The paper concerns the application a high-pressure abrasive waterjet (AWJ) for cutting the most commonly used rock materials such as granite, limestone, basalt and marble. Based on the analysis of the literature, the influence of parameters on the specific energy E_v, specific energy of cutting E_r and specific energy of intersection E_a was determined. Experimental studies were carried out on a laboratory test stand in accordance with a five-level rotating experiment plan. The results of the research were subjected to statistical processing, obtaining regression equations. The influence of the pressure and diameter of the abrasive waterjet on the energy consumption of rock cutting was tested. The effect of the stream power, feed speed and pressure on the cutting depth with the AWJ was also determined. The data obtained made it possible to evaluate the machinability of the rocks as a function of the power of the jet. These analyses were supplemented with charts illustrating the influence of the most important technological parameter of the cutting process, which is the feed speed. The presented results provide answers to the energy and time requirements for efficient cutting with the AWJ of frequently used rock materials.

This work describes the research aimed at determining the value of the basic parameters of fish cutting on treatment with a high-pressure water jet. Assuming a constant feed speed, distance of the nozzle from the processed raw material, and spray angle of the water jet for six diameters of the water nozzles, the supply pressure value was determined. Supply pressure at which the water stream has enough energy to fully cut the muscle flap is also determined. The tests were carried out on samples obtained from rainbow trout, considering the size of the carcasses and the place of cutting. Analysis of the obtained results showed that both the size of the carcass and the cutting site affect the value of the supply pressure. However, regardless of this, the full cut of the lobe without the skin can be obtained by feeding the jet with a pressure of 3.5 MPa. This amount of pressure can easily be achieved using a Karcher pressure washer. To effectively apply this technology to the fish processing industry, it is necessary to extend the tests with further processing parameters such as the feed speed of the nozzle.

This article concerns the application of the FEM method for the prediction of stress and deformation states in the workpiece during diamond sliding burnishing (DSB). An updated Lagrange (UL) description was used to describe the phenomena at a typical incremental step. The states of strain and strain rate are described by non-linear relationships without linearization. The material parameters were estimated during tensile tests to determine the characteristics of the 41Cr4 steel. Its hardness was also tested. Its aim was to prepare a table with the material properties of the above-mentioned steel and its implementation for numerical analyses. A Cowper–Symonds material model was used to model the displacement process of the wedge on an elastic/visco-plastic body reflecting the DSB process. The computer model was validated, and a good convergence of the results was obtained. Applications in the ANSYS/LS-Dyna program were developed to simulate the process of DSB. The results of numerical analyses were presented, among others, to explain the influence of the rake angle on the condition of the surface after machining, as well as the phenomenon of chip formation. The results of numerical simulations were verified experimentally on a test stand.

The paper presents the results of investigations into the possibility of using ahigh-pressure water-ice jet as a new method for removing a worn-out paint coating from the surface of metal parts (including those found in means of transportation) and for preparing the base surface for the application of renovation paint coating. Experimental investigations were carried out in four stages, on flat specimens, sized S × H = 75 × 115 mm, cut from sheet metal made of various materials such as steel X5CrNi18-10, PA2 aluminium alloy and PMMA polymethyl methacrylate (plastic). In the first stage, the surfaces of the samples were subjected to observation of surface morphology under a scanning electron microscope, and surface topography (ST) measurements were made on a profilographometer. Two ST parameters were analysed in detail: the maximum height of surface roughness Sz and the arithmetic mean surface roughness Sa. Next, paint coatings were applied to the specimens as a base. In the third stage, the paint coating applied was removed by means of a high-pressure water-ice jet (HPWIJ) by changing the values of the technological parameters, i.e., water jet pressure p_w, dry ice mass flow rate ${\dot{\mathrm{m}}}_{\mathrm{L}}$, distance between the sprinkler head outlet and the surface being treated (the so-called working jet length) l₂ and spray angle κ for the following constants: the number of TS = 4 holes, water hole diameter φ = 1.2 mm and sprinkler head length L_k = 200 mm. Afterwards, the surface morphology was observed again and the surface topography of the specimen was investigated by measuring selected 3D parameters of the ST structure, Sz and Sa. The results of investigations into the influence of selected HPWIJ treatment parameters on the surface Q_F removal efficiency obtained are also presented. Univariate regression functions were developed for the mean stripping efficiency based on the following: dry ice mass flow rate ${\dot{\mathrm{m}}}_{\mathrm{L}}$, working jet length l₂ and spray angle κ. Based on these functions, the values of optimal parameters were determined that allow the maximum efficiency of the process to be obtained. A 95% confidence region for the regression function was also developed. The results demonstrated that HPWIJ treatment does not interfere with the geometric structure of the base material, and they confirmed the possibility of using this treatment as an efficient method of removing a worn paint layer from bases made of various metal and plastic materials, and preparing it for applying a new layer during renovation.

The article presents the concept of constructing a mobile trolley designed for transporting a tire changer. Its main feature is easy assembly and disassembly. So that, it is possible to store the dismantled device when it is not in use. In this way, it occupies very little space in the workshop. The use of CAD systems has enabled the development of geometry of spatial models and carrying out the necessary strength analyzes of the developed structure.

The article presents the concept of constructing a bicycle frame made of profiles and universal connectors, so that the user can build a frame adapted to his height. The geometry of spatial models was developed and the durability of the proposed solutions was analyzed.