of intensive testing, Moelven’s management was certain that they wanted to use USNR’s newly developed technology in the future.

Not only suitable for pine logs

80% of the lumber produced in Mjøsbruket is exported. The poorer qualities with a higher proportion of wane are sold on the domestic market, while sharp-edged products are reserved for the international lumber market. What may come as a surprise is that Mjøsbruket is a sawmill which cuts spruce logs, not pine logs.

A common misconception is that value optimization only makes sense for companies which process pine wood since the differences between products of higher and lower value are bigger in pine products. Mjøsbruket, however, proves that that does not have to be the case. The wood is sorted according to well-known Nordic criteria, to which USNR’s scanning systems have been adapted. Although different criteria apply on the edger and in dry sorting, the results work together perfectly.

Successful project

Sturla Vestrum, Mill Manager at Moelven Mjøsbruket, is satisfied with the investment. The entire project went according to plan and was completed successfully. The accuracy of the edger and the sorting machine have improved significantly. The line is currently running at a constant speed of around 60 cycles per minute, which corresponds exactly to the factory specifications.

Moelven has never before had so few boards of the sixth quality class, which is the lowest. In terms of the value of the individual products, this also led to a substantial increase in total output. With the machines being much more precise now, Moelven can run its production in a targeted way and focus on different quality spectrums, depending on demand. “We have fundamentally changed our attitude towards sideboards. It’s no longer about quantity alone. The products also have a higher value now,” Production Manager Terje Eng comments.

A convincing solution

Moelven did not remain the only USNR reference customer on European soil for long. “In the past few months, a number of other customers have opted for our value-optimizing edgers,” Eckart Müller, USNR Sales Manager in the DACH region, tells us. Customers include Slovenian sawmill MBS List, which also ordered a Catech XT 2900 LV from USNR. “We will deliver this system already in September,” Eckart explains and adds: “The same system will be put into operation in a Baltic State in the coming weeks, and Holzwerke van Roje, too, will be using a value-optimizing extension in addition to the geometric scanner in the future.”