• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 44
  • 15
  • 8
  • 4
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 95
  • 35
  • 27
  • 25
  • 21
  • 13
  • 12
  • 11
  • 10
  • 9
  • 8
  • 8
  • 8
  • 8
  • 8
  • 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.
51

Rapid Tooling and the LOMOLD Process

Joubert, Francois 12 1900 (has links)
Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2005. / The LOMOLD process is a new plastic moulding process being researched at the University of Stellenbosch. The process essentially combines injection moulding and compression moulding. Molten plastic is forced into the mould cavity using a plunger. This plunger then forms part of the cavity wall. The plunger face must therefore follow the geometry of the part. Rapid Tooling evolved from Rapid Prototyping. There are two categories of Rapid Tooling: indirect and direct rapid tools. Indirect rapid tools are manufactured by using a master pattern to form the mould cavity. The accuracy of the mould cavity depends heavily on the accuracy of the master pattern. The master pattern is usually produced using Rapid Prototyping technology. Direct rapid tools use Rapid Prototyping technology to build the mould through and additive, layer by layer process or a subtractive process. This research investigates the use of Rapid Tools for the LOMOLD process. Aluminium Filled Epoxy Tooling (AFET) represents the indirect technology and CNC-machined tooling the direct technology. Both of these technologies are available at the University of Stellenbosch. Parts are manufactured on these tools using an experimental LOMOLD machine. These two technologies are compared in terms of part accuracy, tool lead time, tool cost and part cost. The research concluded that the only advantage the AFET has over the CNC-machined tool is a shorter manufacturing lead-time. In terms of tool cost, tool life, part geometric accuracy, part cost and cycle time the CNC tool is superior. Therefore the application of AFET is limited to small volume, prototype or pre-production runs for tool design confirmation, part functional testing and part appearance testing. It is also demonstrated that a cooling system on the AFET tool has no significant influence on the tool performance and should therefore, especially for production runs less than 150 parts, not be included in the tool to save on tool cost. Another conclusion is that the LOMOLD process is not consistent enough for a production process. This statement could be limited to the machine used for the research but to prove this statement wrong, the machine must be improved and more investigation is required.
52

ESTUDO COMPARATIVO DA COMPETITIVIDADE DAS EMPRESAS DE MÁQUINAS FERRAMENTAS BRASILEIRAS: ANÁLISE MULTICRITÉRIOS

Sanches, João Carlos Santiago 15 February 2007 (has links)
Made available in DSpace on 2016-08-02T21:42:41Z (GMT). No. of bitstreams: 1 JOAO CARLOS SANCHES.pdf: 288041 bytes, checksum: 3c59f0a91370310bbcc60d22ea4c47e8 (MD5) Previous issue date: 2007-02-15 / The aim of the current study was to investigate through a comparative study, a competitive positioning of three Multitask and Tooling Machines in Brazilian market..Initial hypothesis were based on: a) the national tooling machine industries are being penalized with the industrial policies practiced by the federal government, and b) the relative importance attributed to multicriteria elements of the specifications of the national machines, when considered on the growing trends, are not always met by the imported competing machines as a result of aggregated technological values meant to reach plain competitiveness. Thus, we inquire: to what extent are the multitask and tooling machines selected for test are alighned with the chosen criteria and their relative importance appreciated by the two users of the machines. As a methodology the study adopted a multi-case study of two medium industries of the same sector. We used the multicriteria decision method through Analytic Hierarchy Process (AHP) so as to obtain the most suitable alternative between the national and imported multitasks similar machineries. Results indicate that for the two cases analyzed, it is advantageous to acquire the imported machines, even though it is notorious to mention the national technological advancement. These machines need innovations as they loose competitiveness, not to mention some important criteria such as versatility and productivity. Based on our findings therefore, we conclude that the national tooling and machines suppliers of the multitasks types analyzed in this study are not competitive as compared to the imported ones. / O principal objetivo desta dissertação foi analisar por meio de estudo comparativo, o posicionamento competitivo de três máquinas ferramentas multitarefas. As hipóteses iniciais partiram das seguintes suposições: a) a indústria nacional de máquinas ferramentas esta sendo penalizada pela política industrial praticada pelo governo federal; e b) a importância relativa atribuída aos elementos multicriteriais das especificações das máquinas nacionais quando demonstram tendências elevadas, nem sempre alcançam as concorrentes importadas devido aos recursos tecnológicos agregados para se atingir a competitividade plena. Assim, indaga-se: até que ponto as máquinas ferramentas multitarefas selecionadas para o estudo, estão alinhadas com os critérios escolhidos e com suas importâncias relativas avaliadas por dois usuários desse equipamento. Como metodologia adotou-se estudo de caso múltiplo de duas empresas de médio porte do mesmo ramo. Utilizou-se o método multicritério de apoio à decisão por meio de Analytic Hierarchy Process (AHP), para a escolha da melhor alternativa entre máquinas ferramentas multitarefas similares, nacionais e importadas. Os resultados identificam que, para essas duas empresas usuárias pesquisadas, existe vantagem na aquisição da máquina importada, embora seja notório o avanço tecnológico da indústria nacional. Estas máquinas ainda carecem de algumas inovações, perdendo em competitividade, bem como em critérios importantes como versatilidade e rendimento. Com base nos trabalhos, conclui-se que, as máquinas ferramentas do tipo multitarefas nacionais das duas empresas fornecedoras analisadas não são competitivas em comparação as importadas.
53

Marknadsundersökning kring additiv tillverkning i Sverige / Market research on Additive Manufacturing in Sweden

Tavajoh, Sara, Michael, Huynh January 2018 (has links)
Användningen och intresset för additiv tillverkning (AM) har ökat markant de senaste åren och det finns en teori kring att tillverkningsmetoden kan vara det nästa steget i den industriella revolutionen. Eftersom AM fortfarande befinner sig i utvecklingsstatidet går det att anta att tekniken ännu inte uppnått sin fulla potential och att det kan komma att finnas möjligheter att implementera tekniken i fler branscher och företag. Detta skulle innebära en bredare marknad för AM. Syftet med examensarbetet var att undersöka vilka möjligheter och hinder som finns för ökad användning av AM i Sverige. Studien genomfördes genom kvalitativa intervjuer med åtta olika verksamheter tillhörande den svenska industrin och en litteraturgenomgång för att presentera nuläget för AM i svensk industriell marknad. Resultatet av datainsamlingen analyserades med modellerna PEST, 4P och slutligen SWOT. De fördelar som har setts med användningen av AM har varit minskade ledtider, minskade kostnader för tillverkning av produkter och verktyg, minskat materialspill och en optimal designprocess med ökad kreativitet. De begränsningar som finns i tekniken i dagsläget är att priset för material och maskiner är dyrt. Vidare anses även kvalitet på slutdetalj, begränsad byggvolym och opålitliga processer vara problematiska. De möjligheter som finns beror huvudsakligen på den forskning som görs. Förutsättningarna för AM i svensk industri kommer att bero på hur tekniken kommer att utvecklas. De hinder som finns är kopplat till kompetensbrist och att det inte finns befintliga standarder för material eller process inom AM. / Within the industrial sector, an increased interest and usage of Additive Manufacturing (AM) throughout the decade has been formed. The layer-upon-layer building technology has been seen and recognized as one of the next industrial revolutionizing methods of production. As the technology is still in the trending and uprising phase it should be considered that its full potential has not yet been achieved, as large opportunities for implementation of AM exist and that new companies and markets have a growing interest in this technology. Through this study a market research was conducted to identify and present what opportunities and obstacles there are for an increased usage of AM in Sweden. A literature study on the Swedish market has been made to present the market as of today. Eight qualitative interviews have also been conducted with companies within the industrial sector to identify the areas of use within AM for production. The concepts and models used to analyze these questions was PEST, Marketing Mix and SWOT. The concluded results for advantages in using AM are shortened lead times, reduced costs of production of components and tools, reduced material waste and optimization of design processes with increased creativity. The concluded challenges are expensive materials and machine, the quality of finished components, limited printing volume due to the 3D-printers and reliability of printing processes. The finalized opportunities that are presented in this work are that AM is dependent on how much research on the subject and factors around it is done. How AM will be applied in the coming future revolves around the advancement in the technology. The obstacles that are found in this study are lack of competence and lack of standard for materials and processes within AM.
54

Prototipagem rápida e ferramental rápido aplicados às peças utilizadas em ensaios estáticos de embalagens para acondicionamento e transporte de peças automotivas. / Rapid prototyping and rapid tooling applied parts used in in static tests of racks for packaging and transporting automobile parts.

Guilherme Canuto da Silva 25 September 2008 (has links)
A necessidade deste trabalho se fez no setor de Planejamento de Fluxo de Materiais e Embalagens (PFME), que pertence ao departamento de engenharia de manufatura de uma filial de montadora instalada no Brasil. Neste setor existe a necessidade de se obter peças protótipo em um menor espaço de tempo possível para realização dos ensaios estáticos dos protótipos das embalagens especiais, uma vez que as embalagens precisam acondicionar as peças produzidas a partir da fase de preparação da produção em série do automóvel (pré-série ou PVS). Neste trabalho, a partir do estudo das tecnologias de Rapid Prototyping (RP) - Prototipagem Rápida (RP) e Rapid Tooling (RT) Ferramental Rápido (RT) é selecionada a técnica mais adequada para se atender às necessidades deste setor. Para isto, algumas condições de contorno foram consideradas: a aplicação das técnicas de RP e RT foram restringidas às peças externas do carro como portas, tampas dianteiras, traseiras e pára-lama e as fontes fornecedoras consultadas encontram-se no mercado doméstico. Com base em um estudo de caso pode-se validar esta proposta. Os resultados obtidos com a aplicação da técnica de ferramental rápido Vacuum Bagging foram uma redução média de 4,5 meses na obtenção das peças protótipo e uma redução global dos custos de aquisição de aproximadamente R$ 100.000,00. / The need of this work was made in the material flow planning and packing (PFME) section, that belongs to the manufacture engineering department of an assembler company installed in Brazil. In this sector, there is a growing need to obtain prototype parts in the shortest time possible in order to carry out static prototype tests of the special packing, since these racks need to be ready to assist the preparation phase of the series production of the vehicle (pre series or PVS). In this work, beginning from the study of Rapid Prototyping (RP) and Rapid Tooling (RT) technologies is selected the technique more adequate to assist to the needs of this section. For that purpose, some limiting conditions were considered: the application of the RP and RT techniques is limited to the external parts of the vehicle, such as doors, front and back hoods and fenders, and the consulted suppliers should be available in the domestic market. Based in a case study this proposal could be validated. The obtained results with the applied Rapid Tooling Vacuum Bagging technique were a medium reduction of 4,5 months in the prototype parts acquisition and a global reduction in the acquisition costs of approximately R$ 100.000,00.
55

"Manufatura rápida - avaliação das tecnologias de impressão 3D e FDM na fabricação de moldes rápidos" / Rapid Manufactory – Comparative evaluations of 3D printing system against FDM system for Rapid Tooling

José Roberto Martins 16 May 2006 (has links)
Este trabalho avaliou a aplicação das tecnologias de prototipagem rápida por Impressão 3D e FDM (Fused Deposition Modeling) na produção de moldes rápidos. Esta avaliação foi feita com base nas qualidades das peças obtidas por vazamento nos moldes produzidos, bem como nas limitações encontradas em suas utilizações. Foram estabelecidas as principais diferenças do ponto de vista de qualidade, custos, tempos gastos e praticidade. Foram construídos moldes para peças que contemplando vários graus de dificuldades. Para cada ferramental foram obtidos lotes de peças, através dos quais foram analisadas e comparadas as qualidades dos protótipos. / This work evaluated the application of the Rapid Prototyping technologies 3D printer and FDM (Fused Deposition Modeling) in the rapid manufacturing of molds. This evaluation is based on the quality of the parts molded, as well as in the limitations found in the molds applications. As result the main differences related to quality, and usability was established. The molds produced parts with different degrees of geometric difficulties. For each mold, a few prototypes were produced and their qualities compared.
56

Studies On Wavefront Estimation And Refraction Corrected Image Reconstruction In Optical Tomography

Datta, G Keshava 04 1900 (has links) (PDF)
No description available.
57

Konstrukce revolverové hlavy pro CNC soustruh s přímým pohonem / Design of direct drive tool turret for CNC lathe

Mrkos, Jan January 2021 (has links)
The diploma thesis deals with the design of a direct drive tool turret, which serves as a tool magazine for a CNC lathe. In the introductory part of the work, a research was performed in the field of automatic tool change with a focus on tool turrets and their main structural units. The introductory research is followed by the main part of the work, which begins with the selection of appropriate design solutions, followed by a presentation of the tool turret design created in CAD software Autodesk Inventor 2021 and in the final part of thesis the key elements of the proposed design are verified by calculations.
58

Utilización de la tecnología del sinterizado selectivo por láser en el sector del juguete

Sánchez Reche, Ana María 19 November 2019 (has links)
El sector del juguete efectúa cada temporada grandes esfuerzos en el lanzamiento de nuevos productos. El fabricante cada vez se apoya más en la utilización de prototipos que le permitan presentar el producto en ferias y conocer los factores de éxito del diseño con un coste menor, a la vez que comprobar la funcionalidad y características técnicas del modelo. Sin embargo, la obtención del prototipo y del molde es un proceso que, a menudo es costoso, largo (1-2 meses) y muchas veces es preciso efectuar retoques en el molde obtenido. La aparición de las tecnologías de prototipado rápido como el Sinterizado Selectivo por Laser, ha reducido en gran medida la problemática asociada a la fabricación de los prototipos y moldes-prototipo. Sin embargo, la metodología de trabajo asociada a dicha tecnología, en concreto para fabricación de moldes (Rapid Tooling), no se encuentra optimizada y, en consecuencia no está aprovechada por el sector. La investigación derivada de la presente Tesis tiene como objetivo el de seleccionar cual es la técnica más apropiada y en esta, investigar, desarrollar, sistematizar y, finalmente, optimizar la metodología de desarrollo de moldes-prototipos, solucionando las limitaciones que hacen que no se pueda utilizar con resultados aceptables. Se ha realizado un estudio sobre las necesidades del sector del juguete, su situación tecnológica, su capacidad para incorporar nuevas tecnologías. También se han estudiado las técnicas de prototipado rápido y se han clasificado según su utilidad para fabricar prototipos y moldes-prototipo. Se han expuesto las ventajas y limitaciones de ellas, y se deduce que la mas útil para el sector del juguete es el Sinterizado Selectivo por Láser (SLS). Se estudian los parámetros críticos del proceso, el fundamento de al tecnología y su relación con las fabricación de prototipos para juguetes. Se han separado, clasificado y optimizado las características requeridas para obtener prototipos de plásticos y las de obtener prototipos metálicos y moldes-prototipos, y así se ha estudiado su relación con las variables del proceso de SLS como son la sinterización y la infiltración. Las variables seleccionadas que limitan los requisitos en la obtención de un prototipo en la fabricación de juguetes son: precisión, tamaño de la pieza y acabado superficial. Así, relacionando estas variables con el proceso de SLS se han obtenido los parámetros críticos y limitaciones para cada proceso de fabricación de prototipos. También se ha utilizado esta tecnología para comprobar su uso en la fabricación de diferentes tipos de moldes utilizados para obtener juguetes, y estos son: moldeo rotacional, extrusión, conformado, soplado, inyección de zamac y de plástico. Siendo en la fabricación de moldes-prototipo de inyección donde más ventajas aporta. Así analizando los resultados, las ventajas, limitaciones y teniendo presente que la mayoría de los juguetes se fabrican por inyección, es por lo que se considera necesario investigar sobre la elaboración moldes-prototipo para inyección. Para esta investigación se ha tenido en cuenta la relación de las características del sinterizado en conjunto con los requisitos del proceso de inyección y los moldes. Y de este estudio detallado se ha obtenido un procedimiento de trabajo o metodología que permite seleccionar los parámetros críticos a tener en cuenta dependiendo de la pieza que se desea fabricar. Con objeto de demostrar la utilidad en casos reales de esta nueva metodología se ha aplicado para la fabricación de piezas sencillas y complejas, tal como se ha expuesto en los resultados de esta Tesis. / Sánchez Reche, AM. (2007). Utilización de la tecnología del sinterizado selectivo por láser en el sector del juguete [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/131289
59

Low Coefficient of Thermal Expansion Composite Tooling Manufactured via Additive Manufacturing Technologies

Maravola, Michael January 2018 (has links)
No description available.
60

An Exploration of Rapid Tooling in Low-Cost Bead Foam Molding Applications

Dejager, Matthew Emerson 07 February 2024 (has links)
Many manufacturing processes require complex tooling which contributes significantly to the cost and time required to develop new products. Bead foam molding is often hampered by these limitations. This thesis presents an analysis of Additive Manufacturing (AM) applications in low cost bead foam molding, focusing on molding trials, economic analysis, and future potential. Through molding trials, the thesis evaluates the efficacy of AM tooling in comparison to traditional aluminum tooling, specifically in evaluating tool life and cost. A key finding is a reduction in lead time up to 70% and cost of up to 63% compared to traditional tooling, particularly in low-volume production scenarios. This thesis includes a detailed cost analysis, which breaks down the cost components associated with AM processes such as pre-processing, production, material costs, post-processing, and overheads. This analysis reveals that AM tooling can offer substantial cost savings over conventional methods, making it a viable option for specific manufacturing contexts. Findings suggest that while AM tooling shows significant promise in reducing costs and accelerating production in bead foam molding, further research is required. This research should focus on exploring the scalability of AM for larger tools and investigating the application of new and emerging AM processes and materials. / Master of Science / This thesis explores the use of Additive Manufacturing (AM), often known as 3D printing, in creating molds for bead foam molding—a process used in manufacturing a variety of foam products. Findings reveal that using AM for toolmaking can be faster and more cost-effective than traditional methods, especially for small-scale production. The thesis details experiments comparing AM with conventional tooling and presents a cost analysis showing the potential time and cost savings. While promising, further research is needed to fully harness the benefits of AM in this field. This study opens doors to more efficient and economical manufacturing techniques using emerging AM technology.

Page generated in 0.0431 seconds