Electrical steels are widely used in the electrical industry in the construction of many devices, e.g., power transformer cores and distribution transformers. An important parameter of electrical components that determines the efficiency of devices is energy loss during remagnetization. These losses are influenced, among other factors, by steel cutting processes. The common techniques for cutting electrical materials on industrial lines are mechanical cutting and laser cutting. High-pressure abrasive water jet (AWJ) cutting, unlike the technologies mentioned above, can ensure higher quality of the cut edge and limit the negative impact of the cutting process on the magnetic properties of sheet metal. However, the correct control of the process and the conditions of its implementation comprise a complex issue and require extensive scientific research. This work presents a new approach to cutting electric sheets, involving bundle cutting, which significantly increases the processing efficiency and the dimensional and shape accuracy of the cut details. The tests were carried out for bundles composed of a maximum of 30 sheets, ready to be joined in a stator and rotor in a motor. The influence of processing conditions on the quality of the cut edges of sheet metal, the width of the deformation zone, and the burr height were analyzed. The detailed analysis of the quality of the cut edges of electrical bundled sheets creates new possibilities for controlling the AWJ cutting process in order to obtain a product with the desired functional and operational properties.

This paper presents an original method for the comminution of polymetallic nodules in a hydro-jet mill of our own design, having the water jet pressure in the range of 70–200 MPa. The best comminution results are ensured by equipping the mill with a water jet having a diameter d_w = 0.7 mm and a comminution-homogenization tube having a diameter d_h = 2.4 mm, and by setting a distance s = 10 mm from the outlet of the homogenization tube to the comminuting disc. Particles of concretions comminuted under such conditions are characterized by a fairly regular isometric shape and favorable morphology represented by intense development of the specific surface.

Electrical steels are magnetically soft materials and are widely used in the electrical industry for the construction of power transformer cores, distribution transformers, current transformers, and voltage transformers. An important parameter of electrical components, which determines the efficiency of devices, is energy loss during remagnetization. Energy losses are caused by eddy currents, hysteresis, and magnetic delay associated with the low quality of the cut edge after the cutting of steels, and material deformations and excessive stress concentration in the surrounding cutting zones. Common techniques for cutting electrical materials in industrial lines include mechanical cutting and laser cutting. Work has shown that mechanical cutting of electrical steel single layers results in the occurrence of large deformation zones, and in cutting processes with a high-pressure abrasive water jet (AWJ), significant uplifts of material and burrs at the bottom edges of sheets occur. The problem of increasing the cutting quality was solved through selecting the stream parameters for bundle cutting of electrical steels. It has been shown that in the process of cutting electrical sheet bundles, the height of burrs on the cut surface and the zone of plastic deformation are reduced. The work also presents comparison and analysis of characteristic features of the cut edge of electrical sheets obtained through high-pressure abrasive water jet and mechanical cutting processes. The influence of the type and processing parameters on the characteristic features of the material hysteresis loop was determined.

This paper presents an original method for the micronization of coal particles in a hydro-jet mill, which allows effective comminuting of coal in the pressure range of 100–250 MPa, at a variable water flow rate of 0.2–0.5 dm³/s. The discussed high-pressure water jet mill (HPWJM) allows the comminution of standard fines, with a grain size up to 2 mm, and at a relatively high comminuting efficiency of 8 to 55 g/s. In addition, the paper presents energy-consumption ratios, and indicates the advantage of this method over mechanical grinding in a planetary ball-mill. At optimum conditions, coal comminution at an efficiency of Q_c = 38.4 g/s and at an energy input of E_H = 1.1 MJ/kg provides an average particle size of about 40 µm. The degree of comminution was further improved by applying roto-turbulent micronization, which resulted in an average size of comminuted coal particles of only 17 µm. As an additional result, the actual surface area of the particles increased by 10–30 thousand times when compared to ground fines—this fact is of significance for the application of micronized particles in quasi-liquid coal-water fuel.

The aim of this study was to analyze the effect of finishing methods on the surface quality of Ti-6Al-4V titanium alloy additively manufactured by selective laser melting. It was observed that among the finishing methods, water jet treatment did not produce significant changes, while the abrasive water jet proved effective in removing defects and smoothing the surface, especially at a pressure of 30 MPa. However, the risk of abrasive particle entrapment in the material was observed. Promising results were also obtained using the water–ice jet, which combines effective material removal with surface smoothing. The selection of the finishing method should be tailored to the application requirements. Further research will focus on optimization and the combination of techniques to improve the functional properties of titanium components.

This study investigates the use of shredded Pinus sylvestris (Scots pine) cones as a partial replacement for industrial wood chips in the surface layers of three-layer particleboards. Boards were produced at a density of 700 kg/m³ and thickness of 16 mm using urea-formaldehyde resin, with cone particles replacing 10–60% of wood chips in the outer layers. Mechanical tests showed that all boards met EN 312 flexural strength requirements, with up to 15% improvement in surface screw pull-out resistance at the highest cone content. SEM analysis revealed that pine cone particles have a complex, entangled fibrous structure, unlike conventional chips, enhancing mechanical interlocking with the resin. This improved interfacial bonding contributes to better stress transfer and reduced porosity in the outer layers. Additionally, boards gained unique aesthetic features from the natural coloration of cones. The results support the use of underutilized biomass for sustainable, structurally sound, and visually appealing wood-based panels.