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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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Kinematic analysis of movement of cyclist with transtibial prosthesis.
Stoklásek, Pavel ; Mazůrek, Ivan (referee) ; Paloušek, David (advisor)
This work is aiming to the area of biomechanics and deals with the experimental finding of appropriate kinematic ratios of crank mechanism on racing bicycle and transtibial prosthesis of racing cyclists with an assessment of kinematic ratios depending on the overall athletic performance. The primary aim of the work is investigation of the impact of inappropriate existing kinematic ratios of leg prosthesis and crank mechanism on the kinematics and dynamics of top athlete. The work presents experiments that proposes find out appropriate kinematic ratio of the length of kinematic members and possibility to improve overall athletic performance. The measurement is supplemented about cycling analysis of racer realized via cameras tracking system and measuring muscle activity by EMG. The work also includes a description of impact of various factors on cycling.
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Mechanical design of 3D printers for large-sized parts
Březina, Josef ; Koutecký, Tomáš (referee) ; Paloušek, David (advisor)
This thesis deals with a construction of a largescale 3D printer. The main goal of the thesis is design and manufacture of functional prototype of FDM 3D printer with a size of building chamber (520 x 520 x 480) mm. Designed printer belongs to the RepRap project. A built of the 3D printer is enclosed with a heated bed. This allows printing from PLA, PET-G and particularly ABS. In the thesis, a research was conducted into 3D printing methods from polymers, materials, printing parameters and technologies of FDM printers. The analysis was carried out in the second chapter, where knowledges from the research were evaluated and determined significant parameters of a printing quality. Final technologies were chosen on the grounds of drafts from previous chapter. The realization of the printer including strength calculations is described in a part of a construction solution. The last section of the thesis deals with a calibration of the printer.
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Surface finishing of plastic parts
Nguyen, Manh Thanh ; Škaroupka, David (referee) ; Paloušek, David (advisor)
The main topic of this barchelor thesis is surface finishing of plastic part manufactured by FDM technology. The thesis includes experimetal part which aim is to test various possibilities of surface finishing by acetone vapour etching. Two different samples of ABS materiál will be used for testing. Changes of dimension and geometry will be observed.
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Realization of the plastic holder of the car navigation
Pavlík, Ondřej ; Nohál, Libor (referee) ; Paloušek, David (advisor)
The goal of this bachelor´s thesis is suggestion and manufacture of the plastic holder of the car navigation. The literature retrieval part contains gathering of information about external holders of the car navigations and description of prototype manufacturing method. The construction part is an accompanying report of suggestion and manufacturing of the car holder. 3D CAD Model is created in parametric modeller via Autodesk Inventor Professional 2010. The holder is then made via Rapid Prototyping FDM technology.
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Mechanical design of rotary satellite antenna polarization system
Vítek, Petr ; Mazal, Pavel (referee) ; Paloušek, David (advisor)
The aim of this bachelor thesis is mechanical design of rotary satellite antenna polarization system. It is a part of a mobile satellite antenna positioned on the roof rack of a passenger car. Device must be designed to achieve precise positioning and smooth running. It must also resist moisture and temperature fluctuations. For this application, there has been selected and developed solution with toothed belt. The thesis includes a selection algorithm of drive, belt and bearings. The achieved polarization angle is 180 °. The results of this paper can be used to produce a functional mobile satellite antenna polarization.
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Mechanical upper limb prosthesis
Koukal, Ondřej ; Čížek, Petr (referee) ; Paloušek, David (advisor)
This thesis elaborates on design and fabrication of an artificial mechanical upper limb prototype for transradial amputations, i. e. for patients with stump between elbow and wrist joints. The artificial limb is designed for use in a wide spectrum of patients. Therefore, the main components are designed to be applicable to smaller as well as larger hand dimensions. The artificial mechanical limb is designed to be controlled by the other hand of a patient and enables grasping of objects via cylindrical and hook grip. Fingers are driven by tension springs and can be locked in extension. Clenching can be initiated by pressing a button, which unlocks the fingers, thus an object can be grasped. Wrist joint is adjustable when pressed a release button. Forearm joint is locked by preloaded spring. The lock of the forearm joint is released by sufficient torque. New position of the forearm joint is locked automatically when the torque is not being applied. Prototypes of the artificial mechanical upper limb were manufactured by using of rapid prototyping technologies (FDM, SLM) as well as CNC milling machine. All parts of the artificial limb were designed with regard to manufacturability by conventional methods such as casting, injection and the like. The artificial limb prototype had been designed on 3D data basis of a specific patient, who already has tested the prototype. Following materials were used on the prototype: ABS plastic, SikaBlock M940 polyurethane, aluminium and 316L stainless steel.
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Mechanical design of stend for lower limbs prostheses dynamic testing
Taufer, Tomáš ; Robenek, Dětřich (referee) ; Paloušek, David (advisor)
This work describes design and realization of testing device for dynamic tests of foot prosthesis, made by methods of Rapid prototyping. Primary objective of design is to imitate the load on prosthesis during human gait. This task is accomplished by swing motion of prosthesis inside the frame of device during the loading of heel and tiptoe. Loading components can be removed and changed so the device can be used for different measurement like walking on an inclined plane. The result of this work is fully functional device including control program with many options to control the test. The result of test is to decide whether the foot prosthesis withstands the set of cyclic loads. The area of development of prosthesis by additive methods is young for the time being. It stands out especially with different materials, design, structure of prosthesis and fast process of production. Therefore this device can be used for testing of fatigue life of prosthesis made by additive methods.
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Large-Scale Robotic 3D Printing of Polymer Composites
Krčma, Martin ; Fritschi, Ena Lloret (referee) ; Naboni, Roberto (referee) ; Paloušek, David (advisor)
Tato disertační práce se zabývá vývojem a výzkumem 3D tiskové metody pro velkorozměrový 3D tisk komplexních, funkčních objektů z recyklovaného polymerního kompozitu. První část práce je materiálově zaměřená, zabývá se složením kompozitu, procesními parametry, materiálovými vlastnostmi a degradací během 3D tisku. Výsledkem této části je publikace v indexovaném časopise, která srovnává materiálové vlastnosti a porozitu tištěných a litých vzorků. V průběhu práce jsou definovány problémy s 3D tiskem tohoto materiálu a je navrženo jejich řešení pomocí tiskových strategií. Druhá část disertační práce se zaměřuje na návrh, provedení a vyhodnocení těchto strategií. Na toto téma byly publikovány dva články, první zaměřený na aplikaci a porovnání víceosých 3D tiskových strategií a druhý, ve kterém je popsána nová metoda 3D tisku. Byly srovnány 4 metody, kombinující neplanární slicing a orientovaný 3D tisk, z pohledu kvality povrchu, obtížnosti zpracování a vystavitelnosti. Získané poznatky byly využity při návrhu zmíněné nové metody 3D tisku, založené na principu variace výšky vrstvy v kombinaci s reorientací tiskové hlavy pro zlepšení možností velkorozměrového 3D tisku objektů s jedním perimetrem, u kterých metoda umožnuje vystavitelnost převisů přes 80°.
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Processing of the Magnesium Alloys by Selective Laser Melting Method
Suchý, Jan ; Hort, Norbert (referee) ; Warchomicka, Fernando (referee) ; Paloušek, David (advisor)
Tématem předložené disertační práce je zpracování hořčíkových slitin technologií selektivního laserového tavení. Práce podrobněji rozpracovává otázku korozní odolnosti takto vyrobeného materiálu, relativní hustoty a mechanických vlastností s důrazem na použití v biomedicínských aplikacích. Hlavním cílem práce je objasnění vlivu procesních a technologických parametrů na korozní rychlost zpracovaného materiálu. V první fázi práce byla na sériích liniových a objemových vzorků zkoumána relativní hustota vzorků spolu s vnitřní mikrostrukturou a mechanickými vlastnostmi. Druhá fáze se zabývala vlivem mikrostruktury a jakosti povrchu na výslednou korozní rychlost materiálu v simulovaném prostředí lidského těla. Díky tomu se podařilo stanovit korozní rychlost SLM zpracovaného materiálu a určit, jakým způsobem ji lze měnit změnou procesních parametrů. V práci se podařilo opakovaně dosáhnout relativní hustoty materiálu 99.5 % s tvrdostí 85±6 HV, pevností v tlaku 416±40 MPa a tříbodovém ohybu 212±9 MPa, což jsou hodnoty poměrně blízké lidským kostem. Zároveň se podařilo snížit rychlost koroze materiálu o takřka 22 % snížením drsnosti povrchu z původních Ra 57.3 na Ra 34.2. V práci však nebyl zmapován detailní vliv katodických fází během korozního testu. Uvedená práce podává čtenáři ucelený přehled o problematice 3D tisku hořčíkových slitin spolu s detailním popisem vlivu procesních a technologických parametrů na proces výroby slitiny WE43. Práce definuje korozní vlastnosti 3D tištěného materiálu s relativní hustotou 99.5 % s různými jakostmi povrchu. Výsledky práce posouvají dále poznání v oblasti biodegradabilních implantátů pro využití v medicínském prostředí.
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