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Processing of aluminium alloys using 3D technology selective laser melting
Měchura, Lukáš ; Koutný, Daniel (referee) ; Paloušek, David (advisor)
This bachelor thesis deals with finding of appropriate process parameters for minimizing porosity with SLM technology for processing aluminum alloy 6061. The search part deals about the issue of additive manufacturing aluminum alloys and evaluation of porosity measurements of relative density. Based on general knowledge were proposed test samples produced by sintering of metallurgical powder using a laser with ytterbium optical fiber. In this work was used high power of laser up to 400 W, with which 6061 alloy was not been in terms of porosity in detail tested yet. As the result, the technological parameters dependence on relative density and the overview of this alloy processing by SLM technology was determined.
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Review of materials used for the manufacturing by the Selective Laser Melting technology
Skalický, Petr ; Vrána, Radek (referee) ; Koukal, Ondřej (advisor)
This bachelor thesis aims to provide an overview of metallic materials (powders), which are used in the manufacture of parts and models with SLM (Selective Laser Melting) technology. It contains basic information about Rapid Prototyping (RP) technology and more detailed description of basic methods of RP, especially SLM. Next is a description of manufacture powders methods and its properties. The last section contains an overview of powdery materials as powders made of pure metal (one kind of metal material) and powders produced from metal alloys. This review focuses on the most important and most widely used materials for the manufacture of parts using SLM.
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Process Parameters Development for Producing of Lattice Structures Using 3D Metal Printing
Moravčik, Jaroslav ; Koutný, Daniel (referee) ; Vrána, Radek (advisor)
Selective laser melting (SLM) belongs to additive technologies. Progressive adding of layers of material powder and creating the structure with laser beam allows to create components with complex shapes, for example microstructures. This thesis explores potential of new printing strategies, which could lead to good melting of printed component and reaching to better structure without porosities. Based on analysis of actual state, software for calculation of laser trajectory was made with use of new printing strategy. Also, process parameters obtained from technical articles and from experiments made on Institute of Machine and Industrial Design on Faculty of Mechanical Engineering BUT in Brno were compared. This comparison led to suggestion of test set of components with new parameters and strategies. This set could lead to new researches in this issue.
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Support structures for 3D printing from metallic materials
Hruboš, David ; Vrána, Radek (referee) ; Koutný, Daniel (advisor)
This bachelor’s thesis deals with additive technology selective laser melting, which allows creating 3D objects from metal powder. The support structures are required in this process to dissipate process heat and anchor the part to the base plate. Four new types of support structures were designed in this work. The functionality of the structures was verified and mechanical properties of structures were compared in a strength test.
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Processing of NiTi alloy by SLM technology
Lukačovič, Samuel ; Dočekalová, Kateřina (referee) ; Koutný, Daniel (advisor)
This thesis deals with development of process parameters suitable for processing nickel titanium alloy, also known as nitinol, using technology Selective laser melting. The main goal of this thesis is development of process parameters capable of producing dense and thin wall parts. Minor goals are description of effect of process parameters on chemical composition, thermomechanical and mechanical properties of printed parts. By analyzing the experiments carried out on single tracks, dense parts and thin walls, the optimal combination of process parameters was able to be determined. Using this combination, it was possible to produce non-porous dense and thin wall parts, which exhibit superelasticity under load. The effects of process parameters on nickel evaporation and transition temperatures were described using analyses of thermal response and chemical composition.
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Design of auxetic structures for the selective laser melting technology
Pchálek, Václav ; Hutař, Pavel (referee) ; Červinek, Ondřej (advisor)
With the development of additive technologies, it became possible to produce auxetic structures with complicated geometries. Despite their intensive study, their potential for high resistance to local loading has not yet been explored. Describing this phenomenon and its causes would enable the effective design of structures with greatly enhanced resistance to foreign object impact. Therefore, this work investigated the deformation behavior of auxetic re-entrant honeycomb structures under local loading. The relationship between the resistance of the structure to local loading and the magnitude of the negative Poisson´s number, which was controlled by the geometry of the basic cell, was investigated. An analytical approach was used to determine the Poisson´s number of the structures. Subsequently, a prediction of the local loading behaviour of the structures was made using the finite element method assuming small and large deformations. This behavior was then experimentally verified for small and large strain rates on structures fabricated by selective laser melting technology. It was found that for the assumption of small deformations, the smaller the Poisson´s number of the structure, the more resistant it is to local loading. However, this does not apply to the assumption of large deformations, where the wall interaction and its buckling were difficult to predict. Furthermore, structures with thinner walls were shown to deform more, thus using their full deformation potential and therefore being more resistant to local loading. When tested at both low and high strain rates, a rearrangement of the structure towards the impact location was observed in two directions, perpendicular and against the direction of loading. It was found that structures with different geometry but the same Poisson's number have the same deformation behavior in terms of strain rate and reaction force. The findings of this work contribute to the understanding of the behaviour of auxetic structures under local loading, which can be used in the design of such loaded structures in specific applications.
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Surface roughness of lattice structures produced by SLM technology
Bóssi, Adam ; Malý, Martin (referee) ; Jaroš, Jan (advisor)
Selective laser melting (SLM) is an additive manufacturing technique (AM), that allows production of complex geometries that can be found in lattice structures. Processing of magnesium-based materials with this technology is difficult because of their high reactivity. This bachelor’s thesis clarifies the effects of processing parameters (laser power and laser scan speed) on surface roughness of lattice structures. The theoretical part of this thesis deals with the issue of magnesium alloys and manufacturing of lattice structures. The practical part of this thesis contains the design of the experiment and evaluation of the given experiment. Based on the results of the experiment, the dependencies of process parameters were made on surface roughness and incline angle of struts. The main takeaway of this thesis for the reader is in familiarization with the issue of process parameters and their effect on surface roughness in lattice structures.
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Micro-lattice structures with variable strut diameter
Brulík, Karel ; Jaroš, Jan (referee) ; Červinek, Ondřej (advisor)
Due to their specific properties, micro-lattice structures have a great potential for use in energy absorption applications. It turns out that conventional micro-lattice structures with constant volume fraction can be designed for a known amount of absorbed energy. In real applications, however, we often do not know it in advance. Therefore, the use of functionally graded micro-lattice structures, which can be designed for a wider range of applied energies, appears to be more promising. The aim of this work is to compare micro-lattice structures with variable strut diameter made from 316L stainless steel by Selective Laser Melting technology in terms of energy absorption capability. For this purpose, two types of structures, F2BCC and F2BCC_45, were fabricated, both in configuration with constant, continuously variable and stepwise variable strut diameter. The structures were subsequently dynamically loaded using a drop-weight test, the results of which were described by the time history of deformation and forces. The greater amount of absorbed energy was measured for structures of type F2BCC_45, up to 73 % depending on the configuration of the structures. The results revealed that the variable strut diameter does not have a large effect on the amount of absorbed energy, but it significantly reduces the shock generated, up to 54 % depending on the type and configuration of the structure. This thesis provides a comprehensive view of the deformation and stress characteristics of both types of structures, and in particular a comparison of the effect of variable strut diameter.
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Processing of metallic materials by Selective Laser Melting at elevated temperatures
Malý, Martin ; Filho, Sergio de Traglia Amancio (referee) ; Dr. Michael R. Tucker (referee) ; Koutný, Daniel (advisor)
Tato disertační práce se zabývá vlivem předehřevu na výrobu komponent 3D tiskem kovů technologií Selective Laser Melting (SLM), také známou pod označením Laser Powder Bed Fusion (LPBF). V práci je obsažen přehled současného stavu poznání v oblasti realizace předehřevu a fyzikální podstaty předehřevu. Dále je v práci obsažen přehled vlivu předehřevu na konkrétní typy materiálů. Mezi tyto typy materiálů byly zařazeny titanové, intermetalické, niklové a hliníkové slitiny a měď. Z rešeršní části byly identifikovány perspektivní oblasti, které doposud nebyly dostatečně zkoumány, a kde by předehřev mohl vést k zefektivnění technologie LPBF a rozšíření oblasti zpracovatelných materiálů. Mezi tyto oblasti bylo zařazeno zkoumání vlivu předehřevu v kombinaci s dalšími procesními parametry na zbytková napětí u slitiny Ti6Al4V, vliv předehřevu na niklovou slitinu Inconel 939 a na měď. Předpokladem u Ti6Al4V a Inconelu 939 bylo, že předehřev sníží zbytková napětí a bude tak možné snížit množství podpůrných struktur během výroby, což by vedlo k zefektivnění technologie. Tato hypotéza byla zamítnuta, protože i přes snížení zbytkových napětí u Ti6Al4V nedošlo k jejich eliminaci a navíc, došlo k rychlé degradaci nepoužitého prášku, což zvyšuje náklady na výrobu. U Inconelu 939 dokonce zvýšená teplota vedla k vyšším deformacím, a tedy zbytkovým napětím v důsledku evoluce karbidické fáze. Další perspektivní oblastí, kde by předehřev mohl vést k zvýšení portfolia zpracovatelných materiálů, je měď. Měď je díky vysoké tepelné vodivosti a odrazivosti laserového záření považována za obtížně zpracovatelnou technologií LPBF. Z experimentů byl potvrzen velice pozitivní vliv předehřevu na relativní hustotu vzorků. Vzorky dosáhly hodnot relativní hustoty přes 99 % pokud byly tisknuty s předehřevem 400 °C. Bylo tedy experimentálně ověřeno, že předehřev může významně zlepšit zpracovatelnost skupiny materiálů, které mají nízkou pohltivost laserového záření a materiálů s vysokou teplenou vodivostí. Všechny výsledky vedou k lepšímu pochopení chování materiálů během zpracování technologií LPBF a mohou vést k jejímu rozšíření do dalších průmyslových odvětví. Výsledky jsou shrnuty ve třech publikacích, které byly vydány ve vědeckých časopisech.
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