Three-layered composite materials consisting in wood-chips bonded by a resin (particleboard) were successfully produced from two by-products: plum and apple tree branches, waste biomass produced after orchard pruning; a third particleboard was made from an industrial softwood blend as a reference. After collecting the branches, the raw materials were characterized in matters of density, bark content and bulk density of particles. Various physical and mechanical properties were assessed in accordance with European Standards for wood-based panels, namely thickness swelling, water absorption, modulus of rupture, modulus of elasticity, internal bonding strength, screw withdrawal resistance, as well as density profile and machining properties during milling and drilling. Modulus of rupture was 14.4 ± 1.2 N mm⁻² for plum-based panels and 12.8 ± 2.3 N mm⁻² for apple-based panels, while modulus of elasticity was 2576 ± 140 N mm⁻² for plum-based panels and 2432 ± 345 N mm⁻², which fulfills the mechanical requirements for panels of furniture production and interior equipment purposes which of this kind of materials is modulus of rupture of 11 N mm⁻² and modulus of elasticity of 1600 N mm⁻². The results showed in general, a good performance of the composite materials elaborated from waste biomass, thus offering a potential revalorization of a rather undervalued by-product.

This paper presents the particle-size distribution of dust created by the drilling of selected wood composites, which was carried out using a CNC machine. The particle-size distribution was studied through two methods. Two analyses were performed: the sieve analysis of samples from the whole mass of collected dust and the laser diffraction analysis of the finest fraction isolated by sieving. The results presented general information about the particle-size distribution of the dust, as well as detailed information on the content of the finest particles. This information revealed that the particles might pose a potential risk to the health of workers employed in the woodworking industry. This potential risk is due to the possibility of their dispersion in the atmosphere surrounding the workplace and their size, which allows them to be respirable. The relationship between the fineness of the dust and the type of wood composite was also tested. Most ultrafine particles are formed during the drilling of fibreboards and are especially produced in traditional wet technology.

In this paper, we analyze the possibilities of the protection of tools for wood machining with PVD (Physical Vapor Deposition) hard coatings. The nanolayered TiN/AlTiN coating, nanocomposite TiAlSiN coatings, and single layer TiN coating were analyzed in order to use them for protection of tools for wood machining. Both nanostructured coatings were deposited in an industrial magnetron sputtering system on the cutting blades made of sintered carbide WC-Co, while TiN single layer coating was deposited by evaporation using thermionic arc. In the case of TiN/AlTiN nanolayer coatings the thickness of the individual TiN and AlTiN layer was in the 5–10 nm range, depending on the substrate vertical position. The microstructure and chemical composition of coatings were studied by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) method. Additionally, in the case of the TiN/AlTiN coating, which was characterized by the best durability characteristics, the transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) methods were applied. The coatings adhesion to the substrate was analyzed by scratch test method combined with optical microscopy. Nano-hardness and durability tests were performed with uncoated and coated blades using chipboard. The best results durability characteristics were observed for TiN/AlTiN nanolayered coating. Performance tests of knives protected with TiN and TiAlSiN hard coatings did not show significantly better results compared to uncoated ones.

Machinability issues during drilling of wood-based materials were evaluated. Three types of standard wood-based materials of substantially different internal structures, i.e., fibreboards, particle boards, and veneer boards, were selected as test samples. The experiment consisted of drilling holes through samples made of 14 different materials. The purpose of the experiment was to determine the quality of the edges of the holes and to evaluate values of the cutting force and torque. The obtained results were used to determine the relative machinability indexes based on the machining quality and cutting forces. These indexes were defined by referencing the obtained data of each tested material to one selected reference material: medium density fibreboard. The experimental data showed that the machinability index based on the quality criterion was not correlated with the index based on the cutting force criterion. The quality index was not correlated with the basic, routine parameters of wood-based boards. However, the cutting forces index sometimes showed a significant correlation of this type. The quality index showed the influence of the internal structure and homogeneity of the different types of materials.