In an investment totalling €38.5m, GELO Timber began the installation of a small diameter sawmill back in December 2019 at its 11ha site (seven of which are currently in use) at Wunsiedel in Germany. Despite all the adversities the Covid-19 pandemic presented, it proved possible to adhere to an already tight schedule and the first log was fed through the new line exactly a year later.

The main product, lamellas for glulam timber, is primarily intended for the supply of glulam plants. Meanwhile, side boards that cannot be processed are supplied to packaging customers.

“In future, the sawmill will reduce purchasing considerably for its sites in Wunsiedel and Weissenstadt. However, 100% self-sufficiency is not possible,” explained Wolf-Christian Küspert, managing director.

Wunsiedel primarily proved attractive as a location because GELO Timber had WUN Bioenergie, a pellet producer and cogeneration plant operator as a neighbour. But WUN Bioenergie is not just any neighbour: Mr Küspert is co-founder of the energy park and, additionally, a shareholder and managing director.

This creates attractive synergies with, in essence, sawmill waste being exchanged for electricity and heat, leading to Mr Küspert calling the sawmill the “Smart solution 4.0”.

The use of an electrically operated portal crane in the log yard contributes further to the smart solution concept. The trunks are handled and stacked in an eco-friendly manner in a very narrow space.

EFFICIENT USE OF RESOURCES

The main criteria for the sawmill were the economic efficiency of the production, with few staff and a maximum of technological possibilities, along with a high production speed and short set-up times.

The Wunsiedel sawmill cuts small diameters of 80-250mm and lengths of 2.5 to 5.3m and has been designed for an annual output of 350,000m3 in two shifts.

“That may not seem a lot at first glance, but more than 18 million linear metres of logs need to pass through the plant every year to achieve this output,” said Mr Küspert. “Our sawmill in Weissenstadt, where we process larger diameters, is only handling four million linear metres for an output of 250,000m3/per year.”

FULLY AUTOMATED

Main and side boards are conveyed via a tilt destacker onto two separate decks towards the sorting and stacking system from Kallfass in Klosterreichenbach in Germany and fed through an unscrambler onto a curved conveyor. An operator visually assesses the timbers, decides whether a face section is necessary and pulls the board up to 0.5m from the conveyor. The cross conveyor is equipped with rollers that make handling of heavy boards extremely easy.

Afterwards the boards are conveyed transversely towards the wane scanner and trimmer via a TongLoader. The TongLoader grips each piece in a manner similar to a hand, separates the board film, singulating and feeding it into the next conveyor with up to 120 cycles per minute. The wane scanner determines the dimension, detects the wane and passes that information on to the sorting control system, which assigns each board an appropriate box number and information for the downstream Kallfass trimmer. The latter has seven saw blades and can also be used for destructive cuts.

The operator can also indicate additional characteristics for boards through colour marking, indicating conditions such as beetle damage, blue stain or rot.

When it came to the sorting system with customised boxes, GELO Timber decided to pick 40 inclined boxes. The capacity of each box is 30% larger than normal and, in order to reduce stacking on the premises, the Kallfass system can stack packages with a width of up to 1.65m and a height of 2m. These dimensions together with the enlarged boxes facilitate the best possible exploitation of the Valutec progressive kiln. Full boxes are emptied downwards onto a cross conveyor and the boards are separated by a step separator.

Kallfass also installed a re-sorting system for kiln packages above the cross conveyor, with one kiln package making up to two or three shipping packages. These are separated in layers through tilt destacking. The stacking sticks fall automatically onto a conveyor belt and are collected separately.

An operator can even assess the quality of both damp and kiln-dried timber again if necessary, or reject unwanted pieces. Subsequent to this, the Kallfass mechanisation system creates the layers according to the package specification and these are conveyed through the Kallfass multiple cross-cut saw. The saw is equipped with a zero line and four variable saw aggregates. Placement forks then transfer the completed layers to the stacking system. Stacking output is up to 12 layers per minute.

The Kallfass stacking system is equipped with eight double magazines for kiln and dispatch sticks. Kiln sticks are 1.6m long, while dispatch sticks have a length of 1.2m. Strip laying is automatic. Finished packages are lowered using a paternoster lift. Damp material is conveyed from there to the Valutec continuous kiln opposite.

Shipping packages are conveyed to a Fromm strapping station, which Kallfass has retrofitted with an automated feeding system for squared timbers.

As mentioned, Kallfass also provided the automated stick feeder for kiln and dispatch sticks. The feeder was automated to cope with the volume of kiln sticks required. Stick bundles are transferred to a cross conveyor and separated. A scanner checks the dimensions and detects damage to sticks such as knotholes and splitting and unsuitable sticks can be ejected downwards through a flap.

Following scanning, the sticks are collected and bundled with 10 sticks per bundle. Dispatch sticks are provided using a manually charged belt conveyor and a robot grips the stick bundles, filling the stacker magazines with them. The major advantage of this solution is the option to position the magazines variably and still fill them automatically.

SUCCESSFUL PROJECT

Complete administration of the sawmill is handled by GELO in Weissenstadt and this enabled the company to keep personnel figures low in Wunsiedel.

“We currently have 32 personnel working in two shifts,” said Mr Küspert. “The sawmill can be operated by just 11 people during each shift. We wanted to build an absolute jewel – and we’ve succeeded in this in every respect. All the solutions involved were implemented exactly as we imagined. The new sawmill means we are well equipped to face the future.”

He added that he is particularly proud of the overall concept involving the neighbouring pellet and cogeneration plant. “It’s a location advantage that nobody can take away from you,” he said.