From the log infeed upstream of the sawmill to the finished board made of cross-laminated timber (CLT), the material flow at the new facility of best wood SCHNEIDER GmbH in Messkirch, Germany, takes place with minimal manual interaction.
Kallfass supplied all the sorting and automation solutions, starting from the point where the saw takes over until the link to the future CLT plant.
“We were seeking partners who would join us in planning an unusual sawmill with us,” said Andreas Schilling, site manager at best wood SCHNEIDER in Messkirch. “In Kallfass we found that partner, which also has the necessary open mind to think about matters in a new and alternative way.
“In addition, we already knew Kallfass, which had successfully completed projects in our main factory in Eberhardzell, Germany. “So it was easy for us to decide to collaborate again on this major project.”
The scope of delivery of the mechanical engineering firm from the Black Forest starts at the takeover of the timber directly downstream of two sawing lines. Whilst using two log band saws and a chipper-canter line for all logs with a crown diameter of less than 30cm, SCHNEIDER will be cutting approximately 350,000 solid m3/year once the production has reached its full expansion stage. “By combining band and circular saw technology, we are particularly flexibly positioned and can act as a full buyer for the forestry sector,” said Mr Schilling. “In times when procurement situations become increasingly problematic, this is important.”
FLEXIBLE SORTING
Four buffer levels, one level directly above the other, take over the sawn timber.
“Each level is designed for the exact filling quantity of the subsequent drying package. This enables us to time the wet sorting process selectively,” explained Hans Haist, managing director at Kallfass. “The entire sorting system can process boards measuring 3,600 – 4,300mm long and 95 – 259mm wide. Thicknesses from 36 – 53mm can also be processed, ensuring the greatest possible flexibility for further processing in the company’s sorting area. In terms of efficiency, the system also meets all requirements. It operates at 80 cycles per minute in both wet and dry areas.”
During the process, the individual levels are emptied one by one. Subsequently, the boards are separated before their thickness is measured, and the Kallfass multiple circular cross-cut saw trims the excess length of the lumber as required.
The wood packages are then automatically stacked for drying purposes. best wood SCHNEIDER works with mixed widths and thicknesses. “This makes little difference for the continuous kiln, and the Kallfass systems also cope very well with it,” said Mr Schilling.
Many companies already rely on a drying chamber solution; therefore, mixed packages are nothing unusual in the timber world. What is immediately striking on a walk through the factory is the size of the individual packages of sawn timber.
“The wood packages measure 2m wide by 4m long,” said Mr Haist. “The most impressive aspect, however, is the height of these packages, each one standing 6m tall. That means, depending on the moisture content of the lumber, up to 30 tonnes are transported through the halls with each package. The demands on our automation systems were, therefore, exceptionally high.”
FULLY AUTOMATED TRANSPORT
Subsequently, the finished stacked wood packages are hydraulically lowered and automatically taken over by the dryer infeed.
“The complete material flow is 100% automated,” said Mr Schilling. “This means zero forklift operations and zero manual transport between production phases.”
A total of 150 transport trolleys are in circulation simultaneously, ensuring a constant flow of material throughout the entire production system. “The fully automatic charging of the continuous kiln on rails is something unique and certainly one of a kind, at least in central Europe,” said Mr Haist.
SORTING SYSTEM WITH BYPASS
Once the wood packages are ready and dried, Kallfass takes over again and uses a vacuum lifter to destack the packages. Next, a brush automatically sweeps and tosses the stacking sticks onto a conveyor belt. The latter moves the stacking sticks along the dry sorting unit back to the wet sorting area. Here, before the sticks are used again, they are measured and checked for their ongoing suitability using a board shape scanner.
The dried slats are then separated again, and their dimensions are measured using a laser before the wood moisture content is measured without contact in a continuous process. The downstream multi-level sorting system extends over a length of 128m, has 35 levels and – like the wet line – has a capacity of 80 cycles per minute. The uppermost level is about 20m above the factory floor.
“Our unsorted cutting method places increased demands on the sorting process, which Kallfass addressed and was also able to comply with,” said Mr Schilling.
An absolutely unique Kallfass feature is the integrated bypass system, which connects the dry with the wet sorting line. If a slat does not pass the moisture test, it is immediately fed back to the wet sorting line and thus reintroduced into the process.
CONNECTION TO CLT PLANT
The Microtec Optiside cup scanner detects each dried and sorted slat leaving the sorting system. Subsequently, the Kallfass planing machine infeed is accelerated by up to 250m/ min. Downstream of the pre-planing machine, a Microtec Goldeneye scanner optimises each slat for subsequent cross-cut processing.
Finally, the slats are packaged again using a cross-stack method and transported directly to the future CLT plant, or strapped and temporarily stored using a hoisting unit to load the lorry.
