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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.
Influence of Ion Implantation on the Wear and Lifetime of Circular Saw Blades in Industrial Production of Wooden Door Frames
The paper presents the effect of nitrogen ion implantation on tool wear and tool life during the sawing of wood-based materials in the industrial production of door frames. The circular saw blades used in machining had WC-Co carbide teeth. Saw teeth were modified by ion implantation. The total implanted dose of nitrogen ions was 5 × 1017 cm−2 (2 × 2.5 × 1017 cm−2) and ions were implanted at 50 kV acceleration voltage. Tool wear testing was carried out under industrial production conditions for the door frames made of wood-based materials. The wear of circular saw teeth was evaluated under an optical microscope. Based on the tool’s wear and machining distance, a mathematical linear model of the non-treated and ion-implanted tools’ life was developed using the linear least squares method. The study showed less wear of the implanted circular saw blades and a significant increase in the estimated lifetime of modified tools compared to non-treated (control) tools. At the same time, activation of the surface of the implanted circular saw teeth was observed, manifested by an increase in adhesion and the appearance of the secondary structures on the WC-Co surface.
Efficiency of integrated technological modules in mass production processes of wooden door frames
The efficiency of the formatting and milling module of the technological line for door frames production
By introducing a new technological line for formatting and milling mass-customized door frames for wooden doors, PORTA KMI Poland with an industrial plant located in Ełk, Poland, conducted appropriate performance tests of the line to determine the production capacity during technological acceptance in order to check whether the assumed capacity was met before its technical acceptance takes place. The work describes how the processing time changes for frames with changed beam lengths from the reference length of 2028 mm to 2600 mm and for frames whose width has been increased from 127 and 147 mm to 500 mm. On this basis, an average time of 25.53 s was calculated for door frames with beams 2600 mm long and 28.1 s for door frames with a width of 500 mm. Efficiency was also calculated, which is 2.35 for frames with a changed beam length of 2.14.