The article presents the results of the development works and research on the atomization process carried out using two prototype high-power ultrasonic systems. Ultrasonic systems have been designed to develop a new metal powder production process; these materials are increasingly used in modern manufacturing processes such as additive technologies or spraying and surfacing processes. The preliminary studies presented in the article were conducted for water to assess the effectiveness of both systems and to verify the theoretical and structural assumptions. In ultrasonic atomization, the ultrasonic wave causes the phenomenon of cavitation, which leads to the overcoming of the surface tension forces of the liquid and its disintegration into fine droplets. The important parameters that affect the properties of the produced droplets include, among others, the frequency of the sonotrode vibrations and the amplitude of the vibrations of the working plate. As part of the research, the paper presents the process of selecting the sonotrode geometry for two different values of the transducer’s natural frequencies (20 kHz and 70 kHz). In the design process, the finite element method was used to perform a harmonic analysis and develop the geometry of the sonotrode and the working plate. The design assumptions and the design process were presented. The modeled and then ultrasonic waveguides were verified experimentally by measuring the deflection distribution on the working plate surface using a high-precision laser displacement sensor. Then, the work ultimately resulted in conducting atomization tests of water. The obtained aerosols and the mechanism of their formation were studied using a high-speed camera. Finally, using Matlab R2020a software and image analysis scripts, it was possible to analyze the droplet size distribution generated by both systems. It was observed that 50% of the produced droplets were in the range of 35–55 μm for a 20 kHz system, while for a 70 kHz system it was 10–25 μm, which is a very satisfying distribution in terms of metal powder atomization.

Multi Jet Fusion (MJF) is one of the newest additive manufacturing technologies for polymer powders, introduced in recent years. This fully industrial technology is gaining big interest as it allows fast, layer-by-layer, printing process, short production cycle, and very high printing resolution. In this paper, twelve thin-walled, spherical PA12 prints were studied in terms of geometry, dimensional accuracy, and fracture surface characteristics. The various characteristic features for MJF prints were observed here for parts produced according to four various print orientations and having different thicknesses, i.e., 1, 2 or 3 mm. The study showed that MJF technology can print such difficult shapes. However, the set of parameters allowing producing parts with highest geometrical and dimensional accuracy causes at the same time some microstructural issues, like great interlayer porosity or high number of non-processed powder particles embedded in the print structure.

Metal–plastic composites (MPCs) are gaining importance mainly due to high strength to weight ratio. They consist of three layers, two outer metallic cover sheets, and a plastic core. The presence of that inner plastic layer makes them rather unsuitable for joining by means of any conventional welding processes, which significantly reduces the application range of MPC. In this work, three various resistance spot welding (RSW)-based concepts were developed to overcome that limitation and join Litecor to DP600 steel. In all cases, a dedicated initial stage was implemented to RSW, which was aimed at removing the non-conductive polymer layer from the welding zone and creating the proper electrical contact for the resistance welding. These were, namely: (i) shunt current-assisted RSW; (ii) induction heating-assisted RSW; and (iii) ultrasonic-assisted RSW. The development of each concept was supported by finite element modeling, which was focused on setting the proper process parameters for polymer layer removal. Finally, the macro- and microstructure of exemplary RSW joints are shown and the most common spot weld features as well as the further development possibilities are discussed.

The article demonstrates an effective solution for ultrasonic quality monitoring of transmission and drive components of motor vehicles, joined using an innovative method called magnetically impelled arc butt welding (MIAB). The major challenge was the application of ultrasonic technology for quick and reliable testing of thin-walled components with complex geometry. To solve this problem the idea of using ultrasonic subsurface waves was investigated. By using finite elements method (FEM) the angle of the ultrasonic beam incident on the tested element and the frequency of the ultrasonic transducer were verified. Then, scanning acoustic microscopy (SAM) and X-ray computed tomography (CT), both nondestructive tests on thin-walled welded tubular components were performed. The research have shown that it is possible to detect defects with diameter of 0.3 mm with the angle of incidence of wave 31.5°. The results of the numerical analysis were compared with the experimental approach and confirmed the usefulness of proposed method. Finally, the potential of using immersion ultrasonic technique for quick and reliable validation of thin-walled tubular components was proven, as the test duration for a one elements was around 3 s.

This article presents research on advanced surface preparation methods for sintered carbides (WC-Co, grade B2) commonly used in the tool industry, particularly in the context of bonding these materials with C45 steel using adhesives. Sintered carbides are widely used due to their high hardness, wear resistance, and good ductility, making them ideal for manufacturing tools operating in harsh conditions. Traditional bonding methods, such as brazing and welding, often result in stresses and cracks. Adhesive bonding has therefore emerged as an effective alternative to mitigate these challenges. The research focuses on comparing the results obtained through modern surface treatment techniques, such as laser micro-texturing and plasma treatment, with traditional methods like grinding, abrasive blasting, and electrolytic etching. The influence of these methods on adhesion properties and the strength of adhesive bonds was evaluated through mechanical tests, including static shear and pull-off tests. An approximately 50% increase in the mechanical strength of adhesive joints was observed for surfaces treated with low-temperature plasma (operating voltage: 18 kV, flow of gasses: 20 l/min., treatment time: 60 s) and laser micro-texturing (infrared fiber laser, wavelength: 1064 nm (±5 nm), power: 20 W), as compared to mechanical grinding. The shear strength of the adhesive joints was equal to 32 MPa and 30 MPa on average in the case of treatment with low-temperature plasma made of helium and argon, respectively. The highest strength of an adhesive joint was equal to 34.5 MPa on average in the case of laser micro-texturing.

This article explores the possibilities of using non-destructive ultrasonic techniques to analyze the quality of lapped braze-welded joints. The tests were performed for 4 material groups (DC03+ZE steel and X5CrNi18-19 steel, aluminum alloys AW-5754 and AW-6061, titanium Grade 2 and copper Cu-ETP). As part of the work, additional materials and joint processes and its parameters were selected (TIG, MIG, laser). The quality of joints was monitored using scanning acoustic microscopy. Based on the A-scan andC-scan images, potential joints imperfections were determined. The possibilities of using advanced ultrasonic techniques to analyze the quality of braze joints was assessed.