VOLUME 49, ISSUE 3/2008

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.

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.

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.

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.

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.

Wood composites are well known materials withabroad range of applications. Extruded or injection moulded wood polymer composites based on melamine resins areanew 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 composite.

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.

In a common research project of Institut fbr Holztechnologie Dresden (IHD) and Leibnitz-Institut fbr OberflUchenmodifizierung 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-EximerIrradiation.

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.