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Development of process parameters for Selective Laser Melting technology for processing of aluminum alloy AlSi7
Zvoníček, Josef ; Dočekalová, Kateřina (referee) ; Koutný, Daniel (advisor)
The diploma thesis deals with the study of the influence of process parameters of AlSi7Mg0.6 aluminum alloy processing using the additive technology Selective Laser Melting. The main objective is to clarify the influence of the individual process parameters on the resulting porosity of the material and its mechanical properties. The thesis deals with the current state of aluminum alloy processing in this way. The actual material research of the work is carried out in successive experiments from the welding test to the volume test with subsequent verification of the mechanical properties of the material. Material evaluation in the whole work is material porosity, stability of individual welds, hardness of the material and its mechanical properties. The results are compared with the literature.
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Processing of Inconel 939 alloy using laser powder bed fusion at elevated temperatures
Hertl, David ; Dočekalová, Kateřina (referee) ; Malý, Martin (advisor)
The thesis deals with the problem of Inconel 939 alloy processing by SLM technology using base plate preheating. The main objective of the work is to verify the effect of base plate preheating on residual stresses. The problem was solved by two approaches: process simulation, and subsequent experimental verification. The process simulation with preheating temperature of 400 °C achieved the highest agreement with the experiment with a deviation of 4.1 %. Based on the experiment, a suitable base plate preheating temperature of 100 °C was determined to reduce the deformation and residual stresses. By processing Inconel 939 using preheating temperatures of 100 °C and 400 °C, static mechanical properties comparable to those of the standard components processed by SLM technology from Inconel 939 after the heat treatment were achieved. These results offer the potential for significant reductions in overall production time and costs associated with manufacturing Inconel 939.
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Design of additively manufactured oil-water heat exchanger for formula student
Březina, Josef ; Dočekalová, Kateřina (referee) ; Koutný, Daniel (advisor)
Diploma thesis deals with a design and manufacture of oil cooler by technology Selective Laser Melting for Formula Student. The main goal of the design is to ensure optimal oil circuit cooling at a minimal mass. The design of manufactured oil cooler is based on a plate heat exchanger concept with optimized intakes by CFD simulations and heat exchange body with fins of thickness 0.17 mm. An analytical model was created. SLM process parameters were optimized for a thin walls printing, Subsequently, a fabrication of testing parts was finished for measuring pressure drops and performances of micro heat exchangers. Results were used for an accuracy improvement of the analytical model and for consequent optimization of heat exchange surface. Afterwards optimization was executed for inlets and outlets by using flow simulations. A prototype was built and verified on a test stand. Performance of the designed oil cooler is 4.5 kW for race mode, where temperature drop of oil circuit is 22 °C. The lightweight design weighs 320 g, which reduces more than 47 % of a current oil-air cooler weight. Furthermore, a centre of gravity is decreased by designed placement of the cooler.
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Development of SLM process parameters for thin-walled nickel superalloy components
Kafka, Richard ; Dočekalová, Kateřina (referee) ; Koutný, Daniel (advisor)
The diploma thesis deals with the development of process parameters of SLM technology for the material IN718. The main goal is an experimental development of a set of parameters for the production of thin-walled parts with regard to material density, surface roughness and tightness. The essence of the development of parameters is an experimental explanation of the influence of laser power and scanning speed on the morphology of single tracks, which are used for the production of a thin wall. Together with walls of larger widths and volume samples, it is possible to create an intersection of parameters by which is possible to create components formed by a combination of thin-walled and volume geometry. The performed research created a material set, where the parameters of thin walls are used for the area of contours of bulk samples. We managed to produce a wall with an average width of 0.15 mm and roughness of 6 m, which meets the requirement for the tightness. The meander scanning pattern achieved a relative material density of 99.92%, which is more than with the supplier's parameters. Based on the acquired knowledge, it was possible to apply a set of parameters to components combining both geometries.
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SLM process parameters optimization for processing of AW2618 aluminum alloy
Těšický, Lukáš ; Dočekalová, Kateřina (referee) ; Koutný, Daniel (advisor)
The diploma thesis deals with possibilities for processing aluminium alloy EN AW 2618 using Selective laser melting (SLM). The theoretical part contains basic knowledge about production by this technology and possibilities of evaluation of relative density of samples. It also contains an overview of the current state of knowledge about the processing of aluminium alloys by SLM technology. Above all, aluminium alloys of the series 2000, where the main alloying element is copper. In the experimental part testing samples were designed based on the research. These samples can be divided into three areas: single-track specimens, volume samples and samples for tensile testing. Single-track and volume samples were used to find appropriate processing parameters to achieve a relative density close to full volume of material. For this purpose, the effect of the different scanning strategies on the relative density of the sample were examined. The limiting factor has been the occurrence of small cracks in the broad range of parameters studied. Mechanical properties of samples produced by SLM were compared with extruded material. It was found that the material processed by SLM achieves only half the yield strength and tensile strength of extruded material. This is mainly due to the occurrence of small cracks and other defects in the structure of the material.
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Development of process parameters of Selective laser melting technology for the production of thin-walled iron parts
Šreibr, Vít ; Dočekalová, Kateřina (referee) ; Paloušek, David (advisor)
The thesis deals with the processing of pure iron by Selective laser melting technology as a material with good electromagnetic properties. The main area is the optimization of the production of thin-walled samples, which monitor the influence of process parameters on the thickness and quality of the wall surfaces. In addition to the perpendicular walls, walls built at an angle of 45° are also examined. Another phase of the thesis is the determination of process parameters for bulk bodies to achieve the lowest porosity and high surface quality. An important part of the research is the application of acquired knowledge in the production of samples designed to test magnetic properties as well as part for a specific application. These considerations concern not only the setting of the printing parameters, but also the heat treatment and its influence on the magnetic and mechanical properties of the material. Mechanical properties were determined by tensile tests and hardness tests. All samples were made on a SLM 280HL using a 400W ytterbium laser.
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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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Analysis of thermal behavior focused on additive manufacturing of lattice structures from AlSi10Mg
Nosek, Jakub ; Dočekalová, Kateřina (referee) ; Paloušek, David (advisor)
Using Additive manufacturing it is possible to manufacture complicated components, that cannot be manufactured using conventional methods. The typical example is the lattice structure. Fabrication of these structures is complicated, and it is different from the fabrication of bulk parts. Using numerical simulation which can reflect process parameters it is possible to analyze the thermal behaviour of vertical and inclined struts fabrication. Results show that the diameter of struts influences weld track width. This influence is caused by preheating the powder material by previous scanning paths. The final geometry of inclined struts is made in more scanning layers. In this work influence of the start and endpoint of trajectory is described.
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The development of multimaterial 3D printing of metal parts by SLM technology
Pliska, Jan ; Dočekalová, Kateřina (referee) ; Koutný, Daniel (advisor)
This thesis deals with research and optimization of process parameters and methodology of production of multimaterial parts manufactured by SLM. This work investigates iron-based and copper-based materials. The aim of the work is to create a good-quality horizontal and vertical multimaterial interface. In the case of the horizontal interface, the optimal process parameters for the processing of selected materials, their subsequent optimization for a goodquality horizontal interface and verification of mechanical properties were experimentally determined. For the vertical interface, it was necessary to design a production methodology and further optimize the process parameters. Finally, some mechanical properties of the interface were determined. However, research of the vertical interface has been a scientific task with some degree of uncertainty, and as this area has not yet been fully explored, it has proved to be a more complex problem than previously thought. It was therefore not possible to completely clarify it in the given time and with the available means. This work provides a detailed description of the mechanisms of creating both types of interfaces and their properties and can serve as a basis for further study of multimaterial 3D printing of metals based on iron and copper.
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