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Effective management of plastic waste
Kostková, Kateřina ; Pavlas, Martin (referee) ; Gregor, Jiří (advisor)
The main content of the submitted diploma thesis is the implementation of analysis of separated plastic waste and examination of the issue of extrusion tests. The practical knowledge is preceded by a search of waste management in the Czech Republic and get acquainted with the issue of polymer materials. The research is about plastic waste management and preparation of polymeric materials for extrusion tests. Theoretical knowledge is then applied in the practical implementation of extrusion tests.
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Fatigue endurance of extruded Mg alloy AZ91E
Sobola, Petr ; Štěpánek, Roman (referee) ; Pantělejev, Libor (advisor)
This thesis deals with fatigue behaviour of magnesium alloy AZ91E produced by extrusion. In the frame of this work, basic mechanical characteristics and data from performed fatigue tests were obtained. Further metallographic analysis of microstructure and fractographic analysis of broken specimens after fatigue tests were carried out.
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Experimental comparison of recycled and non-recycled filament of ABS plastic
Grygar, Filip ; Krčma, Martin (referee) ; Koutecký, Tomáš (advisor)
Plastic waste which arises from 3D print could be recycled. One of the most used materials is ABS with which this degree work deals. During recycling of ABS mechanical qualities rapidly deteriorate which is compensated by adding non-recycled ABS. This degree work dealt with a ratio of 25% of recycled to 75% of non-recycled material which is a ratio not have been tested so far, and most likely represents a boundary ratio when recycling still makes sense. Unfortunately, it was not possible to extrude from a recycled material a filament of high-quality enough which could be used for problem-free print. It was influenced by non-homogeneity of crushed components and the construction of an extruder. For improving the characteristics a more complex extruder would be needed, with a bigger screw diameter or with two screws, and also a cooling system with more zones. Professional grinders with screens would have to be used for improving homogeneity of the material. The melt flow index of the liquid alloy and the testing of the filament itself showed that this way is practicable and such a recycling is realistic.
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Properties of polyethylene blown-films dependent on their composition
Štaffová, Martina ; Poláček, Petr (referee) ; Tocháček, Jiří (advisor)
This work deals with the influence of quantity of recycled material on physical properties of blown-film. The task of this work is to prepare set of laboratory made films with amount of LLDPE granulate from 0 to 100 % with addition of LDPE recycled material and furthermore with addition of filler, calcite. The following methods were used for characterization of blown films: tensile test, differential scanning calorimetry, Fourier transform infrared spectroscopy, confocal laser scanning microscopy. The same measurements were performed also on industrial made blown-film.
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Testing of processing stability of PP-g-IA
Hampapa, Břetislav ; Tocháček, Jiří (referee) ; Kučera, František (advisor)
The Bachelor’s study is interested in processing stability of polypropylene grafting with Itaconic anhydride. A present knowledge about thermal degradation of Itaconic derivatives was summarized in theoretical part. Samples were prepared by multiple extrusions technique from virgin PP (Borsodchem, Hungary) and PP-g-IA. Die temperature 230 °C, processing time 4 minutes by 20 RPM. Qualitative and quantity analysis was made by FT-IR spectroscopy.
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Surface relief evolution in cast superalloy In738LC fatigued at room temperature
Samek, Petr ; Obrtlík, Karel (referee) ; Juliš, Martin (advisor)
Low cycle fatigue is an important valving parameter of materiale which are exposed random alternate strain during their operation. The alternate strain in that material is caused by temperature fluctuations during operation and outages such as aircraft engines. Tests of low cycle fatigue were performed on samples of superalloy Inconel 738LC at stable room temperature at 23°C. The actual experiment took place at certain intervals, consisting of cycling itself, and observing changes in surface relief by light and electron microscopy. There was observed significant surface relief at an early stage of low cycle fatigue. We compared results of measurement with other different observation methods.
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Experimental comparison of filament produced from recycled and regular PET
Tomčová, Renata ; Vaverka, Ondřej (referee) ; Koutecký, Tomáš (advisor)
This bachelor thesis deals with the experimental comparison of filament made from recycled and common PET. Filament was made from commercial granulate of PET, PET-G and from recycled PET bottles. Sample pieces were printed using FDM technology from these filaments and then the sample pieces were tested using a tensile test. The sample pieces made from recycled PET filament had one third worse tensile strength than the sample pieces made from common PET and PET-G filaments. Thanks to this bachelor thesis it is possible to decide, if it is worthy producing filament from recycled PET bottles even at the cost of reducing the mechanical properties of final products.
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Evaluation of dimensional and shape accuracy of components made of plastic
Tuza, Marek ; Dobrocký, David (referee) ; Sedlák, Josef (advisor)
The aim of this thesis is to evaluate the dimensional and shape accuracy of components made of plastic. A total of 10 samples, produced by two types of production, extrusion and 3D printing using the FFF method, were used for this purpose. The semi-finished products were milled after production, which resulted in samples of the required dimensions. The samples were milled on one side without cooling emulsion and on the other side with cooling emulsion, which significantly affected the resulting shape accuracy values. Thus, a total of 20 surfaces were evaluated. Two parameters were selected to evaluate the dimensions, namely distance and parallelism. When measuring the shapes, 11 parameters were evaluated using a 2D roughness profile and a 3D surface texture. One of the most used parameters that was evaluated when measuring shapes was the arithmetic mean deviation of the roughness profile, which is denoted as Ra. The research found that the highest accuracies were measured for the material PA produced by 3D printing and milled with a cooling emulsion. At the end of the practical part, the author also makes recommendations regarding the practical use of materials.
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Design of screw extruder for robotic 3D printing from pellets
Machač, Radim ; Škaroupka, David (referee) ; Křivohlavý, Petr (advisor)
The goal of this bachelor thesis was to design a screw extruder suitable for 3D printing, which will be able to process cheap plastic pellets instead of filament. The first part of the work is devoted to the extruder components, the extrusion process and the use of this polymer processing technology in the design of a screw extruder for 3D printing. An extruder model is created with regard to minimum dimensions and weight. During the design, requirements were set for ease of maintenance. The result is an extruder that enables both large-volume and small-volume printing, which, according to the calculations, is equal to the printing speed of ordinary 3D printers. This work will serve in the area of the usability of cheap plastic pellets as an input material for 3D printing. With its content, it also contributes to the development of screw extruder designs suitable for use in laboratories or industry.
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