The starting point for considering manufacture of extensive solid-wood elements in Gaishorn, Austria, in addition to a 150,000 m3/year Laminated beam structure, was the fact ”that wood construction can only gain substantial market shares by using a genuine solid construction element. An element with mass, with the advantages of wood – lasting, moisture-regulating, CO2-neutral – that is simultaneously industrially manufactured and thus permits economic construction,” emphasizes Adi Aigner, who was Managing Director until the end of June and who founded Systemholz 17 years ago with Heinz Dominici.
Special cutting for further processing
Anyone already creating 150,000 m3/year Laminated beam knows how to handle raw materials – and the owner cuts the latter in accordance with his purpose. There is a central presorting works that feeds the three Laminated beam lines and now the CL T (Cross Laminated Timber) line with raw materials. The mechanization of TC Maschinenbau has brought about handling of complete transportation in production. This contribution to the x 20 million investment represents the biggest single order in the 15-year history of this St Veit company.
Further multi-sensor check
For each Kalmar lifter, production supply feed of sawn timber uses two separate combinable mechanization processes. This pre-sorted raw material is again examined by a Golden-Eye. The Microtec multi-sensor scanner delivers information on the current cutting decision, plus information on additional quality characteristics. One concave deformation notification from ATBBlank is inserted in each instance. It recognizes the plank position at up to 240 m/min transverse throughput and if necessary initiates a ’Turn’ command. The subsequent circular cross-cut saw now cuts away unwanted wood markings, and can also turn a longitudinal position into a transverse position, i.e. short-cut wood can be made from long-cut wood.
High-performance finger-jointing
Endless finger-jointing is performed by a unit from SMB, Vöhringen/DE. ”With its 15 pieces/ min it is the most powerful one ever built,” explains Hans Lieble, SMB Maschinenbau, Vöhringen/DE. SMB and TC Maschinen have for years been linked by co-operation regarding construction of powerful laminated timber plants in Central Europe. Scheuch supplies all the state- of- the- art suction, dust-removal and pneumatic materials-handling technology.
In the production flow there follows a generous multilayer warehouse into which longitudinal and transverse layers are buffered – the top lams are stored here for ascertainment of visual quality. This ’central warehouse’ in mid-production brings MM Systemholz operational safety, as different previous and subsequent production speeds are compensated for.
Flexible process
The emphasis on making transverse layers out of originally longitudinal ones should guarantee that each lam will find its technically and optically appropriate place in the Cross laminated timber element. Yield optimisation for MM Systemholz is also important.
Exact lams essential
For MM Systemholz’ Cross laminated timber the joints are not glued. This makes four-sided planning even more important – a process performed on two Rotoles lams planers from Ledinek, Maribor/SI. They ensure creation of the usual well-gluable surfaces, and simultaneously calibrate the lams to exact dimensions and angles – four-sided up to 200 m/min.
The core of the plant is its precise stacking of the press cake from longitudinal and transverse layers and the extensive gluing and subsequent pressing of the latter. To take the short and long-cut wood from the two feeders to the preparing table, TC Maschinenbau uses special Schmalz vacuum lifters.
Internally developed gluing
At the preparing table application is then performed in two phases using the internally developed glue applicator from Casco Adhesives. The equipment was built by Casco Adhesives together with Wolfgang Gollenz, who holds commercial power of attorney and who, following the departure of Managing Director Heinz Dominici has borne sole responsibility for production since 1 July. The concept and control are thus entirely attributable to MM Systemholz. What has resulted is unique, precise glue application for varying widths (max. 3 m). Casco Adhesives emphazises that the melamine system is characterized by short pressing times and low formaldehyde values, and that the formaldehyde values in the end product are not higher than with PUR-glued elements.
HF pressing using 885 t
Three to seven layers of up to 40 mm lams produce elements up to 278 mm thick, which are pressed in the subsequent Höfer-Duo press using high frequency. The horizontal pressing force of up to 20 ton is also important in this context, ensuring sealing of the joints between the lams – even without gluing. The vertical pressing force is 885 ton. For this purpose Höfer supplied two presses weighing a total of 190 ton.
The HF generators were installed by the Swiss specialist company Plustherm of Wettingen. Using these generators, heating should be sufficient even with the maximum element thickness of 278 mm. The up to 16.5 m long element leaves the press after three pressings.
3 m wide spiral planer
Following conveyance by a large transverse conveyor the elements are then processed in a Ledinek planer. A special spiral shaft is incorporated that processes the elements up to a width of 3 m. Thus the exact end dimension is achieved, as well as a genuine finish. ”Every element is planed, but the customer decides whether there is also to be bonding on the Maka portal bridge,” explains Bernd Troppmann, who holds commercial power of attorney. The experience after five months is that nearly all orders also require further processing. Windows and doors can be molded using CNC control. There is also the possibility of any number of moldings. “Tongue & groove moldings are all possible,” according to Troppmann. ”But we don’t want to make everything. The final detailed work, e.g. provision of sockets, is to be carried out by carpenters using hand tools.”
Further possibilities
In accordance with market development, at the end of production there is also the possibility of incorporating further processing centers. Maka’s big bonding station can already be obviated for a single molding. The elements are manipulated and stacked for lorry transportation using Voith indoor cranes. Radio control can be used to stack them optimally for freight and in a manner suitable for the project.
Few staff necessary
The extensive automation of the plant and the direct linkage to work preparation – using five technicians – reduce operating and control measures to a minimum. No more than six staff per shift are necessary. TC Maschinenbau and Oesterle Maschinen are proud not only of being able to meet all Gollenz’s and Dominici’s requirements but also – and especially – of the speed achieved.
The order was placed in January 2007, delivery commenced in July, and trial operation took place in January 2008. The changeover to two-shift operation took place as early as in June 2008. ■