Process combination of peeling and sawing of large diameter roundwood: Peeled Boards for yield-optimized timber construction products


Project duration: 10/2023 - 09/2026

The current industrial cutting of roundwood, with focus on coniferous roundwood, is optimised for medium roundwood diameters (MRD < 40 cm); consequently, large diameter roundwood can only be fed into a highly industrial cutting process in specialised sawmills. However, the standing stock of large diameter timber, currently 25 % of the total stock, is considerable in Central European forests (DACH‑region ~1.273 billion cubic meters, of which 800 million cubic meters are coniferous) and is also increasing. In addition, there is an urgent demand to rejuvenate the forest stand in order to be able to guarantee an ecological balance. Taking this as an opportunity and integrating the SDGs of the United Nations with a focus on increasing the yield from roundwood, reducing the energy and material input in the production of wood construction products, and increasing their performance, it is planned to analyse the combination of the peeling and sawing processes within the framework of the planned research project "rethink_LTprocessing" and to significantly increase the thickness-range of peeled raw wood products.

In order to pursue the goals defined in this research project, the following work packages (WP) are defined: WP2 – Process Optimisation, WP3 – Classification, and WP4 – Products and Applications. In WP2, the currently known process steps for obtaining peeled (thick-)veneers are to be analysed and optimised with regard to their suitability for layer thicknesses of ≥ 5-15 mm (board thickness). The main process steps are the pre-treatment of the logs, the peeling process itself and the drying of the peeled, flat wood raw materials, which will be referred to as peeled_boards. WP3 is primarily dedicated to the characterisation and classification of single-layer peeled_boards, lamellas (pebo's) made from them and multi-layer glued peeled_boards (peeled_panels). The joining of peeled_panels and pebo's is also dealt with. Relevant material properties must be determined, influences from the peeling process also on sawn wood raw materials have to be quantified and criteria on quality and sorting have to be defined. Within the scope of WP4, homogeneous/combined one- and two-dimensional load-bearing structural timber products with optimised shape and structure, manufactured from raw wood products from the combined peeling and sawing process, are to be compared with established board- and panel-based structural timber products and the advantages and disadvantages will be presented. In addition to "pebo" board lamellas or peeled_panels as raw wood products, orthogonally glued peeled_boards can also be used. Furthermore, WP4 will analyse the potentials for one- and two-dimensional form and structure-optimised moulded profiles (Ultra High Performance Profiles, UHPP) as well as formwork systems made of peeled_boards in combination with (thick-)veneers and sawn raw wood products.

The manufacturing process of peeled raw wood products in board thickness dimension per se and in combination with a subsequent sawing or peeling process of the residual roll is considered to be largely unexplored to date. This concerns, among other things, the limits of possible peeling thicknesses depending on the log dimension and the pre-processes as well as their optimisation, the effects of any pre-processes on sawn timber products of the residual roll, the peeling process and process parameters optimised in this respect, the possibilities of industrially drying and subsequently classifying (sorting) such peeled products. The basic research project "rethink_LTprocessing" aims to create the essential foundations for dealing with these questions and to illuminate the potential of this combination process and that of the peeled and sawn raw wood products produced in the process for the production of load-bearing structural timber products. The aim is to find an optimal setting between the combined processes of peeling and sawing and to make the best possible use of the potentials of the raw wood products produced in this process in homogeneous / combined one- and two-dimensional load-bearing structural timber products with optimised structure and shape.

Funding programme BRIDGE 1

BRIDGE 1 project

The goal of the funding programme BRIDGE 1 is further development of potentials of both potentials of basic research and experimental development. The Programme contributes to deepening a research cooperation between science and economy, facilitates the access for small and medium-sized enterprises (SME) to scientific research, favours the transfer of researchers from universities to industrial research and intensifies the research achievement in the area of high-quality industrial research and experimental development.