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The following report conducted with the collaboration with the University of Halmstad and Halmstad Gummi Fabric (HGF) rubber company which is in Halmstad. The focus on the project is to reduce the cost of the transfer mold material, increase efficiency of production, save energy and redesign the transfer mold. The methodology used in this project is based on the Quality Functional Deployment (QFD) which is widely appreciated globally in the product development, and other product development and mold design methods, FEM analysis are applied to achieve the goals. The implementation of this methods is efficient and beneficial to reduce the material cost and redesign the transfer mold without compromising the initial quality of the product. This thesis resulted in, for the transfer molding plates we recommended the proper material for the plates and the insulation parts. And we redesign the transfer mold plates and optimized the design for reducing the cost. We did FEM analysis for optimization purpose, and the benefits to optimizing this is to reduce the material cost, machining cost and labour cost. As well as, we add the insulation plates in the design so that the transfer molding plates works efficiently with the reducing the energy wastes.

"Aluminum-Silicon and Aluminum-Copper alloys are important non-ferrous casting alloys. Different methods have been applied to improve their casting characteristics, their microstructure and consequently, their mechanical properties. Application of mechanical vibrations to the mold during solidification of the alloy is one of these methods. In this study, the effect of controlled mechanical vibrations on the dendrite coherency point, the hot tearing tendency, and the microstructure of B206, B390, and binary Al-7%Si alloys was evaluated. The dendrite coherency point was determined using the two-thermocouple method. The hot tearing tendency was evaluated using the crack susceptibility criterion (CSCb) and by means of measurements using a specially designed ring mold. Microstructure characterization was performed using optical and scanning electron microscopy coupled with image analysis. It was found that mechanical vibrations refine the microstructure of the alloys; and, in the case of B390 alloy, it resulted in significant improvement in the distribution of the primary silicon particles. In the case of B206 and Al-7%Si alloys, where aluminum is the primary phase, mechanical vibrations caused the dendrite coherency point to shift towards lower temperature, i.e., towards higher fraction solid. This shift, together with the refinement of the grain structure, manifested itself in significant reduction in the incidence of hot tearing in B206 castings. "

Thesis. 1976. M.S. cn--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by John R. Potter. / M.S.cn

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by James R. Rinderle. / M.S.

Na presente pesquisa, produziu-se amostras de ferro puro poroso como biomaterial degradável visando a aplicação em stents, pelo processo de moldagem por injeção de pós metálicos (MPI). Os efeitos da fração volumétrica de ferro puro na mistura de injeção e da temperatura de sinterização na porosidade, microestrutura, propriedades mecânicas, propriedades de superfície, de degradação in vitro e de biocompatibilidade, foram investigados. Os resultados obtidos foram comparados com o ferro puro fabricado por fusão e com o aço inoxidável AISI 316-L. Encontrou-se que o grau de porosidade remanescente nas amostras sinterizadas foi o principal fator influenciando as propriedades mecânicas e de superfície, influenciando indiretamente os demais resultados. O ferro puro produzido por MPI exibiu valores de limite de escoamento entre 59 e 114 MPa e limite de resistência máximo de 210 MPa, com alongamento entre 10 e 50 %. A alta ductilidade é uma propriedade especialmente requerida em materiais para potencial aplicação em stents. Suas taxas de degradação em solução de Hank foram superiores às do ferro puro fabricado por fusão. O material fabricado com mistura de injeção contendo fração de ferro de 66 % (acima da fração crítica) mostrou o maior alongamento e boa taxa de degradação, um resultado interessante, pois segundo a literatura, valores acima da fração volumétrica crítica não são amplamente explorados. Os testes de biocompatibilidade mostraram excelente hemocompatibilidade do ferro puro fabricado por MPI com as células do sangue. Todas as condições testadas mostraram um nível de citotoxicidade abaixo do recomendado pela norma vigente, mas este dependendo da concentração de íons de ferro empregada e do grau de porosidade. Entre todas as condições de ensaio investigadas, as amostras contendo fração volumétrica de ferro de 62 % inicialmente na mistura de injeção e sinterizadas a 1120 oC, apresentaram a melhor combinação de propriedades para aplicação em stents. Concluiu-se que a MPI é um método tecnicamente viável como rota de produção de tubos de parede fina precursores para fabricação de stents biodegradáveis. / In the present research, an attempt was made to produce porous pure iron, as a metallic degradable biomaterial potentially for stent application, via the MIM route. The effects of iron powder loading and sintering temperature on the porosity, microstructure, mechanical properties, surface properties and in vitro degradation behavior of MIM iron were investigated. The results obtained were compared to those of cast iron. It was found that the amount of porosity remained in the as-sintered specimens had a major effect on their surface and mechanical properties. The MIM pure iron showed yield strength values between 59 and 114 MPa and maximum tensile strength of 210 MPa, with elongation values between 10 and 50 %. A high ductility is a specially required property of stent materials. Its degradation rates in Hank’s solution were superior to the degradation rate of cast iron. The material made from the feedstock containing 66 % of iron powder, above the critical powder loading, showed the highest elongation and a good in vitro degradation rate. This result is interesting, once according to the literature, powder loadings above the critical value are not well explored. The biocompatibility tests showed excellent hemocompatibility of MIM pure iron with blood cells. All conditions tested showed toxicity level below the values determined by current standards, but depending of Fe ions concentration and porosity level. Between all the conditions tested in the present investigation, the 62 % powder loading sample, sintered at 1120 oC, showed the best combination of properties for stent application. In conclusion, MIM is a promising method to be developed as a new route to produce thin-wall tubes for biodegradable stents.

The purpose of this research is to empirically investigate flow front void formation rates and post-formation bubble mobility behavior for composites produced via resin transfer molding (RTM).For this study, in situ observation of bubble formation and migration was accomplished by photographing resin flow progression during infusion tests of carbon reinforcements. An analysis strategy for use in batch processing sequential image sets is presented. The use of MATLAB to process and analyze binary images of infusions for void content has garnered satisfactory results and has shown that analysis of progressive image sequences can greatly enrich the volume of in situ measurements for a given study without compromising the data quality.Semi-automated MATLAB software analysis employed the representative image area (RIA) method to evaluate v0. It was found that the shorter the RIA length, and the more it follows the true flow front shape, the more representative the measured v0 was of the void formation at the flow front.Experimental evidence of in situ bubble formation and mobility behavior is presented. Stitch architecture of NCF reinforcements is shown to influence bubble formation at the flow front. Bubble mobility mechanisms (such as escape and entrapment) are related to stitch orientation relative to the fluid flow direction. Different stitching orientations exhibited different effects on post-formation mobility.Void formation is presented as a function of flow front velocity. Despite differences in preform configurations (stitch orientation with respect to flow) and injection flowrates, bubbles seem to form in a similar fashion for the 3 infusions of carbon fiber NCF reinforcement analyzed in this study. It is observed that bubbles form at stitch lines, regardless of stitch orientation.Bubble migration is documented for infusion of NCF reinforcement with stitching at different orientations. Qualitative observations of bubble migration during infusions of a dense preform of STW, plain weave fabric are discussed. Recommendations are given for future studies involving image-based analysis of in situ bubble formation and migration.

Vacuum forming is a popular, cost effective method amongst large and small scale applications. The method is used to mold a material to the surface of a mold/pattern in order to create a negative copy for reproduction or an object in positive form. The prototype vacuum forming system developed and documented herein is of a membrane-seal type that consists of three (3) principle parts: radial platen, Hinged Frame and Platen Support Assembly, and a PVC surge tank. Each part is described in detail through design, manufacturing, and testing processes. The design supports functional versatility, small scale molding, and uses readily available materials. Functional prototype testing was performed with the thermoplastic KYDEX® and multiple objects for mold examples. Results include successful proof of concept, design pros and cons, and findings based on functional testing.

As the aerospace industry continues to incorporate composites into its aircraft, there will be a need for alternative solutions to the current autoclaving process. Liquid composite molding (LCM) has proven to be a promising alternative, producing parts at faster rates and reduced costs while retaining aerospace grade quality. The most important factor of LCM is controlling the resin flow throughout the fiber reinforcement during infusion, as incomplete filling of fibers is a major quality issue as it results in dry spots or voids. Void formation occurs at the resin flow front due to competition between viscous forces and capillary pressure. The purpose of this work is to characterize capillary pressure in vacuum infusion, and develop a model that can be incorporated into flow simulation. In all tests performed capillary pressure was always higher for the carbon fiber versus fiberglass samples. This is due to the increased fiber packing associated with the carbon fabric. As the fabric samples were compressed to achieve specific fiber volumes an increase in capillary pressure was observed due to the decrease in porosity. Measured values for capillary pressure in the carbon fabric were ~2 kPa, thus the relative effects of Pcap may become significant in flow modeling under certain slow flow conditions in composite processing.

<p>In later years polymer replication techniques have become a frequently employed fabrication method for microfluidic and micro-optical devices. This thesis describes applications and further developments of microstructures replicated in polymer materials. </p><p>A novel method for homogenous amplified single-molecule detection utilizing a microfluidic readout format is presented. The method enables enumeration of single biomolecules by transforming specific molecular recognition events at nanometer dimensions to micrometer-sized DNA macromolecules. This transformation process is mediated by target specific padlock probe ligation, followed by rolling circle amplification (RCA) resulting in the creation of one rolling circle product (RCP) for each recognized target. Throughout this transformation the discrete nature of the molecular population is preserved. By hybridizing a fluorescence-labeled DNA detection oligonucleotide to each repeated sequence of the RCP, a confined cluster of fluorophores is generated, which makes optical detection and quantification possible. Spectral multiplexing is also possible since the spectral profile of each RCP can be analyzed separately. The microfluidic data acquisition process is characterized in detail and conditions that allow for quantification limited only by Poisson sampling statistics is established. The molecular characteristics of RCPs in solution are also investigated.</p><p>Furthermore a novel thermoplastic microfluidic platform is described. The platform allows for observation of the microchannels using high magnification optics and also offers the possibility of on-chip cell culture and the integration of mechanical actuators.</p><p>A novel fabrication process for the integration of polymer micro-optical elements on silicon is presented. The process is used for fabrication of a micro-optical system consisting of a laser and a movable microlens making beam steering possible. Such a micro-scanning system could potentially be used for miniaturized biochemical analysis.</p>