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Development of 3D metal printing process parameters for producing of the lattice structure
Jaroš, Jan ; Koutný, Daniel (referee) ; Vrána, Radek (advisor)
Selective laser melting (SLM) in additive technology, which allows production of lattice structures. Lattice structures are very difficult to produce using conventional methods. The main use of lattice structures is in aerospace industry and medicine for bone implants production. In this work influence of processing parameters (laser power, scanning speed) on properties (diameter, surface roughness, porosity) of struts is investigated. The processing parameters selection was based on single tracks test. In the first test, ImageJ was used to determine porosity of struts. In the second test porosity was analyzed with more accurate µCT technology. Both tests used 3D scanning technology to determine dimension accuracy and surface roughness of samples. The measurement results led to the detection of processing parameter „window“ where samles had the best combination of surface roughness and porosity. The best results were achieved with 225-275 W laser power and scanning speed of 1400-2000 mm·s-1.
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Comparison of micro-lattice structures for energy absorption
Koban, Tomáš ; Vrána, Radek (referee) ; Červinek, Ondřej (advisor)
Additively manufactured metal micro-structures have great potential in energy absorption applications. The recent research in this field led to a much better understanding of failure behaviour of these micro-structures. This thesis focuses on comparison of energy absorption ability of strut-based micro-lattice structures manufactured by selective laser melting depending on their topology and basic material. Energy absorption of three types of lattice structures (BCC, BCCZ, GBCC) made from stainless steel 316L and aluminium alloy AlSi10Mg was examined. Specific energy absorption was used to compare the two materials. The results show that micro-lattice structures made from stainless steel outperform the aluminium ones in energy absorption ability. The highest amount of absorbed energy was measured for BCCZ structure. This thesis describes the failure mechanism of micro-lattice structures and offers a complex evaluation of energy absorption for both materials.
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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.
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The developement of SLM laser strategy for lattice structure fabrication
Jaroš, Jan ; Dočekalová, Kateřina (referee) ; Vrána, Radek (advisor)
Additive technology (AT) is increasingly used to design unique parts, mainly due to the ability to produce complex structures such as lattice structures. However, this also includes the need to modify the process parameters or the production strategy of the AT, which is usually set to produce volume geometry. Using samples corresponding to the geometries of the lattice structures, the exact input values were measured, which were used to design the SLM (Selective laser melting) production process using a contour strategy. Thanks to this, vertical and angled (35.26°) struts with low porosity (up to 0.2 %), low surface roughness and high dimensional accuracy were produced. Porosity was measured on µCT, surface roughness and dimensional accuracy were measured on STL data. The results show that if the parameters of the SLM process are set correctly, it is possible to produce struts with low porosity and surface roughness using different combinations of laser power and scanning speed. The above findings were used in the creation of script that allow the selection of suitable process parameters to produce lattice structures.
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Topological optimization and lattice structures for aerospace components
Petržela, Zdeněk ; Hutař, Pavel (referee) ; Paloušek, David (advisor)
Low product weight in combination with high mechanical properties play a crucial role in reducing operating costs in the aerospace industry. For this purpose, topology optimization and lattice structures are used. Additive manufacturing processes enable the production of optimized parts with geometric complexity. So far, no clear and comprehensive approach for designing a machine part with reduced weight in this way has been presented. The aim of this work was to map the topology optimization process with the use of lattice structures, corrected by experimentally determined production limits. Furthermore, the work deals with the implementation of the proposed methodology in optimization of a real machine part, its production from AlSi10Mg metal powder using selective laser melting technology, and verification of its manufacturing accuracy and vibration response. To determine the production limits, a series of lattice strut tests were performed. According to dimensional, weight and porosity analysis of lattice struts, a minimum applicable cross-section of the strut was chosen. Struts with this cross-section were subsequently applied into the beam samples with the BCC and BCCz lattice structure. Based on the mechanical response, the BCCz lattice structure was selected for application in the optimized part. For a more accurate mechanical behaviour prediction, based on actual lattice structure response, corrected elasticity modulus and yield strength value for BCCz lattice type were determined. These parameters were applied into FEM simulation in the lattice optimization phase. After solving the problem of lattice structure geometry export from FEM software, the optimization methodology could be completely defined, the part was manufactured, and the design potential was verified.
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Design of lattice structures for additive manufacturing using Selective Laser Melting technology
Vrána, Radek ; Maňas, Pavel (referee) ; Koutný, Daniel (advisor)
Metal additive technology allows to create objects with complex shape that are very difficult to produce by conventional technologies. An example of such component is a porous structure which is composed of periodical truss cells. This diploma thesis deals with the prediction of the mechanical properties of very small lattice structures made of additive manufacturing technology Selective Laser Melting. Using the proposed test specimens it was found that real dimensions of the trusses varies with size and orientation to the base platform. It was proposed and tested samples for rod tensile test made of SLM. Based on the real information about dimensions and mechanical properties of rods were predicted mechanical properties of lattice structures. A lot of mechanical tests were carried out to obtain the real mechanical properties. Test results and conclusions are described in the thesis.
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Research on process parameters for producing of a structured material made by Selective Laser Melting technology
Richter, Vladislav ; Koutný, Daniel (referee) ; Vrána, Radek (advisor)
Selective laser melting (SLM) is one of additive technologies which allows manufacturing of components with very complex shape. One of the examples are porous lattice structures which are used in cosmonautics or medicine due to its good mechanical properties and low weight. In this work the influence of processing conditions (laser power and laser scanning speed) on material properties and geometry of as-fabricated trusses is investigated. Wide range of laser powers (100–400 W) and laser scanning speeds (1000–10000 mm/s) were used to determine optimum process parameters. Truss size, morphology and internal porosity was investigated using optical 3D scanner and X-ray micro computer tomography (mCT). Based on executed measurements optimum processing conditions were determined to be 350 W and 3000 mm/s. It is possible to manufacture faster geometrically more precise structures with equal internal porosity due to optimization.
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Costs reduction in production of Al-alloy castings
Nováková, Lucie ; Lána, Ivo (referee) ; Roučka, Jaromír (advisor)
This thesis deals with solving the most serious internal defects in castings made of aluminum alloys which are cast in sand molds in Slévárna a modelárna Nové Ransko Ltd. The problem solving contains a description of the problematic castings with the investigation of the structure and phases and subsequent detailed analysis of their production. The Author of this thesis also examines the influence of Fe and Mn on a possible formation of the internal porosity with the help of test meltings with the evaluation of the internal structural change. The Author’s design solution is a close checking of chemical composition with regard to the ratio Mn / Fe present in the alloy, the purchase of Foundry Degassing Unit to reduce gassiness of melted metals and better control of gassiness with the help of the appropriate equipment for the density Dichte index.
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The study of the effect of additive manufacturing technology parameters Selective Laser Melting properties of the produced object
Žabka, Marek ; Koukal, Ondřej (referee) ; Vrána, Radek (advisor)
Metal additive technology currently finds use in a large number of industrial sectors. Mainly in domains such as aviation, medicine and astronautics, the emphasis is laid on mechanical and material properties of materials. This bachelor thesis deals with the research study of process parameters of technology Selective Laser Melting for material AlSi10Mg and stainless steel 316L. In thesis the impact analysis of main process parameters: laser power, scanning speed, hatch distance, layer thickness, especially on the porosity of the samples was carried out. Recommended settings for both materials were found based on the research of the current state. It was further found out the influence of parameters such as powder humidity or laser scan strategy.
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Evaluation of Mechanical Properties of Lattice Structures Made by 3D Metal Printing
Pliska, Jan ; Skřivánková, Vendula (referee) ; Vrána, Radek (advisor)
Additive manufacturing technologies allow manufacturing of complex structures which are near impossible to manufacture by other more conventional technologies. A fine example of these complex structures is a periodic metallic micro-cellular structure This bachelor thesis is focused on summarization of known mechanical behaviour of lattice structures manufactured via Selective Laser Melting. This study also investigates suitable comparison criteria for lattice structures. Required values for determination of material constants were obtained from mechanical testing of real specimens. For faster evaluation of mechanical testing, automatic script in MS Excel was created. Research showed up some of the major parameters characterising the mechanical behaviours of lattice structures. It is possible to compare qualities of lattice structures based on criteria presented in this work.
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