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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Návrh robotického pracoviště pro obsluhu vstřikovacích lisů s následnou montáží a kontrolou / Design of a robotic workplace for the operation of injection molding machines with subsequent assembly and inspection

Musil, Marek January 2018 (has links)
The thesis deals with the design of a robotic workplace for the operation of injection moulding machines. It is concerned with the design of the workplace component deployment and the evaluation of the best variant using a multi-criteria assessment. In detail, attention is paid to the end effectors of industrial robots and the assembly workplace, where finishing operations take place. Finally, the risk analysis and technical and economic evaluation of the proposed workplace are carried out.
182

Technologie výroby uhlíkových kompozitů lisováním za tepla / Technology of manufacturing of carbon fibre composites by hot forming

Přikryl, Pavel January 2019 (has links)
This master’s thesis deals with the composite materials and especially aims on the carbon and glass fiber composites. It points out different composition types and manufacturing methods which reflect in the different mechanical properties, final quality of the manufactured part and also in the manufacturing time. The practical part includes two particular manufacturing methods using prepregs, one cured in an autoclave and one by hot compression moulding.
183

Výroba rohové krytky / Production of corner cover

Hrdina, Vojtěch January 2020 (has links)
The project elaborated design of injection mould for production of corner cover, which serves to protect a reprobox from mechanical damage. The production possibilities were considered at the beginning. The injection molding technology was chosen from available technologies. The first part of the thesis is theoretic, plastics and injection molding are investigated. The choice of suitable polymer and the entire draft of mold is in the second part of thesis. The final mold is two-cavity with cold runner system. The technical and economic assessment of the proposal is carried out in the last part of thesis.
184

Advanced Proportional Servo Valve Control with Customized Control Code using White Space

Lauer, Peter January 2016 (has links)
An industrial control valve has been designed by Eaton (AxisPro® valve). The servo performance valve has onboard electronics that features external and internal sensor interfaces, advanced control modes and network capability. Advanced control modes are implement in the valves firmware. With the help of the white space it is possilbe to execute custom code directly on the valve that interact with these controls. Small OEM applications, like rubber moulding machines, benefit from the comination of build in controls and custom code, to provide adaptations for their special machines.
185

Energy Efficient Composites for Automotive Industry.

Rojas, Mariana January 2021 (has links)
Hybrid composites play a key role in sustainable development. For many years, carbon fibres in an epoxy matrix have been an attractive option for many structural applications because of their higher specific mechanical properties mostly. However, recycling and sustainability are some of the composite shortcomings; and in that context, natural fibres have gained popularity.  The present study aimed to design and manufacture short carbon/flax hybrid composites. Two different arrangements were chosen: random and layers configuration. Resin Transfer Moulding (RTM) was used to fabricate these hybrid composites. Mechanical tests and optical microscopy technique were conducted to understand the effect of the interaction of these two different reinforcements. Mechanical tests showed a remarkable difference between the hybrid configurations under flexural loadings. Furthermore, outstanding property values were observed in the hybrid configurations compared to single fibre composites. The resultant materials have seemed an attractive combination of fibres with a remarkable balance between mechanical performance and eco-friendliness.
186

Développement d'un matériau de liner pour réservoir cryogénique de lanceur / Development of a thermoplastic material for liner of cryogenic fluid storage tank

L'Intermy, Julien 17 December 2013 (has links)
Le développement de structures de plus en plus légères et présentant des rapports performances/coût toujours plus élevés est un enjeu permanent dans le domaine des transports. Les matériaux polymères présentent des caractéristiques particulièrement bien adaptées à ces besoins. Ce travail de thèse repose sur le développement d’un matériau polymère destiné à être utilisé en tant que liner de réservoir de stockage d’oxygène liquide (LOX). L’objectif est de démontrer une réduction des masses de l’ordre de 20 à 30%, en comparaison avec des structures métalliques. Pour les besoins de l’application, le matériau à développer se doit de présenter une bonne compatibilité au LOX, une faible perméabilité aux gaz, des propriétés mécaniques suffisamment élevées à basse température ainsi qu’une bonne aptitude à la mise en forme par rotomoulage. La première partie de ces travaux a porté sur la compatibilité au LOX des polymères. En tenant compte des théories proposées dans la littérature, des nanocomposites à matrice polyamide 6 (PA6) ont été élaborés et caractérisés afin d’atteindre les performances recherchées. L’influence de différents paramètres supposés régir la tenue à l’oxygène liquide des matériaux polymères a ensuite été déterminée. Les nanocomposites obtenus présentent globalement une bonne compatibilité avec le LOX. Cette étude a également permis de mettre en évidence que les résultats sont fortement dépendants des paramètres liés à l’échantillonnage. Dans un second temps, la processabilité par rotomoulage de ces nanocomposites PA6 a été évaluée. Les propriétés rhéologiques et de stabilité thermique ont notamment été étudiées. Quelques essais de rotomoulage sur les systèmes les plus pertinents ont également été réalisés et ont démontré des résultats encourageants. Dans une dernière partie, les propriétés barrière aux gaz de ces systèmes PA6 ont été étudiées. Les perméabilités mesurées ont été interprétées en tenant compte de la morphologie des mélanges. En particulier, cette étude montre que les nanocomposites à base de PA6 et de graphite lamellaire présentent des performances adaptées pour l’application en raison de l’effet de tortuosité induit par la charge. Les propriétés mécaniques en traction uniaxiale des systèmes élaborés ont finalement été déterminées et confrontées aux spécifications requises. Les résultats obtenus montrent que les caractéristiques mécaniques sont tout à fait adaptées pour une utilisation en tant que liner de réservoir de stockage d’oxygène liquide. / In the field of transport, the development of lighter, cheaper and more efficient structures is a recurrent challenge. Polymer materials are good candidates for these applications due to their characteristics quite suitable for requirements. This Phd work aims at developing a thermoplastic material which will be used as an internal liner of a liquid oxygen (LOX) storage tank. The objective is to demonstrate a 20 % to 30 % weight saving, compared to metallic structures. To be used in this kind of application, the thermoplastic material must be LOX compatible, processable by rotational moulding and display a low gas permeability as well as good mechanical properties at low temperatures. In a first part, LOX compatibility of polymers was studied. Taking into account theories proposed in the literature, polyamide 6 (PA6) nanocomposites based on LCP, fluoride and graphite fillers were processed and characterized in order to reach desired properties. The influence of several parameters having an impact on LOX behaviour of polymers was then investigated. The nanocomposites show overall good compatibility with liquid oxygen. This study also demonstrates that LOX sensitivity largely depends on the preparation of samples. The processability of nanocomposites by rotational moulding has then been investigated. Rheological properties and thermal stability have especially been studied. Some rotational moulding trials were carried out on the most relevant systems and demonstrate promising results. Finally, the gas transport properties of PA6 nanocomposites were studied. Measured gas permeability was discussed as a function of the morphology of blends. In particular, this study shows that PA6 nanocomposites filled with lamellar graphite present convenient performances which are due to the tortuosity effect induced by the filler. Mechanical properties of filled systems were finally determined and compared with set requirements. The results show that mechanical characteristics are quite relevant for use as internal liner of LOX storage tank.
187

Zur Warmlochformung in Textil-Thermoplast-Strukturen – Technologie, Phänomenologie, Modellierung

Kupfer, Robert 09 December 2021 (has links)
In vielen Bereichen des Leichtbaus haben sich Bolzen- und Nietverbindungen als zuverlässige und effiziente Verbindungstechniken für Mischbauweisen mit Faserverbunden etabliert. Diese Verbindungen bieten im Zusammenhang mit textilverstärkten Thermoplasten zusätzlich das Potential, die technologiebedingt erforderlichen Löcher durch warmlochformende Verfahren einzubringen. Im Gegensatz zu den klassischen Verfahren der Lochherstellung (z. B. Bohren) werden die lasttragenden Fasern hierbei nicht durchtrennt, sondern vorteilhafterweise seitlich in das Lochnahfeld verschoben. In dieser Arbeit werden die technologischen, experimentellen und theoretischen Voraussetzungen für die systematische Analyse dieser Lochformungstechnologie geschaffen und darauf aufbauend ihr Einsatzpotential für automatisierte Fertigungsprozesse aufgezeigt. / In many areas of lightweight engineering, bolted and riveted connections are established as reliable and efficient joining techniques for multi-material design with composites. In combination with textile-reinforced thermoplastics, these joints additionally offer the potential of introducing the required holes by warm-forming processes. In contrast to the classic methods of hole manufacturing (e.g. drilling), the load-bearing fibers are not cut, but advantageously shifted aside into the surrounding laminate. In this work, the technological, experimental and theoretical basis for the systematic analysis of this hole moulding technology are provided and, based on this, its application potential for automated manufacturing processes is demonstrated.
188

A new process chain for producing bulk metallic glass replication masters with micro- and nano-scale features

Vella, P.C., Dimov, S.S., Brousseau, E., Whiteside, Benjamin R. 05 September 2014 (has links)
Yes / A novel process chain for serial production of polymer-based devices incorporating both micro- and nano-scale features is proposed. The process chain is enabled by the use of Zr-based bulk metallic glasses (BMG) to achieve the necessary level of compatibility and complementarity between its component technologies. It integrates two different technologies, namely laser ablation and focused ion beam (FIB) milling for micro-structuring and sub-micron patterning, respectively, thus to fabricate inserts incorporating different length scale functional features. Two alternative laser sources, namely nano-second (NS) and pico-second (PS) lasers, were considered as potential candidates for the first step in this master-making process chain. The capabilities of the component technologies together with some issues associated with their integration were studied. To validate the replication performance of the produced masters, a Zr-based BMG insert was used to produce a small batch of micro-fluidic devices by micro-injection moulding. Furthermore, an experimental study was also carried out to determine whether it would be possible by NS laser ablation to structure the Zr-based BMG workpieces with a high surface integrity whilst retaining the BMG's non-crystalline morphology. Collectively, it was demonstrated that the proposed process chain could be a viable fabrication route for mass production of polymer devices incorporating different length scale features.
189

A service orientated architecture and wireless sensor network approach applied to the measurement and visualisation of a micro injection moulding process. Design, development and testing of an ESB based micro injection moulding platform using Google Gadgets and business processes for the integration of disparate hardware systems on the factory shop floor

Raza, Umar January 2014 (has links)
Factory shop floors of the future will see a significant increase in interconnected devices for monitoring and control. However, if a Service Orientated Architecture (SOA) is implemented on all such devices then this will result in a large number of permutations of services and composite services. These services combined with other business level components can pose a huge challenge to manage as it is often difficult to keep an overview of all the devices, equipment and services. This thesis proposes an SOA based novel assimilation architecture for integrating disparate industrial hardware based processes and business processes of an enterprise in particular the plastics machinery environment. The key benefits of the proposed architecture are the reduction of complexity when integrating disparate hardware platforms; managing the associated services as well as allowing the Micro Injection Moulding (µIM) process to be monitored on the web through service and data integration. An Enterprise Service Bus (ESB) based middleware layer integrates the Wireless Sensor Network (WSN) based environmental and simulated machine process systems with frontend Google Gadgets (GGs) based web visualisation applications. A business process framework is proposed to manage and orchestrate the resulting services from the architecture. Results from the analysis of the WSN kits in terms of their usability and reliability showed that the Jennic WSN was easy to setup and had a reliable communication link in the polymer industrial environment with the PER being below 0.5%. The prototype Jennic WSN based µIM process monitoring system had limitations when monitoring high-resolution machine data, therefore a novel hybrid integration architecture was proposed. The assimilation architecture was implemented on a distributed server based test bed. Results from test scenarios showed that the architecture was highly scalable and could potentially allow a large number of disparate sensor based hardware systems and services to be hosted, managed, visualised and linked to form a cohesive business process.
190

Injection moulded controlled release amorphous solid dispersions: Synchronized drug and polymer release for robust performance

Deshmukh, Shivprasad S., Paradkar, Anant R, Abrahmsén-Alami, S., Govender, R., Viridén, A., Winge, F., Matic, H., Booth, J., Kelly, Adrian L. 26 October 2020 (has links)
Yes / A study has been carried out to investigate controlled release performance of caplet shaped injection moulded (IM) amorphous solid dispersion (ASD) tablets based on the model drug AZD0837 and polyethylene oxide (PEO). The physical/chemical storage stability and release robustness of the IM tablets were characterized and compared to that of conventional extended release (ER) hydrophilic matrix tablets of the same raw materials and compositions manufactured via direct compression (DC). To gain an improved understanding of the release mechanisms, the dissolution of both the polymer and the drug were studied. Under conditions where the amount of dissolution media was limited, the controlled release ASD IM tablets demonstrated complete and synchronized release of both PEO and AZD0837 whereas the release of AZD0837 was found to be slower and incomplete from conventional direct compressed ER hydrophilic matrix tablets. Results clearly indicated that AZD0837 remained amorphous throughout the dissolution process and was maintained in a supersaturated state and hence kept stable with the aid of the polymeric carrier when released in a synchronized manner. In addition, it was found that the IM tablets were robust to variation in hydrodynamics of the environment and PEO molecular weight. / The research was funded by AstraZeneca, Sweden.

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