Sortierung Seitenware, sorting side products, chargement de produit lateral

Bis auf den letzten Millimeter ausgenutzt EN Utilised down to the last millimetre

The Swedish company Åsljunga Pallen decided to invest in a new sorting system and stacking line in order to increase the sawmill's output and level of automation at the same time. Kallfass was chosen as the supplier. The mechanisation expert used all his expertise to harmonise the customer's requirements with the available space.

Åsljunga Pallen from Örkelljunga in southern Sweden specialises in the manufacture of pallets and packaging goods. The company produces around 7500 pallets a day. The sawn timber required for this comes from their own sawmill. Around 60,000 m3 of sawn timber is produced there every year, 99% of which is processed in-house. “This makes us one of the largest pallet manufacturers in Sweden”, reports Stefan Nilsson, owner and managing director of Åsljunga Pallen. The pallets are sold to customers in Sweden and Denmark within a radius of around 300 kilometres.

Best solution offered

Sorting the side goods was the bottleneck in production. “The quality control was done manually - that was very time-consuming”, explains Oscar Elzén, Production Manager at Åsljunga Pallen. For this reason, the decision was made to invest in a new sorting and stacking line from Kallfass, Baiersbronn-Klosterreichenbach/DE. As part of these conversion measures, the company also expanded its sawing line to include a resawing machine from EWD. "This means that it is now possible to cut the entire log to size for our pallet production”, the production manager continues.

“Kallfass understood how we work and which process is best for our plant, and offered a technical solution for our requirements that we liked”, explains Nilsson, who is the third generation of his family to run the company.

Space and time - two challenges

The building in which the new sorting and stacking facility is housed dates back to 1956. This has recently been expanded somewhat. “However, we had to make do with the available space for this extensive project and utilise every millimetre”, explains Dominik Hauser, who supervised the project on behalf of Kallfass, with a grin: “During installation, there were even bets as to whether the robot would actually have enough space for its intended function without having to make any adjustments to the building. To the detriment of some sceptics, however, the robot was commissioned as planned”. He is referring to the robot that is responsible for automatically filling the moulding magazine. But more on that later.

In addition to the available space, there were other points to consider: Initially, a large part of the installation was carried out during ongoing operations. “We only had six weeks of downtime”, Elzén informs us. And the roof must not be opened during installation. “Thanks to the cooperation of everyone and the high level of flexibility on the part of Kallfass, we were also able to master this”, says Nilsson and is very satisfied with the mechanisation specialist's handling. Assembly began in March and the sorting system for the main and side products has been in operation since the beginning of August.

Niveauwechsel, level changer, changement de niveau

To make optimum use of the space, the Kallfass concept has several level changes.

“Kallfass understood our processes and offered us the best technical solution. We anticipate an increase in production of at least 20%”.

- Stefan Nilsson, Managing Director Åsljunga Pallen -

Complex mechanisation

Kallfass supplied the mechanisation with transverse take-off, rising diagonal conveyor as well as cycle-in and thickness measurement between the existing sawing line and the new EWD resawing machine. “Before the resaw, there is the option of transporting the main product to an existing stacking system via an automatic take-off device, depending on the dimensions, output, adjustment or maintenance work on the main line”, explains Hauser. In addition to a direct side product infeed, a stock edger is located under the new main product infeed to the resaw, which also feeds the boards for sorting. Each of the three feeders has its own buffer level. “The main goods are buffered on one deck and the side goods on two decks. When a floor is full, it is emptied automatically so that the sawing line does not come to a standstill”, Hauser explains. A level changer takes the boards to the top. The goods are first aligned there before the Tongloader cycles them into the carrier conveyor at a rate of up to 120 parts per minute. There is also the option to cut back at zero line.

Kallfass feeding of main products, chargement de produits principal

View of the feeding of the main product to the resaw machine.

After another level change downwards, a Microtec scanner recognises the wanes and gives each board the corresponding quality or dimension. These are then placed in one of the 15 vertical boxes. The boxes are emptied downwards onto a chain conveyor, which transports the box contents further onto a traversing chain conveyor feeding the timber to the parallel stacking system. “This solution was also due to the space available”, says Hauser. A step separator and an unscrambler transfer the boards to another cross conveyor for layer formation. The Kallfass project manager estimates their output at up to 14 layers per minute. The downstream multiple cross-cut saw from Kallfass is equipped with four saw aggregates - three of which can be positioned automatically. The layers of boards are then transported to the stacking machine, which has six magazines with automatic strip placing.

High degree of automation

The robot mentioned above fills the stick magazines. Kallfass installed an automatic feeding system for this purpose. A forklift driver places the stanchions filled with sticks onto a conveyor, from where they are fed into the system. Two different types of sticks can be fed separately via a hoisting unit. After the stanchions are emptied, the sticks are fed to the scanner via a step separator and unscrambler. The scanner checks the timber for dimensions and damage. Unsuitable sticks can be automatically ejected. This is followed by the formation of bundles, so the robot can grip several strips at once and fill the magazines. Kallfass also supplied the automatic pallet feeder for the stacking system. The number of pallets required can be determined according to the length of the timber. The empty pallets are automatically removed from the magazine and pre-positioned so that the pallet is always in the centre of the workpiece length. The layers of boards are then automatically stacked on pallets. The maximum stacking height including pallet is 1.9 m. Hauser specifies a target output of up to 90 packages per day.

Kallfass dépose de liteaux automatique, automatic stick placement

Kallfass supplied an automatic stick feeding system to ensure a high degree of automation …

Roboter für Leistenhandling, magazin filling with robots, remplissage robotisé d'un chargeur de liteaux

... and a robot for filling the magazines of the stacking system.

Thanks to the high degree of automation, Åsljunga Pallen is able to operate the entire sorting and stacking line with just two employees. “We are currently carrying out the final optimisations. Then we expect an increase in performance of at least 20 per cent”, says Nilsson.

Sortierung Seitenware, sorting side products, chargement de produit lateral

Feeding the side material to the wane scanner.

Visual control before cross-cutting

Visual assessment of the goods before the multiple cross-cut saw.

Kallfass feeding of cross-cutting saw, chargement de tronçonneuse multiple

The side material is unscrambled, cut and then stacked.

Text: Martina Nöstler, Holzkurier

Holzkurier 51/52


Alles aus einer Hand EN Everything from a single source

Kallfass, located in Baiersbronn/Germany, is well known as a mechanisation specialist. The same applies to the fact that the mechanical engineering company equips cross laminated timber systems. With this in mind, we can refer to some well-known projects. Recently Kallfass has added a CLT press (Cross Laminated Timber) and a CLT turning device.

The mechanical engineering company Kallfass from the Black Forest has already been involved as a supplier in several cross laminated timber projects in Austria and Germany. The most recent work completed was that of Stora Enso in Gruvön/Sweden. Construction work on this site began in 2018 and the system has been running in automatic mode since the beginning of 2019.

To date, this is the largest project for Kallfass in the area of cross laminated timber applications. The company not only supplied the entire mechanical equipment—from the feeding of packages to the acceptance of the finished pressed elements—but was also responsible for the overall layout and the complete safety control system. The fact that Stora Enso has selected Kallfass as its supplier is probably also due to the fact that Kallfass has already been involved in the Austrian CLT plants in Ybbs and Bad St. Leonhard, Austria. The total capacity in Sweden totals 100,000 m3/year.

Large packages also possible

Stora Enso also operates a sawmill in Gruvön, Sweden which supplies the raw materials for the laminated timber elements. The sawn timber (dried and battened or pre-planed) is transported by truck to the Kallfass feeding station. This feeding station is also designed for large packages up to 5.8 m long, 2 m wide, and 3 m high. A vacuum-operated de-stacking device separates the packets layer-by-layer. If stacking strips are available, a brush automatically scrapes them off and collects them. The Kallfass mechanism separates the layers and feeds the boards piece by piece to Finscan's quality scanner. In this area, the strength and the moisture of the timber is also measured. Any unsuitable workpieces are ejected from the process.

Two paths for the boards

“The scanner provides us with the information whether there are cracks on the front sides or knots in the base of the finger joints. If this is the case, we trim the front sides," says Kallfass Managing Director Hans Haist. The boards pass through a front end cross-cut with adjustable servo stop. Subsequently, the zero line is changed and the same process takes place on the other side of the board. If the scanner also finds undesirable wood features in the centre of the board, these pieces are ejected to an upper level where a cross-cut system made by PAUL Maschinenfabrik GmbH cuts out these areas. “However, this concerns only about 5% of the total quantity. Most of it goes straight on to the Grecon finger-jointing system”, describes Kallfass Project Manager Helge Widmann.

The Kallfass mechanisation cycles both the long workpieces and the cross-cut lengths from 800 mm upwards at a rate of up to 50 boards per minute. They travel in the direction of the finger-jointing system with the continuous press. Subsequently, the mechanisation takes over the finger-jointed lamellas again downstream of the moving cross-cut saw. These lamellas are between 8 and 16 m long. The applied adhesive can now cure on a 25 m long buffer section before Kallfass feeds the lamellas into the Rex planing machine. After the lamellas are pre-planed, they are cycled in the direction of the board press: First, a system provided by OEST Mineralölwerk GmbH, applies a layer of adhesive to the the lamellas. Subsequently, these lamellas are fed into the glueing press made by DIMTER GmbH. The single-layer boards produced in this way are then taken over again by a Kallfass system.

This is where the paths split: A VOITH crane picks up the longitudinal layers and transfers them to the intermediate storage. Previously, a chop saw, installed downstream of the glueing press, has already cut the longitudinal layers to the width required by the order. In order to make the best possible use of the DIMTER press, the longitudinal layers are always produced in 16 m lengths wherever possible. If shorter boards are required, Kallfass has developed a special system to recycle the remnants of the longitudinal layer.

Transverse layers measuring up to 1.5 m are stacked by Kallfass to a height of 2 m and are also transported by a VOITH crane to a second storage area. These processes are fully automated. A controller determines the suitable storage location.

Vereinzelung der Pakete

Sawed with millimetre precision

Now, the longitudinal and transverse layers are combined to form a layer package. The longitudinal layer already has the right format. The transverse layers, measuring up to a maximum of 1.5 m long, come from five buffer locations and are transferred to a 16 m long conveyor. Several boards are placed one after the other on this conveyor until the required board length is reached. If the length is exceeded, a saw cuts the transverse layer accordingly. The timber offcut then becomes the beginning of the next layer. Subsequently, vacuum systems alternately lift the single-layer boards onto a conveyor belt upstream of the press until the layer package is completely assembled. “Several CTL boards can also be laid on top of each other using a dry joint”, explains Widmann.

Downstream of the MINDA CLT press, Kallfass again takes over the multiple press layer package, separates the elements by means of a push-off process, and transports the elements to the grinding machine. Downstream, they are supplied to a VOITH crane, temporarily stored or transported to one of the three Hundegger machining centres.

In the interview Widmann mentions two more figures regarding the safety concept: “At the Stora Enso factory in Gruvön, 1.2 km of fencing and 82 safety doors were installed”.

Full-service provider

However, Kallfass cannot “only” supply the mechanisation for a cross laminated timber factory. Since last year the company also has a CLT press in its product range. “We have developed this CLT press in response to numerous customer requests”, explains Haist. Thanks to it modular and stand-alone segmental design, it makes no difference whether the layer package is built up of boards or pre-glued panels. The customer also has flexibility when it comes to the design of the workpiece. The board dimensions range from 7 to 20 m long, 2.2 to 3.6 m wide, and 6 to 60 cm high. The hydraulic system forms the core of the system. It enables an almost isobaric (without pressure difference) pressing process. In addition to vertical pressure, Kallfass also equips the cycle press with cross pressure units on request. The area-dependent pressure control enables a pressure in excess of 1 N/mm2 even at maximum plate width.

Kallfass will complete its CLT product range with a further innovation in the future: “We have developed a board turning device for cross laminated timber, which can turn the elements very easily and quickly”, explains Widmann. The turning device handles CLT up to 16 m long, 3.6 m wide and 300 mm thick. It is designed for a weight of more than 10 t. “With this device, CLT can be turned over without any risks and without hurting anyone. For example, in joinery centres, one area of application is for two-sided processing", concludes Haist.

Kallfass presented its new CLT press for the first time last year at the LIGNA Expo in Hanover, Germany.

Vereinzelung der Pakete

Kallfass supplied Stora Enso with the entire mechanisation in the cross laminated timber system – the picture shows the separation of the packages in layers.

The scanner (A) detects cracks and knots, the Kallfass saws (B) cut off the front sides accordingly.

Pressen Taktpresse

Modular design: Kallfass manufactures the CLT press in segments so that it can be adapted exactly to customer requirements

Mechanisation of the longitudinal (left) and cross layers (right) before they are assembled into the layer package.

Verleimen, Verpressen, Wenden

Turn once, please: To bring the longitudinal layers to the correct side, Kallfass installed a board turning device.

Text Martina Nöstler, Pictures Kallfass, Holzkurier BSP-Special 2020