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VOLUME 49, ISSUE 3/2008

Generalised linear models to analyse counted wood properties

Language: German
Pages: 5 - 9
Authors: Alexander Petutschnigg, Karl Entacher, Hermann Katz

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Linear models (e. g. linear regression or analysis of variance) are commonly used to characterise wood properties and the relations between them. For certain properties, these models are not suitable to describe relations sufficiently. Within this paper a generalised linear model (Poisson regression) and a linear regression model are applied for the number of resin pockets on boards depending on the number of resin pockets on logs. It is shown that a generalised linear model is more appropriate and reliable to describe the data.

Importance of cutting processes for the wood material technology Part 2: High-strength wood based materials from uniform wood parts

Language: German
Pages: 10 - 13
Authors: Volker Thole

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In the first part of the report the reduction process of the wood based panel industry it is distinguished with regard to the processing chain and reduction conditions. During the indirect two-phase reduction of the wooden raw material and defined cutting conditions the function-structured Elements (FSE) can be manufactured with very uniformly continuous dimensions. If, as described in the actual trial, the structured elements are obtained through cutting of boards, significantly equal structured elements regarding dimension are resulting, comparable with veneer strips. Therefore wood based panels from these structured elements are more similar to the veneer plywood than to the OSB regarding structure and strength.

Fabrication and properties of large-sized panels made of compressed spruce and fir wood Part 2: Physical properties

Language: German
Pages: 14 - 19
Authors: Frédéric J. Beaud, Peter Niemz, Hermann Blumer, Hans-Peter Wüthrich, Simon Wüthrich

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Sorption, swelling (in liquid water and steam atmosphere), thermal conductivity

and shrinkage after immersion in water were tested. The sorption behaviour of the

compressed wood is reduced in the upper part of the sorption isotherms. Compressed

wood swells more in steam atmosphere than in liquid water. Through compression the coefficient of thermal conductivity and diffusion resistance becomes clearly higher.

Coating of thermo smoothed surfaces Part 1: Liquid coating

Language: German
Pages: 20 - 25
Authors: Ingrid Fuchs

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The processing of painted elements of medium density fibreboard (MDF) demands a very high effort. Thermo smoothing is a possibility to reduce this effort. From this follows that the painted thermo smoothed surfaces have to have the same characteristics as the sanded and painted surfaces. Adhesiveness and stability by wet and hot climate are very important. In a large test program thermo smoothed surfaces of MDF were painted with water lacquers and solved lacquers. This surfaces were optical and haptical estimated. The adhesiveness and the behaviour of the samples

in wet and hot climate were tested.

Temperature history of the hot melt glue for sheathing Comparison of approximated calculations and online measurements

Language: German
Pages: 26 - 30
Authors: Sebastian Horstmann, Adrian Riegel

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Hot melts hardening by cooling and form an adequate adhesion to bonded parts only within a special range of temperature. Due to this fact, temperatures and temperature profiles have a deep impact during processing. Experiments of application of hot melts were conducted within a research project of the University of Applied Science Lippe and Hçxter and Institut fbr Werkzeugmaschinen und Fertigungstechnik (IWF) of Technische

UniversitUt Braunschweig. Temperatures were recorded online at different positions

during experiments at a profile wrapping machine. The empiric, determined data are compared with analytical calculations and hence, a model of the temperature distribution is introduced. A good correlation of analytics and empiricism is detected. Throughout processing the empiric, analytical process model should be applicable to predict process conditions and finally prevent ultimate states.

Influence of wood content and matrix polymers on the properties of wood-melamine resin-composites

Language: German
Pages: 31 - 37
Authors: Michael Roth, Uwe Müller, Andreas Endesfelder

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Wood composites are well known materials with a broad range of applications. Extruded or injection moulded wood polymer composites based on melamine resins are a new development which makes new challenging applications possible. In this work, we have evaluated the influences of wood content and matrix polymer type on the properties of these composites. The results show that the wood content determines the properties of the composites, while the resin type has almost no influence. In comparison to wood polypropylene composites have the wood melamine resin composites better mechanical properties at a higher level of wood content. The simulation of the composite properties shows that the higher shear strength of the wood resin interface determines the properties of the composites.

Standardised load carrier for the furniture industry

Language: German
Pages: 38 - 42
Authors: Karl-Heinz Wehking, André Siepenkort

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The Institute of Material Handling and Logistics /University of Stuttgart has researched into a project to increase the material flow efficiency in the furniture industry. The institute co-operated with companies and a forwarder from this sector. Initial situation was a former project in which weak spots were identified in the handling of materials along the supply chain in the furniture industry. As an implementation approach a universal load carrier which is compatible to existing transportation, storing and conveyor systems was developed and designed. The load carrier requirements were

systematically identified and entered the construction. The suitability of the load carrier was examined in practice tests.

Wear resistant coatings for wood surfaces based on UV nano-composite systems Part 2: Abrasion resistant nano-composite coatings with corundum

Language: German
Pages: 43 - 48
Authors: Helmut Bauch, Rico Emmler, Reiner Mehnert, Roman Flyunt

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In a common research project of Institut fbr Holztechnologie Dresden (IHD) and Leibnitz-Institut für Oberflächenmodifizierung Leipzig (IOM) 100%-UV-cured wood coatings, which are modified with hard SiO2-Nanoparticles and optional with micro scalic corundum particles, were developed. Part 1 of the publication (holztechnologie 49 (2008) 2) includes the setting up and the performance of nano-composite coatings, which are leading to a considerable improvement of abrasion and micro scratch resistance. To meet higher requirements for abrasion resistance a technology for incorporation of micro scalic corundum into nano-composite coatings was developed and the optimal layer composition was determined. The developed coatings are variable in a wide range of hardness and elasticity for adaptation on the specific swelling/shrinkage behaviour of different substrate materials. It is possible to create deep matt surfaces by physical matting with 172 nm-Eximer-Irradiation.

Cleaning of MDF-surfaces before powder-coating

Language: German
Pages: 49 - 50
Authors: Wolfgang Schubert

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Based on the knowledge and experience concerning the cleaning technology of surfaces especially at the plastic-industry, you will get a solution for the pre-treatment of surfaces of MDF-plates in the wood-industry. For this cleaning process it is possible to use a tool which is set up by an active electrostatic discharging system and adjustable rotating nozzles. The requirements for the compressed air and the

exhaustion of the dust particles have to be customized to the needs of the special production system.

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