JAHRGANG 47, AUSGABE 5/2006

High speed cutting (HSC) is an appropriate method to increase the productivity of woodworking machines by reducing the processing time and at the same time improving the cutting quality. Apart from the right machine equipment the HSC-technology requires specialized tooling solutions to work on higher speeds than conventional. Tooling systems for HSC on CNC routers in any case require accurate and rigid tool chucks as well as small tool diameters. This report is based on the investigations of the research project No. 540 „HSC-Holz sponsored by the German BMBF and gives a summary of the tooling requirements and the benefits which could be achieved through HSC.

The weathering resistance af differently banded medium density fibrebaards (MDF) was evaluated. The MDF were prepared using thermamechanical pulps (TMP) fram pine and melamine-urea-phenalfarmaldehyde (MUPF) resin, phenalfarmaldehyde (PF) resin, tanninfarmaldehyde (TF) resin, and adhesives based an palymeric 4,4'-diphenylmethandiisacyanates (PMDI) as binders. After autdaar expasure far several years the unsealed baards were tested regarding the internal band strength, bending strength and thickness swelling. The results shaw the autstanding weathering resistance af the baards after autdaar expasure far three years. Especially, the internal band strength af PF-banded MDF and the thickness swelling af TF-banded MDF were remarkable.

Turkey oak (Quercus cerris L.) is one of the most widespread wood species in Hungary. Based on its properties, this wood could be used for several indoor applications (e. g. par- quet flooring, furniture components and front panels) if its colour could be made more uniform. Turkey oak was steamed by applying heat in the 80 to 110 °C temperature range. It was found that the colour difference between sapwood and heartwood of Turkey oak could be reduced significantly by steaming at the applied temperature range. The optimum steaming time for colour homogenisation was 12 hours at 95 to 110 °C temperature range and 3 days at 80 °C.

The glue application system is one of the most important units regarding the edge processing. After heating the hot melts are applied on the board or the edge material using a special roll. This process is very intensive concerning energy and time. The melting of the glue with laser allows a direct positioned energy placement. The arranged investigations show that standard glues can be melt using laser and the adhesion of the coating material and the board can be realized under production conditions. In part 1 of this publication (holztechnologie 47 (2006) 3, S. 37-42) basics of hot melt reactivation by laser radiation are presented. The following part 2 describes the transfer of the procedure to an industrial edge banding machine. The properties of the glued joint, the economics and the potential of the procedure are discussed.

Part 1 of this work was concerned with measurements of variations in specific pressure and mat thickness during the continuous hot-pressing process of MDF and further on with the determination of their impact on the board properties (Realization at the University of Hamburg, Department of Wood Science). Part 2 contains investigations on a laboratory press for the determination of the direct influence of purposeful changes of the press regime on board properties of MDF. The level and the duration of the three sections of the press program were varied. The important physical-mechanical properties of the manufactured MDF were determined and submitted of a gross density standardisation (Realization at the IHD Dresden).

Experiments to heat up wood homogeneously were realized with adjustable/controllable microwave technology as an open system. The gained results will be shown with the help of practical examples.

3D laminated furniture fronts are stressed by manufacturing and usage in different ways. By experiments and examination a contribution was made to the mechanical stress. Without any drillings the air pressure inside the fronts could rise. Other reasons for compression are humidity and temperature expansions which can cause lamination peeling. All this forces has to be absorbed by the adhe- sive Joint. In case of a collapsing Joint it is leading to a pee- ling stress mainly in areas of surface mouldings

Since 1989, the "Tree of the Year" board of trustees has drawn attention to 18 tree species that are of importance for various fields. The overview briefly outlines the reasons for the selection by the Board of Trustees as well as some tree and wood characteristics. Part 1 presents the trees from 1989 to 1997: English oak (Quercus robur L.), European beech (Fagus sylvatica L.), large-leaved linden (Tilia platyphyllos Scop.), mountain elm (Ulmus glabra Huds.), sparrow-grass (Sorbus domestica L. ), yew (Taxus baccata L.), Norway maple (Acer platanoides L.), hornbeam (Carpinus betulus L.), rowan ash (Sorbus aucuparia L.)