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Optimization of diecasting process of an electric motor bear shield casting
Krňávek, Štěpán ; Kolmačka, Marek (referee) ; Roučka, Jaromír (advisor)
The present bachelor thesis deals with optimization of a die casting technology used to make a casting of an electric motor bear shield which is cast in the Siemens Elektromotory Ltd. foundry in the town of Mohelnice. There are foundry defects in the casting which are undesirable and must be removed. The introduction of the thesis is devoted to an analysis of the bear shield casting, its casting parameters, an alloy AlSi9Cu3(Fe) used and to problems resulting from the occurrence of defects in the casting. Subsequently, the die casting technology is explained, machines used in this technology and their new structural design are described, and the most frequently occurring defects in this technology and their causes are mentioned. In the following part of the thesis an x-ray analysis of the casting, a thermal analysis of the casting and a microscopic analysis of the defect cavity are carried out. On the basis of the analysis the casting defects have been identified as closed air - gas holes. To minimise the occurrence of the given casting defects several possible corrective measures have been suggested.
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Influence of exothermic sleaves on solidification of aluminium alloys
Zajíček, Roman ; Krutiš, Vladimír (referee) ; Roučka, Jaromír (advisor)
The master’s thesis deals with the influence of the exothermic risers on the solidification of aluminum alloys. The work is divided into three parts. The first theoretical part describes the differences of properties of cast aluminum alloys compared to other based metals, especially iron alloys. It also describes the methodology of designing risers, composition of exothermic mixtures and finally gives an overview on the simulation programs on the market, their application in foundry practice and briefly explains how to define the material in the simulation program ProCAST. The second part describes the experimental measurement of the solidification time of aluminum alloy AlSi7Mg0,3 in the sand form with exothermic riser. The final section describes the simulation of experimental measurements. Further with help of simulation software it is tried to find the general principles that have an influence on feed module rate of exothermic riser.
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Interaction Core - Melt by Casting of Cylinder Heads from Al Alloys in Semi-Permanent Moulds
Hlavsa, Petr ; Roučka, Jaromír (referee) ; Tegel, Michal (referee) ; Rusín, Karel (advisor)
This dissertation thesis deals with interactions on the interface core - melt by casting of cylinder heads from Al alloys in semi-permanent moulds and solves a specific problem with sticky sand after decoring of a diesel cylinder head casting. It describes in detail the process of core production using the Cold-Box method and process of casting using the progressive technology Rotacast. It theoretically analyses the reaction on the interface core-melt and presents a classification of surface defects by Al castings produced by gravity casting into semi-permanent moulds. It also states the results of technological tests of binders, core mixtures and cores (Cogas analysis). By solution of a problem with sticky sand in intake and exhaust ports of diesel cylinder head casting is used methodology for problem solving DMAIC. All experimental tests are solved in laboratory and production conditions of an international company dealing with casting of cylinder heads from Al alloys in semi-permanent moulds.
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Influence of ceramic filtrers on metal streaming in running systems
Vymyslický, Jakub ; Láník, Boris (referee) ; Roučka, Jaromír (advisor)
This thesis deals with influence of ceramic filters on metal streaming in running systems. The purpose of this thesis is to investigate the influence of porosity, thickness of ceramic filters and also viscocity of molten metal on mold filling. Hydraulic resistance of ceramic filters and possibility of its use in numeric simulation is also tested. At the beginning of the thesis there is theoretic analysis of filtration which inlcudes inclusions in cast irons, filtration matters, gatting systems design, hydraulic resistance and numeric simulation. The second experimental part of this thesis is focused on measuring shedding of molten grey cast iron and ductile iron through gatting systems with filters which are labelled VUKOPOR S. The experimental part then deals with evaluation of experiments results, calculation of hydraulic resistance and numeric simulation with the use of measured data.
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Technology of high pressure die-castings and influences having effect on their quality
Štipl, Pavel ; Prášil, Tomáš (referee) ; Roučka, Jaromír (advisor)
This diploma thesis deals with the technology of high pressure die casting and especially influences having effect on their final quality. The aim of this thesis is to design the measures to convert casting of the cylinder for chainsaw into the serial production. The thesis contains a description of the production of castings by technology of high pressure die casting, theoretical analysis of the factors with effects on their final quality and practical description of the conversion casting of cylinder for chainsaw into the serial production. The problem of converting to serial production has been solved by several samplings and final test series. Part of each sampling is analysis of defects and design of measures leading to elimination or at least minimization of such defects. On the basis of the production process has been successfully optimized and casting of the cylinder for chainsaw was successfully converted into the serial production. The results of this work also allowed for a smooth conversion into the serial production of another type of cylinder, manufactured by company MOTOR JIKOV.
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Manufacturing of aluminium alloy castings in sand mould
Exner, Zbyněk ; Roučka, Jaromír (referee) ; Záděra, Antonín (advisor)
The thesis theoretically deals with research activities in the field of molding mixtures, description and division of aluminum alloys for castings. Furthermore, the thesis presents the process of production of the cylinder head of the internal combustion engine Jawa 50, from the design of a 3D model and its production by 3D printing to its casting from aluminum alloy EN AC-46000. Molds from bentonite, self-hardening and oil-bentonite molding mixtures were used to cast the test casting. To complement the experiment, the casting was also made using the lost-wax casting method. For the production of wax models, it was necessary to make a mother mold. Subsequently, two different ceramic shells were made. The first one was designed to cast only one casting, the second one, with a different orientation of the models to the inlet, allowing to cast two pieces of castings at once.
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Prediction of mechanical properties of iron castings by means of numerical simulation
Filipek, Szymon ; Kotas, Petr (referee) ; Roučka, Jaromír (advisor)
The aim of this thesis was to design optimization of the amount of alloying elements (copper and molybdenum) in liquid alloy, which improve mechanical properties of the grey cast iron. An adjustment was made to exceed requirement for a minimum strength in the stressed area. The strength limit was exceeded by approximately 60 MPa. Foundry simulation software MAGMAsoft was used for theoretical optimization. Conformity between the mechanical properties evaluated by simulation and the measured values of hardness, tensile strength was confirmed in the first step of the experimental part. A draft of optimization was created in the second step, which led to savings of the alloying costs.
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Application of magnesium alloys castings
Pernica, Vítězslav ; Liškutín, Petr (referee) ; Roučka, Jaromír (advisor)
Magnesium alloys are still idle in technical applications because of their properties. The history of metal is not very old, the first application of its alloy started on the beginning of the 20th century. Magnesium is very light. Its weight is about one third less than the weight of aluminum and it is the third most frequented structural metal. However its preparation and processing can be problematical because magnesium has high affinity to oxygen. It causes intensive burning. During the century of stature have been improved both production and alloys. The usage of magnesium alloys took more importance and it is the most used alloy in automotive field sofar. Recently its demand expands mainly in electrotechnics. Next usage we can find in aeronautics, energetics, military and many other branches.
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Heat treatment of aluminum casting alloys
Holátko, Petr ; Roučka, Jaromír (referee) ; Kaňa, Václav (advisor)
This bechelor thesis deals with the description of the heat treatment of aluminium casting alloys and is particularly focused on the frequent heat treatment, which is hardening. The first part describes the properties of aluminium alloys and are further explained the different kinds of heat treatment. The second part describes the experiment, which were cured, two different aluminium alloys. Here, the work focuses on change in hardness before and after hardening.
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The influence of cast iron inoculation with bizmut containing inoculant on structure and mechanical properties
Nyékyová, Dominika ; Navrátil, František (referee) ; Roučka, Jaromír (advisor)
The diploma thesis deals with the modification and inoculation of cast iron with spheroidal graphite, the influence of the chemical composition on the shape and size of the graphite nodules and ferrite/perlite ratio in the structure. The aim of the practical part was to determine the effect of inoculant containing bismuth (SMW 605) on microstructure and mechanical properties of ferritic ductile cast iron GJS 400-15. The dissolving time of mold inoculant was further investigated. The samples were subjected to a tensile test, Charpy impact test, hardness test and graphite morphology and ferrite/perlite examination using standard ČSN EN ISO 945-1.
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