National Repository of Grey Literature 41 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Determination of anodizing parameters for surface properties of aluminum alloys
Paclík, Eduard ; Vaverka, Ondřej (referee) ; Košťál, David (advisor)
The bachelor's thesis deals with the determination of basic parameters for anodizing aluminum alloys. The introductory passages include an overview of aluminum alloys suitable for anodization, theoretical and practical assumptions of anodic oxidation. The main experimental part discusses the laboratory anodic oxidation of aluminum alloy samples under different parameters of surface roughness, current density, and voltage. Anodically oxidized samples were tested on special UMT tribometer and Contour GT-X profilometer devices for friction coefficient measurement and surface inspection. The measurement results were used to determine the dependence between surface roughness of aluminum alloys and the quality of the anodized layer, the dependence between current density of the anodic process and the quality of the anodized layer, and the dependence between voltage and the quality of the anodized layer. The problem was solved within the possibilities of FSI laboratory conditions. The thesis serves as a basic orientation in this field.
Topology optimization of a quadcopter arm using 3D print
Simon, Jakub ; Červinek, Ondřej (referee) ; Vaverka, Ondřej (advisor)
This bachelor thesis deals with the comparison of manufacturing constraints applied during topology optimization of a demonstration component, which was a quadcopter arm. Four designed arms were optimized, each with different manufacturing constraints: Extrusion, Single draw, Split draw, Overhang and one arm only with symmetry plane, without any other manufacturing constraint. For all designs, it was important to maintain a continuous geometry during optimization and that final weight approximately equals to the weight of the original arm. All five arms were then subjected to static structural analysis with the finite element method. After that, arms were printed using Fused deposition modelling (FDM) from ABS material and then tested by static force. The photogrammetry method was used to evaluate deformation. Results of the experiment were recalculated to relative stiffness, where small differences between weights were considered. Relative stiffnesses of designed arms were then compared, showing that 4 out of 5 topology optimized arms have higher stiffness than the original shape. The toughest design is without manufacturing constraints which at the same weight has 12.5 times higher relative stiffness than the original arm.
Effect of layer thickness on critical angle of additively manufactured lattice structures
Nosek, Jakub ; Vrána, Radek (referee) ; Vaverka, Ondřej (advisor)
Aim of this work is to describe the effect of a layer thickness on critical angel of a lattice structures manufactured by SLM technology. The effect of layer thickness was investigated on single struts and on lattice structures made from stainless steel 316L. Better geometrical accuracy could be obtained, if the smaller layer thickness is used. Less attached powder particles on downskins was also observed on lattice structures. Thanks to this thesis, it is possible to determine, if it is meaningful to decrease the layer thickness in order to improve manufacturability of lattice structures even with higher manufacturing time.
Heat treatment of maraging steel processted by SLM
Valenta, Jakub ; Vaverka, Ondřej (referee) ; Koutný, Daniel (advisor)
The bachelor thesis deals with the study of the heat treatment of the maraging steel 1.2709 (DIN X3NiCoMoTi18-9-5). The first part of the work is survay of studies that focus on heat treatment of maraging steel made by forging or Selective laser melting technology. Based on that section, a heat treatment was designed by which the samples manufactured on ProX 300 from company 3D Systems and M2 Cusing from company Concept Laser were treated. The effect of heat treatment on the mechanical properties of the samples was subsequently tested by tensile testing and metallographic analysis. The test results of both sets of samples were compared with each other and with the results of other studies and the impact of the described heat treatment on the material was evaluated.
Design of a lightweight manipulator for a robotic arm
Eim, Jakub ; Ržonca, Michal (referee) ; Vaverka, Ondřej (advisor)
The bachelor’s thesis describes the design and manufacturing process of a lightweight and modular manipulator for Scara robotic arms made by Epson. The review part is focused on currently used heavy manipulators and contemporary possibilities of connecting carbon fibre profiles. The practical part of the thesis aims on deliberation about geometry of the manipulator assembly using FEM (Finite element method) and the manufacturing of the assembly. The thesis concludes with a comparison between the currently used heavyweight and the new manipulator assembly. The weight of the assembly has been reduced by 56 % while maintaining sufficient firmness. In the appendix are included CAD (Computer-aided design) files, technical drawings of individual parts and photodocumentaries of the whole process.
Development of a strategy for 3D printing of copper using Laser Powder Bed Fusion
Kryšpín, Vojtěch ; Vaverka, Ondřej (referee) ; Malý, Martin (advisor)
Copper sees vast usage in aeronautical, electrotechnical and energy industries due to its excellent machinability and thermal and electrical conductivity. In combination with modern computational approaches such as topological optimalization, additive manufacturing of copper has a great potential. My work has focused on creating a sample with the highest relative density through the application of recoating and remelting strategies. The best specimens which reached relative density over 99,1% were created with the following printing parameters: LP = 400 W, LV = 400 m·s-1 a HD = 0,01 mm.
Design of an experimental manifold suitable for a 3D print manufacturing
Zeman, Stanislav ; Křivohlavý, Petr (referee) ; Vaverka, Ondřej (advisor)
The target of this thesis was to design a method of mounting pressure sensors on an already designed shape of a flow distribution header. Furthermore, it was necessary to design a method of mounting the header on a laboratory stand and then find a method of surface treatment. This thesis was solved in these three structural nodes. Gradually, three variants were designed for the threaded connection of the distributor and the pressure sensor and then three variants of installation were designed for the selected threaded connection. The possibilities of mounting a header on a laboratory stand were designed in two variants. Finally, possible methods of surface treatment have been proposed to improve the impermeability through the wall of the header. The individual variants in each design node were compared with each other by their strength and the result was the final design of the flow distribution header. It was manufactured according to the given technological procedure and then its functionality was tested.
Testing of parts produced by Bound Metal Deposition technology
Hradil, Antonín ; Vaverka, Ondřej (referee) ; Koutecký, Tomáš (advisor)
Bachelor thesis on the topic Testing of parts produced by Bound Metal Deposition technology. Aim of the work is to obtain mechanical properties of products made by Studio System. We have achieved this by performing tensile test and optical metallography. The results of this thesis are mechanical properties of the tensile test. Re, Rm, E, etc. Another results are microscopic images of microstructure of material. Thanks to this work, we are getting closer to the technology Bound Metal Deposition. We approximate scientifically its mechanical properties and the microstructure of the product surface.
Optimization of axle carier for formula student for SLM fabrication
Vaverka, Ondřej ; Růžička, Bronislav (referee) ; Koutný, Daniel (advisor)
This diploma thesis deals with design of axle carrier for Formula Student. The axle carrier is topologically optimized and additively manufactured with Selective Laser Melting technology. Material for its production is aluminium alloy AlSi10Mg, which has worse mechanical properties than commonly used high-strength alloys. Therefore the aim was, by using topology optimization, to design a component, which would have comparable properties with milled component. The stress strain analysis was carried out by the finite element method and maximum deformation and safety coef-ficients were acquired. The prototype was made and its dimensions were controlled by optical digitization, which proved accuracy of manufacturing. The strength calcu-lations were verified by special testing device and photogrammetry measurement. The load during the tests was 20 % higher than in the analysis and no limit state was observed. This verified its safety and functionality.
Topology optimisation using lattice structures
Černák, Martin ; Maňas, Pavel (referee) ; Vaverka, Ondřej (advisor)
This thesis aimed to develop and verify the methodology for lattice topology optimization, which deals with additive manufacturing specifications and is independent of the optimization solver. The developed methodology uses the SIMP topology optimization algorithm. The penalization factor used for a solution is based on the mechanical properties characterizing arbitrarily chosen unit cell. These are identified using the homogenization method applied to the real geometry specified by 3D optical digitization. Verification is based on FEA using the variable homogenized properties. The local stress response is simulated by submodeling technique. The methodology was verified by optimizing the braking shield bracket of a plane. The optimized part is 22 % lighter and 31 % stiffer than the original solution. Results of the thesis demonstrate that the proposed methodology is suitable for structural part optimization and allows us to use lattice structures together with topology optimization and additive manufacturing relatively easily, not only in the space industry.

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