What the press says about LINCK
Profiling of short logs
Continuous guiding is a challenge
A new chipper canter was the focus of the Linck, Oberkirch/Germany presentation on the Ligna. It is part of a new profiling line for processing short logs which will be supplied to Bien Holz in September.
The chipper canter VM35 was especially developed to be used in short log lines. Linck supplies such a sawline to Bien Holz, Uelzen in autumn this year. The new sawmill is designed for processing 1,20-2,80 m long logs for the production of pallets. Linck presented the production sequence in a short log line as well as the associated machines to the trade visitors of the Ligna in Hannover from May 30-June 3. Assembly of the equipment at Bien Holz will start in September, production start is envisaged for January 2012. Production capacity in a two-shift operation is 300.000 m³ round logs/year. The profiling line allows feeding of logs large- or small end first. Logs to be processed are diameter sorted.
High dimension accuracy. The new chipper canter VM 35 with its new developed two-stepped cutter head can be equipped with two to four chipper knives each. “With 580 mm diameter this cutter head is considerably smaller than conventional ones”, informs Manfred Leopold from Linck, responsible for marketing and sales. According to Linck, the smaller cutter head offers two essential advantages: The lower mass allows higher revolutions and consequently higher feed speeds. A feed speed of up to 200 m/min. can therefore be achieved for small diameter logs. The simultaneous use of the VM35 for short logs from 1,20 m length on makes it possible to process small diameter and short logs. The cutter head – like all other Linck cutter heads – is equipped with a guide disc guaranteeing a high dimension accuracy. Instead of the support table presented on the Ligna, the VM 35 will be equipped with a centre chain allowing a reliable log transport. “The design of the VM 35 chipper canter provides for an easy access to the machine for tool change. One machine side can be moved sideways in a way that it is easily accessible for the operator.”
Additional newly developed machines for short log profiling lines are the profiler-saw unit VPS 35 and the split saw TS 35. Each of the four profiler heads in the profier-saw unit VPS is driven by a three-phase motor. The four sawblades are driven by one each three-phase, flat motor. All tool axes are servo-hydraulically adjustable. If necessary, the saws can be completely moved out of working position in vertical direction. The saw TS35 splits the four-sided cant in two half timbers. The asymmetrical feeding of the four-sided cants also allows an out of centre cut. The sawblades can be completely moved out of working position in vertical direction in case the split saw is not required for certain cutting patterns. “Processing of short logs from 1,20 m on guarantees high recovery even with very crooked logs”, describes Leopold the advantages of the Linck line. A large number of feeding- and guiding systems ensure the sawing accuracy of the lumber products.
Preferably small and fine? Linck met the requirements of the sawmill inudstry – and its customers – with a new stepped cutter head. “Thick chips for the pulp industry are suitable to only a limited extent for pellet production as drying and chopping requires high energy input”. Handling of fine chips is considerably more efficient for pellet production. Therefore Linck developed a stepped cutter head with retrofit knives. „The demand for fine chips is subject to seasonal fluctuations. We designed the retrofit knife set in a way that changing between fine and pulp chip production is possible at any time and with little effort only.” Fine chips as well can directly be burnt in wood chip heating stations.
Trust but verify. With regards to control and optimisation, Linck presented two new programme modules on the Ligna: Linck Control and Linck Optimize. Linck Control compares the log scanner data with the ones of the cant scanner. Axes positioning for centering at pre- and recut chipper canter as well as rotating angle for precut are calculated based on the data from the log scanner and required cutting pattern. The cant scanner calculates the data for sideboard optimisation. Linck Control can now compare the real cant values with the theoretical ones from the log scanner. The difference between theoretical and real surface is in a very tight tolerance zone due to the precise mechanical realisation of the control input. An increase of this difference is communicated to the operator – long before the difference is discovered by a periodic lumber measurement. Linck Optimize calculates the optimum cutting pattern from an individually prepared list. 3D-scanning data from the log scanner are used for this cutting pattern calculation. New is the fact that Linck Optimize determines the optimum cutting pattern in consideration of the production features in the sawline, such as automatic log rotation, diagonal alignment, curve sawing and sideboard optimisation. Installing this module on the log yard allows a log sorting according to cutting pattern. Used in the log feeding plant, Linck Optimize is optimum for processing unsorted logs.