Flexible Sortierlösung für KMU-Sägewerk EN Flexible sorting solution for SME sawmill

Existing space used as best as possible

The previous sorting system at the Wilhelm Wolf sawmill in Waidhaus, Germany, was performance-limiting and too labour-intensive. That is why junior manager Christian Wolf decided to invest in a new, flexible sorting system from Kallfass. In retrospect, it was the right decision for him – for several reasons, as he reports during the Holzkurier visit.

With a cutting capacity of around 25,000 cubic metres per year, the Wolf sawmill is a classic small and medium-sized enterprise (SME). The company's history dates back to 1870. Today, Christian Wolf runs the firm in cooperation with his mother, Gabriele Wolf, and represents the fifth generation of the family-run company. When using a gang saw and a small profiling system, and a downstream circular edger saw, the production of solid structural timber (KVH® for short), glued-laminated timber (GLT) lamellas, packaging squared timber, side products or raw goods from sawn timber (rough planer) is relatively easy. The classification and stacking of the diverse assortments were previously carried out using a simple length sorting system. In this case, employees subsequently stacked the sawn timber manually. “It was too labour-intensive and we find it very difficult to recruit staff. In addition, this sorting has significantly limited our performance,” explains Wolf. In order to become faster and more flexible, a new solution was needed.

Perfect handling

Wolf Jr. looked at several suppliers. Ultimately, he liked the concept of Kallfass, Baiersbronn-Klosterreichenbach, Germany, the best: “Kallfass has always built very reliable sorting systems and was able to complete the project in a very short time. I particularly liked the agility in the planning – all of our requests and ideas were implemented promptly and the new sorting system is specially adapted to the size of our sawmill,” explains Wolf. The renovation work was carried out last year, and the new Kallfass sorting and stacking system has been in operation at the Wolf sawmill since March. “The entire commissioning process went absolutely smoothly. The Kallfass technicians were excellent, as were the programmers," says Wolf, full of praise for the mechanisation specialist's handling. “We now have countless possibilities to deal with our qualities and dimensions.

”Kallfass delivered a system that was perfectly tailored to our needs.”

- Christian Wolf -

Kallfass supplied the complete sorting and stacking system, from the transfer downstream of the trimming and circular resaw. The latter is designed for lengths of 1 to 5.1 m and a maximum cross-section of 140 x 180 mm. A conveyor belt transports the squared timber or the main product and boards to two separate buffer decks, which are positioned directly underneath the boxes. “The buffers are dimensioned in such a way that an entire sawmill production output of three to four hours of, for example squared timber, will find space,” explains Kallfass project manager Matthias Link.

After separation, the goods go to the assessment station. The employee can set a back cut of up to 50 cm at the zero line by dragging. If a cross cut is to be made on the opposite side of the wood, the wood is marked with a luminescent chalk. The cross-cut is done later, immediately before stacking. There is also a turning device in the area of the assessment station so that even heavy pieces of wood can be qualified on all four sides. Any unsuitable pieces of wood can be separated into planks and squared timber and ejected into two stanchions immediately after cutting.

“Only one assortment goes directly into the stacking system at a time,” reports Wolf. After the cross-cut station, the remainder is fed upwards to the box sorting system via a level changer. After several discussions, Wolf finally decided on 30 boxes. This means that the space has been used in the best possible way. The boxes are emptied downwards onto a chain conveyor above the buffer decks. The wood then takes the same route as the unsorted goods towards the stacking system.

In order to be able to produce short lengths with millimetre precision, Kallfass installed the proven multiple cross-cut saw. The latter is equipped with four saw aggregates, three of which can be positioned automatically. In order to be able to respond to even more flexible to customer requirements, Wolf is already considering retrofitting a fifth saw aggregate. After layer creation, stacking forks transfer the lumber to the stacking system, which is equipped with four double magazines for drying and dispatch sticks. Finally, a conveyor unit supplies the sawn wood packages. While still in the planning process, Kallfass has already anticipated the possibility of conveniently retrofitting a strapping system.

In order to be able to re-sort dry packages, there is an external infeed. Here, the wood is separated layer by layer using a chain conveyor, which then transports the timber towards the assessment station. The sticks are carried via a conveyor belt into stanchions and removed.

Investment has paid off

After just a few months, Wolf can draw a positive conclusion in every respect: “Our downtime has significantly decreased as we are able to maintain a continuous production rate. The quality of the cut goods has increased immensely thanks to cross cuts and millimetre-precise production. This has already brought us new customers. We are now much more agile and can respond quickly to customer inquiries. I would build exactly the same way again,” Wolf concludes.