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The goal of this study was to determine the effect of cutting methods on the edges of selected materials applied in structural elements and floor sheathing of unmanned air vehicles. Three cutting methods for MGS L285 epoxy resin composites used for production of unmanned air vehicles manufactured in one of the European companies were presented. Composites reinforced by glass and aramid fibres are approved for certified production of air vehicle elements (AMC-20). Cutting was applied to each material using different technologies, such as: milling, laser cutting and abrasive water jet cutting. The authors focused on the edge quality of the tested specimens cut using various methods. Quality assessment was based on electronic microscopic scanning images and measurement of the specimen maximum damage. In summary, the choice of an appropriate composite cutting method depends on the type of material and its parameters, and it is crucial for the quality of the machined product. The authors focused on determining the selection of parameters for chosen cutting methods and materials used in the military unmanned aerial vehicle industry. Among the conducted tests, the results indicate that better cutting effects are obtained for milling methods in the case of GFRP + L285 (0.143 ± 0.073 µm) and CFRP + L285 (0.072 ± 0.027 µm), and the worst for AFRP + L285 (0.831 ± 0.269 µm). The water jet method gives the worst results in the cutting zone (results above 0.224 μm). [ABSTRACT FROM AUTHOR]

Metal powder 3D printing technology is gaining popularity due to the possibility of producing structural elements of complex geometry, which production with the methods used so far is difficult or impossible to obtain. An example of a material used in the parts production by the additive method is 316L steel, which is used in the production of bone support screws, surgical tools and needles, or in other industries for the production of exhaust manifolds, parts of furnaces or heat exchangers. The study investigated the mechanical properties, hardness and microstructure of 316L steel produced in the selective laser melting process (SLM). Based on the tests, the following mechanical properties of 316L steel were obtained: Su = 566.7MPa, Sp0.2 = 484MPa, E = 113820MPa, A = 79.5%, Z = 72.3%. The hardness test results show a significant increase in hardness as the tensile test approaches the sample fracture. The structure of 316L steel in the grip part is characterized by the formation of visible semi-elliptical zones of the material alloy, the pools with crystallized grains with a cell-column structure oriented in the direction of the thermal gradient. This type of microstructure is characteristic of technology in which, after solidification, the cooling process takes place at high speed.

The aim of the article was to carry out FEM strength tests for four proposed by the authors geometry of the intraoral implant. Change of their geometrical features to find the most optimal distribution of reduced stresses. The article presents various geometries of the new dental implant. Strength tests were performed using the finite element method (FEM). The results of the tests were analyzed and their assessment was made for which of the solutions of the new geometry the stress distribution is the most optimal. Detailed results of the analyzes for a given model are shown and new solutions in the construction of the implant are proposed.

Conventional construction of components is slowly being replaced by rapid prototyping and the use of DMLS technology. The development of DMLS requires conducting experimental studies that build a knowledge base that allows for the averaging of mechanical properties. verification of how the initiation of the crack occurs in the material and how the energy is propagated in the samples that were made by a conventional method compared to the samples, where the method of sintering titanium layers will be used. The literature analysis showed no research results relating to the impact of values of strength parameters on the structure of materials produced by the DMLS method. Titanium samples made with the additive method and the conventional titanium grade 5 Ti6Al4V titanium method, which is used, among others, in medicine, were used for the tests. The article presents the influence of material structure on mechanical properties (Re, Rm, A, Z). The presented research is preliminary research defining the properties of the material, which are gaining more and more application by using the DMLS method in the construction of machines and in medicine.

Zirconium dioxide is a material known over 60 years, used for the production of ceramic and hybrid bearings and in dentistry: bows, crowns, and bridges. For testing the strength of zirconium dioxide, normative samples were made, which were subjected to strength tests. Microscopic analysis of sample fracture was performed. In addition, zirconium oxide is an easy to process material. Zirconium dioxide is a polymorphic material exhibiting three phases: monocyclic, cubic and tetragonal. In addition, during propagation of cracks, the material shows a strengthening transformation; replacement of phase and increase of the volume of molecules that inhibit microcracks in the material. For a better illustration of the destruction of the samples, a two-parameter analysis of the Weibull distribution was made, which, as shown in the literature review for this type of research is standard. This analysis is described in the standard related to statistical analysis of advanced ceramics. The paper presents the original technology of making zirconium dioxide samples, tests of strength on a servo-hydraulic machine Instron 8874 and microscopic analysis of the obtained results.