VOLUME 48, ISSUE 1/2007

The quality of prediction of a timber bending beams property has to be increasing if additional information becomes available. The paper discusses the fundamentals of updating and there applicability to timber bending beams. This will be done by tree examples, taking into account tree different types of additional information. Based in this tree examples some application limits and effects to safety analysis and research questions are mentioned.

The series of papers, which is beginning with this article, shows new potentialities for the automation and assurance of efficiency in the machining of shaped wooden parts. These new potentialities are based on the hexapod of simple design. Starting from changed requirements and constraints the relevant spectrum of parts is characterized at first including the requirements to process and motion of the wood machining. After this the hexapod is specified as a flexible and low cost motion system for the economical machining of shaped wooden parts. In the following 3 papers the adaption and configurations of the machining system are presented in details as a economical solution for the machining of the foregoing defined categories of part. Thereby relevant problems of automation are discussed.

Tensile and compressive strength, their corresponding elastic modules, bending strength, Poisson's ratio and fracture toughness KIc were defined in the plane on industrially produced particle boards, MDF and OSB. Additionally breaking elongation and tensile energy absorption were determined. The highest value for breaking elongation and tensile energy absorption were reached for MDF. The fracture toughness KIc behaved analogue to the tensile energy absorption. For the particle boards and OSB, compressive strenght was bigger than tensile strength for loadings in the plane; MDF showed no consistent tendency. For all the materials, bending strength was bigger than tensile and compressive strength. Poisson's ratio for tensile and compressive loading for the lateral contraction was determined in and perpendicular to the plane.

Derived timber products such as MDF are efficiently made and a widely used material of woodworking industry. A wide variety of such timber products is made from MDF. Different climate conditions during the use of these products may induce irreversible deformations. The Knowledge of the material behaviour is important for the quality and that is why the furniture industry demands for a simulation model to predict the deformation behaviour in the case of different climate exposures. It is presented a finite-element-based simulation model for MDF at different climate conditions. Its special feature is the solution of a multi-field-Problem (thermodynamics, mechanics) on a similar discretisation level.

The true temperature at the edge of a woodworking tool can not be measured, therefore its value may be underestimated. Theroretical and experimental investigations were performed to establish the effect of cutting speed, chip thickness, tooth angle and edge wear on heat intensity and temperature distribution within the cutting tool. Finite element analysis of the temperature distribution showed that the edge surface may reach high average temperatures (400 to 600 K). In addition, due to a high amplitude cyclic temperature fluctuation, high Peak temperatures (more than 1000 °C) may develop near the edge for a very short time. Softening may occur in a less than 0,1 mm thick layer near the edge, and the duration of temperatures exceeding the softening Limit (around 600 °C) is 5 to 8 · 10^-4 within each revolution.

In the practical use of flooring surfaces more and more fine scratches are the reason for claims. For some environmentally friendly water based systems also irreversible traces of black rubber shoes cause problems. For a better differentiation of flooring surfaces a multiple scratch test method using a Mini-Martindale-Tester with Scotch Brite fleeces as scrub material was developed in a research project. The results of this method are in good correalation with the results of field tests on parquet surfaces. Current results on different overlay types of laminate floor coverings will be demonstrated. Furthermore an other test device for the determination of black shoe mar resistance using different rubber types decelerated abruptly was developed to differentiate parquet lacquers.

The appliance of Simulation (DES: Discrete Event Simulation) in the woodworking industry can not be seen very often. The cause for this fact is mostly the insufficient knowledge about the application range of simulation. The use of the simulation is not a cure-all but the achievements in cost and time savings are immense and positive effects by the support of the wholistic planning can be expected.

The publication contains research results on the use of fibre from wheat straw in the production of MDF. The tests confirmed the very good suitability of PMDI for the production of pure straw fibre boards. By using UF resin and MUF resin, the requirements for the board types MDF and MDF.LA according to DIN EN 622-5 could be met with a proportional substitution (up to 25 %) of wood fibre by straw fibre. As a result of the investigations and under the current framework conditions, the main possible application of straw in the standard wood-based materials sector is likely to be primarily as a partial substitute using conventional low-cost resin systems. From a process engineering point of view, it makes sense to mix the straw chippings into the wood chips before defibration and then to defiber both raw material components together.