Experiments with changes in motion geometry can provide valuable data for engineering and development purposes, allowing a better understanding of the influence of tribological factors on the performance and service life of joints. The presented subject article focused on the experimental investigation of the influence of the geometry of the movement of the friction process on the change in the tribological properties of 30CrNiMo8 steel. The friction process was carried out without the use of a lubricant in contact with a steel ball of G40 material with a diameter of 4.76 mm. The steel ball performed two types of movement on the surface of the experimental material. The first method used was ball on disc, in which the ball moved reciprocally in an oval direction at an angle of 180° on a circumferential length of 35 mm at a speed of 5 mm/s. The second method consists of the same input parameters of the measurement, with the difference that the path along which the ball moved had a linear character. The load during the experiment was set at a constant value of 50 N with 1000 repetitions. The results show that with the ball on disc method, there was an increase in wear by 147% compared to the linear test method, which was approximately a coefficient of increase in wear of 2.468. EDS analysis pointed to the occurrence of oxidative wear that affected the resulting COF values, which were lower by 8% when using the ball on disc method due to a more uniform distribution of O and C on the surface of the friction groove where these elements acted as solid microlubricants. With the ball on disc method, defects in the form of microcracks occurred, which affected the reduction in the values of the depth of the affected area of microhardness.

The presented study focuses on the study of polylactide acid (PLA) material, which is a frequently used material in 3D printing. Surface modification using DCSBD plasma discharge is proposed as a way to improve the adhesion between individual layers of material. Adhesion is a critical factor for achieving high-quality print output, as low adhesion can cause individual deposited layers of material to separate and ripple during printing. Dynamic Mechanical Analysis (DMA) is used to determine the glass transition temperature (Tg) of a material. Tg is important because it determines how difficult the material is to print, the closer the Tg is to room temperature, the easier the material is to print. However, after printing a layer of material and subsequently cooling it to room temperature, the material begins to shrink and wave due to the change in material expansion. This can have a negative effect on the adhesion between the layers of the material, which can lead to separation of the layers. The presented study tries to find a way to improve the adhesion of individual layers of material. Surface modification by plasma discharge appears to be a promising method that could improve the adhesion between individual layers of PLA material.

The presented work deals with the investigation of mechanical tribological properties on Inconel 625 superalloy, which is welded on a 16Mo3 steel pipe. The wall thickness of the basic steel pipe was 7 mm, while the average thickness of the welded layer was 3.5 mm. The coating was made by the cold metal transfer (CMT) method. A supercritical bending of 180° was performed on the material welded in this way while cold. The mechanical properties evaluated were hardness, wear resistance, coefficient of friction (COF) and change in surface roughness for both materials. The UMT Tribolab laboratory equipment was used to measure COF and wear resistance by the Ball-on-flat method, which used a G40 steel pressure ball. The entire process took place at an elevated temperature of 500 °C. The measured results show that the materials after bending are reinforced by plastic deformation, which leads to an increase in hardness and also resistance to wear. Superalloy Inconel 625 shows approximately seven times higher rate of wear compared to steel 16Mo3 due to the creation of local oxidation areas that support the formation of abrasive wear and do not create a solid lubricant, as in the case of steel 16Mo3. Strain hardening leads to a reduction of possible wear on Inconel 625 superalloy as well as on 16Mo3 steel. In the case of the friction process, the places of supercritical bending of the structure showed the greatest resistance to wear compared to the non-deformed structure.

In connection with the growing importance of the efficiency and reliability of tools in industrial sectors, our research represents a key step in the effort to optimize production processes and increase their service life in real conditions. The study deals with the comparison of the tribological properties of three tool steels, two of which were produced by the powder metallurgy method—ASP2017 and ASP2055—and the last tool steel underwent the conventional production method—X153CrMoV12. The samples were mechanically machined with the finishing technology of turning and, finally, heat treated (Q + T). The study focused on the evaluation of hardness, resulting microstructure, wear resistance, and coefficient of friction (COF). The ball-on-disc method was chosen as part of the COF and wear resistance test. The tribological test took place at room temperature with dry friction to accelerate surface wear. The pressing material was a hardened steel ball G40 (DIN 100Cr6). Measurements were performed at loads of 10 N, 6 N, and 2 N and turning radii of 13 mm, 18 mm, and 23 mm, which represents a peripheral speed of 0.34, 0.47, and 0.60 m/s. The duration of the measurement for each sample was 20 min. The results showed that the COF of powder steels showed almost the same values, while a significant difference occurred with the increase of the radius rotation in the case of conventional steel. The results within the friction mechanism showed two types of wear, namely, adhesive and abrasive wear, depending on the Q + T process. From a tribological point of view in terms of wear, it was possible to state that the material ASP2055 after Q + T showed the lowest rate of wear of all the tested steels.

The presented work deals with the study of the effect of increasing the doses of irradiation by accelerated electrons on the sliding properties of polymer materials. Due to the influence of radiation, surface roughness changes occur on the surface of the experimental materials, which lead to changes in the properties of the coefficient of friction on the selected polymer materials. Three types of polymer materials PET, PTFE and PE2000C were used for the experimental research, which, due to their properties, are used for different types of sliding products. A steel ball of G40 material was used as a pressure material, which moved along a linear path on which the load was increased from 10 N to 100 N. Electron beam accelerators with the conversion of electrons to X-rays combine the advantages of a high ability to penetrate gamma photons sources and high performance of electron beam devices. The application possibilities of the device are wide due to the dual mode of operation (electron beam or Xray beam) and a wide range of applicable doses and also dose rates.

The aim of this study is to investigate the effect of oscillatory loading frequency on the dynamic-mechanical properties of 3D printed thermoplastics, namely acrylonitrile-butadiene-styrene (ABS), glycol-modified polyethylene terephthalate (PE...