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In demand for circular sawing [Holzkurier 15/2005]
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In demand for circular sawing [Holzkurier 15/2005]
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The two managing directors Stefan and Hannes Theurl (from left)
PHOTOS: KANZIAN, GRAPHICS: LINCK
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Circular sawn products and the concept of Linck, Oberkirch/Germany convinced us of investing in a profiling line", report the two managing directors Stefan and Hannes Theurl of sawmill Theurl in Assling/Austria.
Optimised twice. “Theurl decided on profiling technology with integrated optimising components for recut. A new recutting concept was realised for the first time combining two optimising systems – diagonal cant alignment in combination with flexible sideboard optimisation which was allowed by new developments in the measuring and servo technology. Exact measuring results from a 3D-scanner and short reaction times of the aligning- and positioning systems in connection with a software programme mark out this kind of optimisation”, explains sales engineer Walter Pertschy. By processing large diameter logs available in our area, we have operated a pure bandsaw line for a long time. However, the demand for circular sawn lumber has constantly increased”, says Stefan Theurl.
Switch on and produce. “Linck is a company with outstanding reputation. Project and preparation work, assembly and after-sales-service was very professional. Start-up of the plant was scheduled for August 23, 2004. The same day we switched on the line and it worked without any troubles”, Hannes Theurl is pleased being responsible for the technology and the round log purchase. Especially the electronic system convinces the managing directors.
Update of the whole plant. In the course of the modification, even the log feeding system and the Springer lumber sorting system at the sawline outfeed were updated for the increased number of logs to be processed. Besides the improved lumber quality and the simpler technical production flow in the sawline, this investment was also made in view of the higher annual production. The annual processing of logs will be increased from presently 140.000 m³ round logs to 220.000 m³. We don’t need to worry about the additionally required logs, the provision is good. “We process fine-grained round logs which is purchased in a 100 km radius”, describes Hannes Theurl.
Optimised centre- and sideboards. “The recovery of centre products increased by up to 10 % and we achieve 100 % square edged products”, Stefan Theurl is pleased. Logs with small end diameters from 12 to 50 cm are being processed. Larger diameter logs are handled by the Band Headrig. Log feeding system is designed for up to 20 logs per minute. Feed speed is 40-110 m/min. Logs are processed small end first. A 3D-scanner supplied by Microtec, Brixen/Italy and Linz/Austria is measuring the logs.
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The operator is overlooking the profiling line on 13 screens.
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The cross conveyor also acts as storage for two-sided cants prior to being recut.
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Symmetrical or asymmetrical cant alignment
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Double arbor circular saw with 325 mm maximum cutting depth
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Increased recovery. The Linck recut chipper canter produces waney four-sided cants being conform to the cutting pattern. Those cants are then sawn in the following profiler-saw unit-machine group. “The increased recovery can be achieved by the optimum cant position and the sideboard optimisation in front of the recut machine group which is particular for this production line”, outlines Pertschy. In front of recut chipper canter VM 30, the two-sided cants are measured during longitudinal pass, oriented into the correct position in the infeed system and then fed into the machine. The 3D-scanning system collects the contours of the cant surface as well as the relative position of the centre products towards the cant and controls the optimum cant position in the chipper canter infeed by the evaluation electronics. Alternatively to the split taper centering, even misshapen cants are asymmetrically or diagonally aligned to the machine centre line by the optimising programme to result in an advantage in volume or smaller wane at centre products and sideboards. The cutter heads can be automatically set to the calculated cutting position from log to log within the predetermined log gap.
Flexible profiler units. Alternatively to the fixed profiler head setting for constant sideboard width and position, the sideboard optimisation system offers the possibility to vary the profiler head position from log to log according to the optimising criteria. A second 3D-scanner collects the surface contour on both sides of the waney cant and redetermines position and width of the sideboards by means of the optimising programme. The profilers are also repositioned from cant to cant according to board position and usable width. The following double arbor circular saw with 325 mm cutting depth splits the profiled cant into centre products and sideboards.
Decisive advantages
This processing method distinguishes itself by several decisive advantages:
• Recovery increase with regards to centre products and sideboards
• Optimisation according to maximum volume or maximum value
• Smaller diameter ranges
• Small quantity of waney centre products and sideboards
• Fast and precise tool positioning
• Variable cutting pattern configuration
“This optimising system determines the most suitable cutting position for each log with regards to volume and value”, describes Pertschy.
View of the whole plant. The operator can monitor the whole line by means of 13 video cameras and four screens. “How can we use a fast line if we have problems with the removal of the by-products”, the managing directors asked themselves and so decided to replace the removal system as well. 6 Million Euro were invested in the new system supplied by Rudnick & Enners, Alpenrod/Germany including all modifications.
New further processing envisaged. The connected planer mill can now be supplied with an increased quantity of own lumber. Since May the combined heat and power system has started full operation which also allowed to further increase the added value on site. There is enough heat available for the eleven Mühlböck drying kilns. A further processing of the lumber produced is envisaged as a next step – in which direction, the two managing directors have not decided yet.
Good sales, however bad payment morale. “To date, the year 2005 is characterized by bad payment morale, however unexpected sales”, reports Stefan Theurl who is responsible for sale. “The round log supply is good. Even the pricing pressure with regards to sideboards has improved. A significant easing of tension compared with autumn last year can be noticed”, analyses Stefan Theurl.
Equal opportunities for big- and medium size mills. “A medium size mill has the same chances as a big one”, the two managing directors agree. Theurl relies on a large lumber stock to meet the requirements of the many small customers in Italy. “The customers call today and want to have the lumber supplied tomorrow”, describes Stefan Theurl the prevailing Italian mentality.
JK
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Different sideboard width by sideboard optimisation
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Visualisation of the line: Illustration of the optimum cant alignment regarding recovery according to cutting pattern
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Two-sided cant enters the recut chipper canter VM 30.
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