Filters
The influence of feed rate during pilot hole drilling on screw withdrawal resistance in particleboard
AbstractScrew withdrawal resistance (SWR) is a metric that assesses the strength of furniture joints made with wood screws. The SWR value is influenced by several factors, such as the size of the screw, the depth to which it is embedded, the diameter of the pilot hole, and the material properties of the furniture components that are being joined together. These factors have been widely studied in the scientific literature. The objective of the research was to investigate the previously unexplored factor of a feed rate during pilot hole drilling and its influence on SWR. This study used three particleboards composed of raw pine material and urea–formaldehyde resins; the boards varied in average density (633, 637, and 714 kg/m3). Blind pilot holes with a diameter of 5 mm and depth of 25 mm were drilled in these boards using three significantly different feed rates (0.033, 0.33, and 3.33 mm/rev.). Subsequently, a confirmat-type furniture screw (7 mm major diameter, 4 mm minor diameter, 3 mm pitch) was screwed into these pilot holes. The ultimate SWR was measured with a universal testing machine. The results showed that the highest feed rate significantly decreases the SWR for all particleboards tested. This phenomenon can be attributed to the fact that a higher feed rate leads to a decreased precision in the internal surface of the pilot hole, consequently diminishing the screw’s anchoring capacity within the hole. The high feed rate, used to increase production efficiency, may significantly reduce furniture durability and usability.
The Dust Separation Efficiency of Filter Bags Used in the Wood-Based Panels Furniture Factory
The relationship between the conditions of the use of filter bags made of non-woven fabric and the separation efficiency of wood dust generated in a furniture factory was experimentally determined in the conditions of pulse-jet filtration using a pilot-scale baghouse as waste during the processing of wood composites. The experiments were carried out, and we describe the results of the experiment as consisting in assembling one type of filter bag in two dust extraction installations operating under different operating conditions in the same furniture factory. The filter bags working in the assumed time intervals were then tested for their separation efficiency using a stand for testing filtration processes on a pilot scale. The test results are presented in the form of graphs and tables describing both the characteristics of the dust extraction installations and the filter fabric used, as well as the separation efficiency of bags used at different times in different industrial operating conditions for each of them. The conducted research allowed us to recognize the phenomenon of filtration in relation to a very important value, which is the separating efficiency of dust extraction in various operating conditions of dust extraction installations in a furniture factory during the long-term use of filter fabrics. The obtained results allowed us to determine the separation efficiency for the tested bags at a level of over 99.99% and to state that this separation efficiency increased with the working time of the bag. The structure of the outlet dust from filters in the wood composites processing factory constitutes an element of the working environment if the purified air is returned in a recirculation circuit to the interior of the working area. Thanks to this, it is possible to predict the separation efficiency in the long-term use of filter dust collectors for wood dust in furniture factories.
Energy Consumption for Furniture Joints during Drilling in Birch Plywood
The purpose of this study is to support eco-design ideas and sustainable manufacturing techniques by examining the energy consumption related to drilling holes for different furniture connections. The experimental model is a simple piece of furniture made from birch plywood with three different types of joints. Eccentric joints, confirmat screws, and dowel measurements of energy consumption with a CNC drilling and milling machine show different values for every kind of connector. The energy consumption was measured using a portable power quality analyzer, specifically the PQ-box 150 manufactured by A:Eberle GmbH & Co. KG Nürnberg, Germany. This device likely adheres to industry standards for energy measurement, ensuring accurate and reliable results. The measurement process involved recording energy consumption at different stages of the machining process, allowing for the analysis of specific cutting work and total energy consumption for various joint types. Dowels exhibit the lowest energy consumption at 0.105 Wh for one furniture joint, confirmat screws at 0.127 Wh, while eccentric joints, despite their higher energy consumption (0.173 Wh), offer enhanced transportability and assembly flexibility of a piece of furniture. Specific cutting power for one selected piece of furniture was 227.89 J/mm3 for dowels, 190.63 J/mm3 for eccentric joints and 261.68 J/mm3 for confirmat screws.
The Flow Resistance of the Filter Bags in the Dust Collector Operating in the Line of Wood-Based Furniture Panels Edge Banding
The article describes the process of forming the wood dust filtration resistance generated during furniture production using the honeycomb board technology in a filtering installation operating in industrial conditions. The influence of the service life of the filter fabric on the filtration resistance values in industrial conditions for one installation and one type of filter fabric was analyzed. For this purpose, filter bags made of one type of filter material were used in an industrial filtering installation at four different times. The results were compared to those previously obtained at the same factory but with a different filter bag type. The analysis was based on the changes in the flow resistance of clean and dust-laden air through the filter fabric used at various times in the filtering installation of the narrow-surface treatment line in a furniture factory. This allowed for the determination of the dynamics and nature of changes in filtration resistance in industrial conditions for wood dust. The values of the dust resistance coefficient depend on the operating time and increased to the level of 20594 [s−1] for material A and from 6412.031 [s−1] to 10128.94 [s−1] for material B. The dimensional characteristics of the filtered dust and the technological conditions under which it was generated were also described.
Improving the stiffness of the corner connections in wooden door frames
The research aimed to determine the strength and stiffness of corner joints in interior door frames, depending on their construction and the modifications made to the design of the door frame joints. Initially, two models were compared: model 1, with two connectors using a clamping screw at an angle of 45°, and model 0, with a single connector using a cam joint at an angle of 90°. In all tests, model 1 exhibited significantly better mechanical properties. To improve the performance of model 0, three alternative construction models (A, B, and C) were proposed by changing the position of the door frame mounting holes. In the compression test, model A showed an increased bending moment compared to model 0, while models B and C showed no such improvement. In the tension test, the bending moment values remained at a similar level across all construction variants, including model 0. In terms of bending moment, the best result in compression was achieved by model A (48.26 Nm), and in tension by model B (48.72 Nm). The highest stiffness was demonstrated by model 1 (up to 42.38 kNm/rad), while among the alternative models, model C showed the best result in tension (33.98 kNm/rad). Due to the favourable increase in bending moment under compression in model A and the insignificant changes under tension across all variants, model A is considered the optimal solution. To enhance the strength of the door frame, offset holes can be applied as proposed in this model.
Long-term operation of pulse-jet filters for wood dust
Long-term operation of pulse-jet filters for wood dust. The study specifies the value of flow resistance and separation efficiency of filter material during long-term use in pulse-jet filters for wood dust. The experiments were carried out for one type of material working in two different filtration installations in one furniture factory. The bags were obtained from the installations after working for 67, 133 and 272 days, respectively. All tests were performed on the pilot-scale test stand under identical filtration conditions. Studies have shown that long-term filter material use increases airflow resistance and improves filtration efficiency. The range of these changes depends on the operating conditions of the pulse-jet filters. The obtained results made it possible to determine the properties of the long-term use of filter materials in various filtration conditions.
Screw Withdrawal Resistance from WPC Profiles Used in Door Frame Production
This study investigates the screw withdrawal resistance (SWR) of hollow wood–plastic composite (WPC) door frames, which serve as moisture-resistant alternatives to traditional wood-based materials. The tested WPC, characterised by a density of 1.33 g/cm3 and a polymer-bound lignocellulosic filler, exhibits superior dimensional stability and low water absorption—under 4% after 24 h of immersion. The research focuses on how the unique chambered geometry of these industrial profiles affects the anchoring of 20 mm conical wood screws used to mount essential fittings such as hinges and lock catches. The SWR was determined using a universal testing machine in accordance with the modified EN 320 standards. Results indicate that the installation location within the profile significantly dictates load-bearing capacity: the band profile (lock catch) achieved an average SWR of 525.65 N, while the beam profile (hinge) averaged only 275.25 N. This performance gap arises because screws anchor only into internal “ribs” rather than the full material depth. Since these values are considerably lower than those of traditional particleboard (~1364–1775 N), the study highlights a critical need to optimise screw dimensions to ensure the structural stability and safety of hollow WPC door systems.