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Design of a 3D print head for mixing additives into cement mixtures
Vícha, Daniel ; Dočkal, Aleš (referee) ; Škaroupka, David (advisor)
The subject of the thesis is the design of a 3D printing head for cement-composite mixtures (concretes). The device enables the addition of the basic component of the mixture by using a liquid solidification accelerator, followed by active homogenization of the mixture and dosing at the printing site. 3D printing of cementitious mixtures often leads to a loss of buckling stability of the printout. Therefore, it is necessary for the printed material to contain additives that accelerate the solidification of the mixture. However, these additives can cause clogging of the hoses when the mixture is pumped into the print head due to premature solidification. Hence, a more suitable solution is to mix these additives in the print head itself. The objective was to develop a 3D print head that allows for homogeneous mixing of the additives in the mixture, thereby eliminating complications associated with pumping. A working prototype of the print head was designed, which consists of a mixing and extrusion chamber. The mixing efficiency of this prototype was verified through numerical simulations using Particleworks. Subsequently, the prototype underwent a mixture experiment without a solidification accelerator to investigate pumpability through the printhead. Based on the numerical simulations, it was determined that the proposed prototype provides sufficient homogeneity of the solidification accelerator with the cement mixture, which should resolve the issues associated with pumping the accelerated mixture. By having a separate mixing chamber, the mixing efficiency can be controlled by adjusting the speed of the motor that drives the mixing shaft. The print head was designed to allow extrusion to be interrupted during print head passes. This was achieved by extruding the mixture into the open space of the chamber using a screw feeder. Therefore, based on the conducted experiments and numerical simulations, it can be concluded that the developed print head has the potential to enhance the quality of 3D printing of cement mixtures and eliminate the problems associated with pumping.
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Development of hybrid technology for the production of polymer latice structures
Florián, Vojtěch ; Maňas, Pavel (referee) ; Škaroupka, David (advisor)
This thesis deals with the development of a hybrid technology for the production of polymeric rod structures from PLA filament. The main objective of this technology is to increase the printing productivity by forming some of the rods in BCCXYZ structure without melting them completely. The first step was to conduct basic research on polymer forming. This involved a series of tests, including FEM simulations, printing of individual strut members, and analysis of morphology using X-ray powder diffraction (XRD). The results confirmed the feasibility of polymer forming, which led to further development of hybrid printing technology for BCCXYZ structures. The fabricated structures were subjected to compression loading tests and compared with the results of other printing technologies, including their production costs. In this way, the advantages of the hybrid filament rod structure printing technology were identified. To demonstrate the technology, a mould simulating a fibreglass part was created. This research contributes to the advancement of polymer structure printing and has the potential to improve the efficiency and economic viability of the process in industrial applications.
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Design of auxetic structures for the 3D print
Sobol, Vítězslav ; Škaroupka, David (referee) ; Červinek, Ondřej (advisor)
Behavior in which the material expands in one direction and in a perpendicular direction under tensile loading is called auxetic and is associated, e. g. with increased indentation resistance. Auxetic behavior is mainly due to the typical geometry of the internal structure. Therefore, it can be achieved by a unique arrangement of inner micro-lattice structure. Through additive technologies such as Selective Laser Melting (SLM), it is possible to manufacture such complex geometry. This bachelor thesis deals with the design of a spatial micro-lattice structure that will exhibit auxetic behavior and can be made by the SLM method. Based on an extensive research on the topic of 2D and 3D auxetic structures, a new type of auxetic structure was designed. The manufacturability was verified by making several samples in different dimensional configurations. Auxeticity and mechanical properties were subsequently tested using a drop test. By evaluating it, it was possible to determine the influence of dimensional parameters on the overall behavior of the structure.
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Styling of the passenger car Proton Prevé
Burjeta, Josef ; Karásek, David (referee) ; Škaroupka, David (advisor)
The thesis is focused on styling a real passenger car Proton Prevé with regard to the quality of surface modelling using computer software Autodesk Alias. The stylistic adjustments were made on basis of the background research and poll focused on the target group. Selected body parts have been modified according to the desired sport character of the car and the current vehicle’s appearance. The result of the work is a surface model, which was created using A-Class modelling methods under the direction of Evektor company. The benefit of the thesis is facelift of an existing car with consideration of the current market situation and customer requirements.
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Redesign of the chip reader
Kusyn, Martin ; Rubínová, Dana (referee) ; Škaroupka, David (advisor)
The bachelor thesis is focused on redesign of a microchip reader for 3D printer filament cartridges. The project deals with current market analysis, as well as analysis of previous cover of the device, application of basic technical and ergonomic parameters, description of proposed solution and its implementation onto current hardware. Emphasis was placed upon ergonomics of handling, reader-cartridge interaction, effective usage of internal space, positions of internal components and application of additive manufacturing guidelines for the manufacturing processes of the cover. Manufacture, fitting and testing of a prototype for the new cover for the microchip reader are also part of this project.
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Friction components produced by rapid prototyping
Pečenka, Tomáš ; Škaroupka, David (referee) ; Omasta, Milan (advisor)
The main aim of this bachelor thesis is to make an overview of use of additive technology for production of friction components. The first part is concerned on review of additive methods and type of materials. In the second section are situated applications of this technology for fabrication of friction components. The main goal of last part is research in area of tribology of parts manufactured by additive technology.
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Construction of the stand for the filaments on spools
Bezděk, Petr ; Dočkal, Kryštof (referee) ; Škaroupka, David (advisor)
The aim of this bachelor thesis is to develop a stand for filament spools with minimal unwinding resistance, which eliminates stitching of filament and calculates the amount of unwound material. The stand is designed for a spool filament in the weight range of 250 g to 2.5 kg. Furthermore, the goal is to make the stand universal and usable for various 3D printers. The problem is solved by selecting the most appropriate concept for the problem based on the applicable concept analysis. The work contains an overview of the essential facts concerning stands, unwinding and 3D printing. Subsequently, the key issues are analysed on the basis of balancing the benefits of the possible variants of the concept. The chosen concept is solved in structural parts, which ultimately form a functional unit and a completed product. The result is a complete stand design in the form of written work, production documentation and manufactured product. The stand function has been verified by testing. The work is beneficial in terms of expanding awareness of rack issues, identifying 3D printing problems associated with the spool stand, designing and finished products for use in printing. The design is entirely designed to produce only one piece.
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Design of the Vehicle for the System of Sustainable Urban Mobility
Škaroupka, David ; Kotas, Patrik (referee) ; Pelikán, František (referee) ; Zdařil, Zdeněk (referee) ; Zvonek, Miroslav (advisor)
This dissertation is a response to the negative trends in urban mobility, which led many authors to conclude on the need for a new approach to personal transport in the cities. The work has creative character, but in the conceptual level, it is taking into account the specific needs of sustainable urban mobility and build on the existing innovative transport solutions. The result of dissertation is a vehicle vision, understood as an element of urban mobility that respects the character of the zones of free movement of persons, but it is also suitable for transport over longer distances.
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Design of the portable veterinary X-ray machine
Kalenský, Ondřej ; Surman, Martin (referee) ; Škaroupka, David (advisor)
This diploma thesis is focused on the design of a product family of portable veterinary x-ray generators. The thesis deals with the possibilities of using parameterization when designing products which are part of a product series. The main body of the thesis lies in the design of a parametric script which generates variations of portable veterinary x-ray generators depending on the size and position of the inner components. The outer surfaces are defined by algorithms from the input parameters. It is possible to alter the individual attributes (e.g. the progresion of curves, the dimensions of component parts and the proportions between the individual parts). The output from the parametric script is three size-variations of the product.
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Comparison of tensile properties of polymeric samples produced by extrusion based 3D printing
Krajcar, Ivo ; Vespalec, Arnošt (referee) ; Škaroupka, David (advisor)
The subject of this work is a summary of the contemporary knowledge about 3D printing and mechanical properties of a prototype manufactured this way. Main goal is to compare the frequently used FDM method with the innovative APF method of 3D printing from the Arburg company. ASA and CPE materials were chosen for researching this method. On these materials, tensile strength was measured. Aditionally, for comparison between the two methods, referential samples manufactured by injection moulding were made. A percentual difference in strength of each sample was compared against these. 60 samples in total were made for this comparison. After evaluation of the results, it was found that in the tensile strength the samples made by the APF method are approximately 30 % less strong than the referential sample. The samples made by the FDM method are approximately of the same strength as the referential sample.
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