In this paper, the fatigue behavior of polylactic acid (PLA) material with bamboo filler printed by 3D additive printing using fused deposition modelling (FDM) technology at different infill densities and print nozzle diameters is investigated. The mechanical test results are supported by the findings from SEM image analysis. The fatigue behavior was tested at four consecutive 250 cycles at loads ranging from 5 to 20, 30, 40, and 50% based on the limits found in the static tensile test. The results of the static tensile and low-cycle fatigue tests confirmed significant effects of infill density of 60%, 80%, and 100% on the tensile strength of the tested specimens. In particular, the research results show a significant effect of infill density on the fatigue properties of the tested materials. The influence of cyclic tests resulted in the strengthening of the tested material, and at the same time, its viscoelastic behavior was manifested. SEM analysis of the fracture surface confirmed a good interaction between the PLA matrix and the bamboo-based filler using nozzle diameters of 0.4 and 0.6 mm and infill densities of 60%, 80%, and 100%. Low-cycle testing showed no reductions in the mechanical properties and fatigue lives of the 3D printed samples.

Geopolymers compete with a number of conventional coatings and a few of them have already been replaced. The aim of this work was the analysis of alkali-activated metakaolin-based geopolymers and their use as brush-applied coatings, which were chosen due to their simplicity and cost-effectiveness. Eight coatings were prepared and the AlMgSi aluminum alloy underlying the substrate was also studied. The main characterizations of the prepared coatings were the microscopy analysis, which showed that manual painting with a brush on the coatings we prepared could achieve a high-quality geopolymer layer, and that if microscopic cracks are visible on the surface, they are uniform and do not affect the resulting cohesiveness of the coating. The thicknesses of these coatings are different, ranging from 1.5 to 11 μm, with no visible anomalies. For the evaluation of the properties of the coatings, we determined the analysis of adhesion to the adjacent substrate, microhardness and thermal expansion determined using the so-called dilatometric analysis as important criteria. For these analyses, the results vary by geopolymer type and are discussed in the following chapters.

Machining is an important part of the manufacturing process in the engineering field. Turning is one of these areas. At present, almost exclusively exchangeable cutting inserts are used in production machining. The article describes the research in the field of their wear, where the electron microscopy was used to evaluate the results. Electron microscopy is a very important aid in research in many areas not only of human activity and also is the important aid in the field of mechanical engineering and manufacturing technologies. The results thus obtained can make in a given area it clearer and better document the resulting situation. Within the experiments, selected cutting inserts (WPP10S, WPP20S) were used and the given material was machined (34CrNiMo6 steel). The cutting speed was different depending on the type of insert (WPP10S 120 and 140 m•min-1 , WPP20S 80, 100 and 120 m•min-1). The electron microscope Tescan Vega 3, which is available in the workplace where the experiment was conducted, was used to evaluate the resulting tool wear. As part of experiments was also realized the composition analyze of used cutting inserts. Analyzes of the machined material were also performed to confirm the declarations from the supplier.

This article deals with the comparative wear of CNMG-coated sintered carbide indexable cutting inserts by several manufacturers when turning 1.6582 steel hardened to 40–44 HRC. The main goal will be to demonstrate the different course of wear by testing seemingly identical inserts for engineering companies, showing the connection between the course of wear and the production of waste in the form of chips. The monitored type of wear was the flank wear VB_max of a cutting tool depending on the length of the machining time. Additionally, the effect of cutting tool wear on chip production, i.e., their quantity, shape and size, was monitored. For the purpose of mutual comparison, uniform cutting conditions were chosen on the basis of previous experiments, ensuring the stability of the given cutting process. For flank wear analysis, optical and electron microscopes were used. Meanwhile, a portable roughness tester was used to analyze the roughness of the machined surface. It was found that the quality of the interconnected coating layers has a perceptible influence on wear rate of the evaluated cutting inserts. The relation between the degree and characteristics of wear on the one hand, and the properties of the produced chips that identify the effect of the difference in the deposition layers using EDX/SEM analysis on the other, foreshadows the importance of choose between products with similarly declared properties was found. The current assessment of cutting tool wear and the evaluation of the chip produced has significant economic potential for manufacturing companies seeking to minimize costs.