One of the possible ways to transfer the tractive power of a drive unit to the traction element is to use fibre friction. When a steel rope is used as the traction element, there is a transfer of tractive power in the groove created on the perimeter of the rim of the driving rope sheave. The transmission capability of the drive is directly proportional to the size of the angle of wrap and the shear friction coefficient of the rope surface when the rope is in contact with the surface of the groove wall. The relationship for calculating the size of friction coefficient in the grooves is given by relevant technical standards. The coefficient of friction determined in this way does not take into account the state of possible operational contamination of the groove or the diameter of the rope used. Using a unique laboratory instrument, tensile forces were measured for both rope sides in the state of a non-rotating sheave or when the sheave started to rotate rope. Experimental measurements were carried out for two different diameters of steel ropes, which were guided by two types of grooves for the rope sheave under two limit operating states of the groove wall surface: clean and dirty with oil. By evaluating the measured tensile forces in the approaching and outrunning rope side girded with the groove of the rope sheave, it was found (using a measuring apparatus) that a rope of a larger diameter acquires a higher value of the friction coefficient for the groove than a rope of a smaller diameter. The coefficient of friction in the groove decreases with the increasing size of the sum of the acting tensile forces on both sides of the rope. Lower values of the coefficient of friction achieve semi-circular grooves, and V-shaped grooves show higher values. Lower values for the coefficient of friction, close to theoretical values which were calculated using the relevant relationships specified in the standards, were found for grooves contaminated with oil as opposed to dry and clean grooves.

This article discusses plasma cutting technology and its influences on the quality of the resulting cut. Plasma or a plasma arch consists of positive and negatively charged particles, excited and neutral atoms and molecules. As it contains free particles, it is electrically conductive and thus subject to the effects of the electrical and magnetic field. The basis of CNC machine design is described in the article, which has at least 3 axes (x, y, z), but there are also more technologically demanding applications, such as pipe cutting, profile and cutting using chamfer to prepare surfaces for welding, where these multi-axis devices are frequently used. The principle of plasma cutting and the plasma cutting phase is described in this article. The materials that can be divided by a plasma arc are described in detail, including graphs displaying the dependence of sheet thickness on the cutting speed. The article describes and lists the gases that are used in plasma-arc cutting, such as oxygen, argon, hydrogen and nitrogen. Important components of plasma cutting technology are the parameters that can be adjusted and set before the cutting so that the cut is of good quality. The most comprehensive chapter deals with the influences that affect plasma cutting quality. Cutting quality can be influenced by a number of factors. Everything starts with the proper choice of a CNC machine and a plasma source. The quality also depends on the expertise and experience of the machine operator and the setting of the plasma cutting parameters. This issue of influences on the plasma cutting quality is based on long-term experience in the field of the thermal cutting process.

In lifting systems used for the vertical transport of bulk materials and individual items or persons, so-called frictional force transmission between a steel cable and pulley is used. Due to the sufficient contact pressure between the pulley groove and the surface of the steel cable, the steel cable moves as a result of fibre friction. In general, it is possible to define fibre (also called belt) friction as the resistance that is imposed on a flexible steel cable sliding over the rounded surface of a pulley. The frictional transmission of the tractive force is considered safe if there is no slippage of the cable in the pulley groove. In the event of insufficient cable pressure against the pulley groove or insufficient friction, the transport process fails, and the lifting device is unable to perform its function. The purpose of the article and of the created measuring devices is to obtain by experimental measurements the most accurate true value possible of the coefficient of friction acting on the contact surface of the cable with the pulley groove. The values of the friction coefficients obtained by indirect measurements on laboratory equipment when the tractive force is transferred by friction differ in many cases and do not coincide with the values calculated using theoretical relationships. The aim of the paper is to present a method of measurement and to identify the magnitude of the forces acting on both sides of a cable belted in the V-groove of a cable drum. From the results obtained from the experimental measurements, to express the value of the random variable is based on the knowledge of the known values obtained from the measurements for their use in a failure analysis. This paper presents results that can be applied in the field of online monitoring of this type of lifting equipment for failure analysis, prediction and evaluation of their operational indicators.

Reverse engineering is the process of creating a digital version of an existing part without any knowledge in advance about the design intent. Due to 3D printing, the reconstructed part can be rapidly fabricated for prototyping or even for practical usage. To showcase this combination, this study presents a workflow on how to restore a motorcycle braking pedal from material SS316L with the Powder Bed Fusion (PBF) technology. Firstly, the CAD model of the original braking pedal was created. Before the actual PBF printing, the braking pedal printing process was simulated to identify the possible imperfections. The printed braking pedal was then subjected to quality control in terms of the shape distortion from its CAD counterpart and strength assessments, conducted both numerically and physically. As a result, the exterior shape of the braking pedal was restored. Additionally, by means of material assessments and physical tests, it was able to prove that the restored pedal was fully functional. Finally, an approach was proposed to optimize the braking pedal with a lattice structure to utilize the advantages the PBF technology offers.

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