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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.
271

Développement de mélanges chargés en poudres d'aluminure de titane pour moulage par injection et applications aéronautiques / Development of mixtures of polymers loaded whith titanium aluminide alloys - Injection molding and aerospace

Tourneroche, Paul 22 March 2016 (has links)
La réduction de l’impact des activités humaines sur l’environnement est au sujet de nombreux programmes de recherche. Ainsi, dans le domaine du transport aérien a été créé le projet Clean-Sky, regroupant les thèmes de recherche associés. La thèse, partie de ce dernier, a pour objectif de réduire l’impact environnemental de la production de composants en alliages avancés à base de Titane. La production actuelle ayant une empreinte écologique non négligeable, un procédé de fabrication alternatif est étudié, il s’agit du moulage par injection de poudres métalliques. La première partie de cette consiste donc en la recherche d’une formulation de mélange optimale parmi les solutions classiques et innovantes. Elles sont triées en fonction de leurs aptitudes, déterminées par caractérisations physico-chimiques, à assurer le bon déroulement de chaque étape du procédé. Un nombre réduit de solution étant ainsi dégagé, il s’agit de passer aux étapes d’injection, de déliantage et de frittage. Plusieurs géométries de pièces sont testées dans chacun de ces cas, afin de valider l’adaptation aux différentes contraintes imposées. Lors de ces trois phases, des analyses physico-chimiques complètes permettent de mettre en avant la ou les formulations les plus aptes à permettre la production de ces composants. Une fois la solution fixée, chaque étape du procédé est optimisées, afin de faciliter le transfert industriel et d’assurer la rentabilité du nouveau processus de fabrication. Ces travaux de doctorat ont permis de mettre en avant deux formulations, répondant aux critères définis en début de thèse. Les étapes de mélange, injection, déliantage et frittage ont été optimisées et le transfert industriel est possible. / Reducing the ecological footprint of human activities is, today, the aim of most of the research programs. In Europe, the « Clean Sky » project funds research activities to make air transport « greener ». This PhD, being part of it, is about improving production of Titanium Aluminide based components. Nowadays production having a strong environmental impact, an alternative way has been investigated: metal injection molding. The first step of this work was focused on a bibliographic study, to select relevant, common and innovative mixtures to be used in the process. Throughout the process, these mixtures have been tested, physically and chemically analyzed, to get data about the optimal mixture. Several components geometries have been tested, during injection, debinding, and sintering steps. Once the mixture(s) chosen, process’ parameters have been optimized to make industrial transfer easier, and lower its overall cost. The developments achieved during this PhD led to two qualified mixtures, and optimized mixing, molding, debinding and sintering steps.
272

Modélisation multi-physiques et simulations numériques du moulage par injection mono et bi matières thermoplastique / silicone liquide / Multiphysics modeling and numerical simulation of mono and bi materials injection molding of thermoplastic / liquid silicone

Ou, Huibin 02 February 2015 (has links)
La famille des élastomères silicones LSR (Liquid Silicone Rubber) de haute technicité est identifiée comme celle possédant les plus forts arguments de développement au cours des prochaines décennies en raison de leurs propriétés spécifiques et de leurs facilités de mise en forme en grande série. Notamment, le moulage par injection du LSR sur d’autres matières telles que les thermoplastiques ou les métaux est aujourd’hui possible, ce qui ouvre la possibilité d’obtenir des composants multi-matières, multi-couleurs et de nouvelles fonctionnalités. Cette thèse se concentre sur la transformation des élastomères silicones LSR dans le but de mieux appréhender les phénomènes impliqués, afin d’améliorer les procédés d’élaboration et d’optimiser les conditions de transformation des composants élastométriques mono ou bi-matières à géométrie et propriété fonctionnelle bien définie. Les comportements rhéologique, cinétique et thermique des élastomères silicones ont été étudiés et caractérisés sous des conditions réelles de mise en œuvre par différentes méthodes associées. Un modèle thermo-rhéo-cinétique a été développé et ensuite implémenté dans un code de calcul de remplissage Cadmould® pour simuler le moulage par injection des élastomères silicones LSR ou encore le surmoulage de thermoplastiques. Pour la validation des modèles choisis et des paramètres identifiés, les essais d’injection sur l’outillage industrielle instrumenté ont été réalisés et confrontés à des résultats numériques obtenus. Enfin, la caractérisation de l’adhésion et l’adhérence interfaciale entre les thermoplastiques et les élastomères silicones a été réalisé sous différentes sollicitations complexes. De plus, l’évolution d’adhérence interfaciale des assemblages collés au cours de la vulcanisation des élastomères silicones a été caractérisée par l’essai de traction en utilisant un rhéomètre rotatif sous différentes modes de chauffage. / The family of high technology silicone elastomers LSR (Liquid Silicone Rubber) is identified as having the strongest arguments for development in the coming decades due to their unique properties and easy forming in large series. In particular, the injection molding of LSR on other materials such as thermoplastics or metals is possible today, which opens the possibility of obtaining multi-material, multi-color and new features components. The work presented in this thesis focuses on the transformation of silicone elastomers in order to better understand the phenomena involved, as to improve production processes and optimize processing conditions for mono or bi-material components in geometry and property functional well defined. The rheological, curing kinetic and thermal behaviors of silicone elastomers have been studied and characterized under real conditions of production by different methods combined. A thermo-rheo-kinetic model was then developed and implemented in commercial computer software Cadmould® to simulate the injection molding process of LSR or the overmolding process of LSR on to thermoplastics. For the validation of the models chosen and the parameters identified, the injection molding tests on industrial instrumented tools were performed and compared to numerical results. Finally, the characterization of interfacial adhesion between the thermoplastic and silicone elastomers was carried out under various adhesion tests. Moreover, the evolution of interfacial adhesion in thermoplastic/silicone components during the vulcanization of silicone elastomers has been characterized by the tensile test using a rotating rheometer in different heating cycles
273

Optimalizace jádra formy na vstřikování plastů / Optimization of core molds for injection molding

Stavárek, Václav January 2019 (has links)
Diplomová práce vznikla ve spolupráci s průmyslovým partnerem, který vyrábí elektrické komponenty pro automobilový průmysl. Tato firma se potýká s problémy často se porušujících jader v některých jejich formách na vstřikování plastů, vyrábějících převážně housingy pro konektory. Firma disponuje licencemi na komerční software pro simulaci injekčního vstřikování Moldflow a Moldex3D a také pro simulaci metodou konečných prvků Ansys. Nejprve jsou shrnuty teoretické poznatky ohledně injekčního vstřikování a jeho simulace, řešení problémů interakce těles s tekutinou a únavy materiálu. Poté je popsán proces stanovení únavové životnosti jádra formy s využitím výše zmíněného softwaru. Proces je vysvětlen na příkladu konkrétní formy ve výrobě této firmy. Je zvolen takový přístup vyhodnocení únavy, který nejvíce odpovídá současné životnosti jader, a ten je pak použit pro analýzu vlivu změny geometrie jádra a parametrů vstřikování. Změny ostatních parametrů, které simulace neumožňuje zahrnout, jsou rovněž navrhnuty a pokud možno odůvodněny jinými způsoby. Jedno z doporučení je přidání zaoblení na obě jádra, což by mohlo prodloužit životnost toho problematičtějšího z nich z 30 dnů na více než 320 dnů. Toto by mohlo znamenat úspory až 10 600 EUR ročně. Další doporučení je změnit způsob obrábění jader a také přidat jejich tepelné zpracování.
274

Výroba součásti Dvojité koleno HTHT32/40 GI / Production of HTHT32 / 40 GI Double Elbow

Kříbala, Milan January 2020 (has links)
The diploma thesis deals with the design of an injection mold for manufacturing double elbow, which finds its use in the siphon assembly. The part will be made of polypropylene with the trade name Tatren HT 25 11. The production batch size is set at 100,000 units in 3 months. Firstly, the analysis of the part is done including a detailed specification of its function and criteria that must be met by the component. Furthermore, a suitable technology for the production of the part is chosen. The theory of injection molding and mold design is made on the basis of the chosen injection technology. Subsequently, in the practical part is made a complete design of injection mold including technological calculations and simulations. An injection molding machine is chosen for the proposed injection mold. The conclusion of the thesis consists of technical - economic evaluation of the production of double elbow.
275

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.
276

Kontrola kvality vstřikovaných plastů pomocí rentgenové počítačové tomografie / Quality control of injection molded plastics using X-ray computer tomography

Figar, Erik January 2020 (has links)
This Master‘s thesis deals with an aplication of computed tomography as the technology for quality control check of the plastic parts made by the injection molding process. The analyses were performed on two different types of plastic parts. These parts were delivered by two companies and they included the drawing documentation and CAD models. These plastic parts were analyzed according to their qualitative requirements. The analyses included evaluation of the geometric tolerances and porosity analysis with numerical and graphical evaluation. The new module for tool correction ,which is part of VGStudio Max, was tested on parts that were not in accordance with the required tolerances. Afterwards the new corrected geometries were exported. At the end of this Master’s thesis the porosity comparison was assessed between two different voxel resolution CT data. This comparison shows the complexity of this phenomenon and the importance of voxel resolution settings.
277

Konstruktion av kopplingsmekanism för ett delat skaft : Förslag på konstruktionsförbättringar för produkten SverigeGrepen / Design of a coupling mechanism for a split shaft

Åström, Viktor, Näsman, Erik January 2021 (has links)
Följande examensarbete handlar om att ta fram konstruktionsförslag för en kopplingsmekanism som möjliggör delning av SverigeGrepens stallgrep. Produkten SverigeGrepen är med sin särskilda utformning och låga vikt ett ergonomiskt mockningsredskap. På grund av dess längd och form tillkommer en avgift för skrymmande paket vilket resulterar i en hög fraktkostnad. En lösning på detta problem är att skaftet delas itu, vilket tillåter produkten att fraktas i ett mindre paket. Vid ankomst hos kund monteras produkten med hjälp av kopplingsmekanismen. Lösningen ska innebära en minimal påverkan på egenskaper jämfört med hur produkten ser ut idag, som vikt och hållfasthet. För att erhålla ett teoretiskt underlag för problemet genomfördes en litteraturstudie. Denna behandlade områden som formsprutning och konstruktionsregler, finita elementmetoden, material, konceptval samt tidigare studier. Studien fortsatte med benchmarking och framställandet av en produktkravspecifikation. Dessa användes som grund för att generera olika koncept, där de mest lovande konstruerades i CAD. Metoder för konceptval applicerades, där slutligen två av koncepten valdes att kombineras inför en vidareutveckling. Resultatet av arbetet är ett konstruktionsförslag för en pluggliknande kopplingsmekanism som monteras på skaftets insida. Denna lösning har en låg vikt, klarar vardaglig belastning och tillåter montering av SverigeGrepens delade skaft. / This thesis aim is to develop a design proposal for a coupling mechanism for SverigeGrepen’s mucking tool which enables a splitting of its shaft and thus subsequently offer the ability to reliably mount them back together. SverigeGrepen is a lightweight product with a special design that makes it an ergonomic mucking tool. Due to the products length and shape a package fee is added in conjunction with its shipping which results in a high delivery cost. A proposal to solve this problem is a splitting of its shaft, which allows the product to be shipped in a smaller package. The product is assembled upon arrival at the customer. The solution should also have a minimal negative impact on SverigeGrepen’s existing product, such as its weight and strength. A literature study was conducted to obtain a theoretical basis. The study treated areas such as injection molding and rules for plastic design, as well as the finite element method, materials, concept selection and previous research. The study continued with market research and the development of a product requirement specification. These were used as a basis for generating product concepts, of which the most promising drafts were designed in CAD. Methods for concept selection were applied, where finally two of the concepts were chosen to be combined for further development. The result is a design proposal for a plug-like coupling mechanism that is mounted on the inside of the products shaft parts. The proposed solution offers a low total weight, endure the stress associated with everyday usage and allows the assembly of SverigeGrepen’s splitted shaft parts.
278

Řízení průběhu zakázky organizací / Manufacuring Order Management in Company

Ružbacký, Bohumil January 2011 (has links)
This master's thesis is focused on analyzing problems during the execution of contracts selected company, which deals with custom manufacturing thermoplastic injection molding. The thesis proposed possible solutions for identified problems.
279

Konstrukce plastových dílů předního nárazníku sportovního automobilu / Design of plastic parts of the sports car front bumper

Najvar, Petr January 2011 (has links)
This thesis deals with the plastic parts design for VW Scirocco R front bumper. Plastic parts were designed for an injection molding mass production. Besides of designing a shape of the parts based on package, assembly concept, functional and aesthetic requirements, great deal of attention is applied to proper part molding with regard to technological and economic aspects.
280

Automatizovaný dopravníkový zásobník pro vstřikovací lis s manipulátorem / Manipulator automati conveyor container for injection molding machine

Rychtářík, Jan January 2011 (has links)
The thesis is focused on proposal of automatic transport feeder that can be used for injection moulding machines. It is concerned with conveyor belt, gravitational roller line and lift. Proposal of construction of automatic transport feeder, calculation of drive for conveyor belt and driven line is contained in this thesis. There is calculation of driveshaft, proposal of spring and calculation of bearing lifetime. Angle of conveyor of gravimetric roller line and speed at the end are calculated. Calculation of proposal of drive for lift and proposal of drive roller line on the lift is here. This thesis contains senzor, operation and steering, safety protection of feeder. There are applicability of robotic workplace and economic calculation at the end of thesis.

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