National Repository of Grey Literature 14 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Analysis of different ways/speed of cooling Al casings during their solidification and influence to the mechanical properties, structure and dendrite arm spacing of the final castings
Holčapek, Jiří ; Vašťák, Patrik (referee) ; Horáček, Milan (advisor)
This master´s thesis deals with finding the best way to cool a ceramic shell mould during solidification of the melt to achieve the requiered values of mechanical propeties. During the experimental part we tried different cooling methods. This involved blowing the shell with compressed air, submerge in water and wetting in a quenching polymer solutions at different speeds. The best way reaching the highest values of machanical properties was chosen the method of rapid submerge of the shell mould in a solution of quenching polymer of a specific concentration. The mechanical properties have been achieved.
Influence of location of Al castings in a heat treatment furnace on mechanical properties
Toufar, Tomáš ; Vašťák, Patrik (referee) ; Horenský, Jiří (advisor)
The present Master thesis deals with location of aluminium castings in the heat treatment furnace and its influence on mechanical properties. As testing samples for the experimental part, tensile bars were used; they were cast from the subeutetic silumin AlSi7Mg0,6. These samples were placed in the furnace in the locations where temperatures were calibrated by the furnace supplier. Then, tensile tests were performed to evaluate the resulting mechanical properties of the samples. The experiment was carried out in the foundry of non-ferrous metals, MESIT foundry Ltd., Uherské Hradiště.
Influence of degassing parameters on quality of Al castings
Jeřábek, Petr ; Horenský, Jiří (referee) ; Vašťák, Patrik (advisor)
This master’s thesis is focused on optimalization of degassing parameters in the foundry plant and effect of these parameters on mechanical properties of Al-Si alloys. In practical part is used factorial experiment to research effect of degassing parameters on mechanical properties and dichte index. After optimalization the new process is validated by comparing with the previous one. This experiment was taken on AlSi7Mg0,6 alloy in foundry plant MESIT foundry, a.s.
Influence of raw materials to the final quality of aluminium investment castings
Macko, Martin ; Vašťák, Patrik (referee) ; Horáček, Milan (advisor)
The purpose of this thesis is to assess the current state of production of ceramic shells in MESIT Foundry, a.s. and optimize it. The shells are evaluated in terms of their bending strength, gas permeability and microstructure. Subsequently, castings produced using the shells are evaluated with regard to number of non-conforming products and presence of defects. The final part seeks to compare different shells and outlines a possible new approach to the development of ceramic shells.
Present state of investment casting technology
Ostrézí, Barbora ; Vašťák, Patrik (referee) ; Horáček, Milan (advisor)
This bachelor thesis is focusing on production of lost wax pattern and monitoring of the latest trends in this area. Thesis describes procedures of production from mother die, types of used waxes, production of ceramic shell, de-waxing and shell firing, production and using ceramic cores, removal of ceramic shell and finishing operations. The goal of this thesis is to formulate literature search dedicated to overview of presently used technologies and also the latest raw materials used in this technology.
Foundry technologies from the point of view of castings accuracy
Hýbal, Ondřej ; Vašťák, Patrik (referee) ; Horáček, Milan (advisor)
This bachelor’s thesis deals with various casting technologies, specifically about investment casting technology, evaporative-pattern casting and die casting. These technologies compares not only on achieving the smallest dimensional tolerances of the final casts, but also of other factors such as surface roughness, wall thickness and production economics. This thesis also describes casting accuracy in general and informs about the management strategy of Six Sigma.
Optimization of wax pattern technology in the company Fimes
Žuja, Jaroslav ; Vašťák, Patrik (referee) ; Horáček, Milan (advisor)
This thesis is to evaluate currently used wax and compare its properties with of newly purchased one. Further, it is to evaluate whether the quality is reflected by using "boiled wax'', which is being used as a runner wax. All tests were carried out at the Fimes a. s. In the first part of this thesis, there is a brief description of the lost wax method. This is followed by a decription of wax blends from technology point of view. The experimental part describes the operations from the production of wax patterns, through their dimensional inspection, up until dewaxing process. All the results are noted and compared.
Optimization of wax and ceramic shell technologies in the company Fimes
Kolesár, Roman ; Vašťák, Patrik (referee) ; Horáček, Milan (advisor)
The thesis continue thematically in the previous development of the wax mixtures for the company Fimes. The general description of the investment casting process from the production of the die to casting of the wax pattern is handled in the first part. It is followed by the summary of the previously carried out experiments on cracking the shells. The experimental part describes the individual operations from the production of tested wax patterns to casting in the Boilercláv. The newly developed wax mixture is compared to the wax mixture used by the company Fimes. The experiments focus on the possibility of cracking the shells during the casting process and the dimensional stability of wax mixtures.
Optimized ceramic shell for manufacturing of aluminium castings by using lost wax technology
Mazůrek, Tomáš ; Vašťák, Patrik (referee) ; Horáček, Milan (advisor)
This diploma thesis deals with the possibilities of optimization of ceramic shell molds in the method of investment casting. In the first part is mentioned a complete technological process of the method with focusing on production and quality control of the ceramic shell and components, from which it is produced. The experimental part is divided into two parts, in the first are results of laboratory tests, which were tested both the current ceramic shell and shells which have been considered as a possible replacement. In the second section were verified conclusions of the experimental findings and recommendations of the laboratory results in pilot plant conditions.
Optimizing the technology of Al casting manufactured by the "lost wax process"
Mikulka, Vít ; Vašťák, Patrik (referee) ; Horáček, Milan (advisor)
This diploma theses deals with possibilities of using numerical simulation for optimizing production of highly demanding thin-section casting produced by investment casting process. The casting made of aluminium alloy in which the manufacturing process was very problematic (occurrence of macro and micro shrinkages) has been chosen. By numerical simulation the existing technology has been analysed and based on this the possible reasons for defects found. This was later confirmed also by metallographic examinations. Following to this several options for a new technology were proposed and again by simulation checked their suitability. By comparing all above mentioned options two versions have been chosen in the end which was later tested in production with satisfactory results.

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