VOLUME 52, ISSUE 2/2011

One crucial result of the recent Swiss National Forest Inventory (NFI) from 2004 to 2006 is a hardwood volume increase of 10.4 %. The volume of softwood, in contrast, has reduced (2.4 %). However, Switzerland still used the bulk (70 %) of harvested hardwood directly for energetic purposes in 2009. Besides the decreasing percentage of stem wood and the more complicated processing involved, the main problem in Switzerland is that the value chain from the round timber to an end product is not closed. Predominantly the processing from sawn timber to semi-finished or finished goods is lacking. Therefore the energetic use was, and still is, the most comfortable and profitable solution for unused assortments. Solving the current problems requires the initiative and cooperation of forestry, wood industry and politics. The most important aspects will be the developing of marketing channels, the buildup of a processing industry, the realisation of further research projects and the providing of information for the end customer.

During ablation with laser beam, basically all wooden materials can be processed with suitable laser sources. In the course of the separating process with laser beam, machine-burn emerges on the narrow surfaces, respectively discoloration of the material surface in engraving. Since the heat-affected zone in laser ablation is relatively small, this technique is eminently suitable for pre-formatting (i. e. roughing) and can be combined with subsequent finishing by rotating milling cutters (to remove/eliminate the machineburn).

Thermo smoothing makes it possible to manufacture compressed MDF profile surfaces cheaply and to reduce post-milling roughness noticeably. The number of sanding and filling stages can be reduced or even superseded. As a result, there is growing interest in applying this technology, especially as the powder coating of wood materials is gradually gaining popularity. On the one hand, this affects both new equipment and the upgrading of existing wood-processing machinery, such as edging machines and CNC processing centres. On the other hand, it also raises the issue of using robots, with their greater efficiency, as well as of the configuration of flexible automated manufacturing cells for smoothing. Various solutions could be suitable for any given company, depending on its available technology and investment strategy. On the basis of experience to date, consideration thus needs to be given to finding various solutions that conform to differing requirements and to the corresponding characteristics of those solutions.

New polymeric additives affecting the surface conductivity of wood materials have been developed using polymerizationlike reactions on cellulose and derivatives thereof respectively. During the course of an interdisciplinary research project on post-mouldable wood materials based on duromer wood fibre composites these additives have been tested. It was found that after application of an additive into a wood composite or onto its surface, the surface resistivity is reduced to 107 Ohm. Taking advantage of this effect, it is then possible to apply powder coatings electrostatically onto the surface of the wood material. Of particular advantage when compared to low-molecular additives already in use, proved to be the polymer-like linking and matrix compatibility of the new additives. Besides of the antistatic finishing, these features lead to suppression of interfering migration processes, resulting in a long-lasting finishing as well as improved materials properties.

In the process of powder coating residues of the powder are accrued. Residues of thermosetting powder cannot be reused and their disposal is very expensive. Thus producers and processors are interested in the utilization of said residues. The IHD Dresden carried out work on substitution of conventional adhesives by powder coating residues for the production of HDF. High-density fibreboards (HDF) with a density of 800 kg/m³ and a thickness of 8 mm were produced using powder residues as an adhesive substitute in the present work. The results show that substitution of synthetic resins using powder coating residues for the production of HDF is possible. The requirements of DIN EN 622-5 can be met. With the use of powder coating residues as a substitute for adhesives in the HDF-production, the amount of adhesive can be reduced by 10 % to 20 %. Thus a reduction in adhesive cost is possible.

Due to their advantageous properties and the comparatively low price the paper honeycomb core is a good material for producing lightweight sandwich panels for furniture and interior applications. ccording to the specific field of application, different combinations of materials, construction methods and manufacturing processes are applied for the sandwich panel production. Part 1 of this paper describes the current situation of lightweight construction in the field of furniture and interior application as well as important types of paper honeycomb cores. Panel construction methods and manufacturing processes are shown in part 2.

The trend to high gloss surfaces is still continuing. The valuation of high gloss surfaces like no other surface character results from the perceived (emotional) impression of the surface. Only perfectly produced or delivered high gloss surfaces reach the maximum valuation of the customer. Due to that an objective quality assessment during the production process of a high gloss surface is obligatory. The quality assessment in practice is carried out by visual sampling inspection, mostly without any devices or the corresponding methodology. With a methodology based on metrologically and sensory ascertainable attributes, significant improvements in quality assessment can be achieved. Today some attributes can already be metrologically detected. Furthermore to deal with other attributes there can be used sensory assessments with well instructed assessors who inspect the surfaces methodically. Therefore the use of perception improving devices is an essential element. Consequently sensory assessments are called to be objective and offer the advantage to get to look at the surface from the customer’s point of view