The Experts below are selected from a list of 108 Experts worldwide ranked by ideXlab platform
C. Yuan - One of the best experts on this subject based on the ideXlab platform.
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The influence of autoclave steam on polymer and Organic Fibre modified ceramic shells
Journal of the European Ceramic Society, 2005Co-Authors: C. Yuan, S. Jones, Stuart BlackburnAbstract:Abstract The removal of wax from an unfired ceramic shell system without cracking or dimensional alterations is a key stage within the investment casting process. The effect of autoclave steam on polymer and Fibre modified investment casting mould behaviour has been investigated. The polymer modified system exhibited a higher mechanical strength in the green dry state, but that strength significantly reduced when subjected to a simulated autoclave “wet” condition, giving a 38% reduction in a flat bar section and a 45% reduction in an edge test. It is suggested that this is related to the softening of the latex particles when they are in contact with steam. In comparison the Fibre modified system showed a much lower reduction in strength when subjected to “wet” conditions. Calculating the adjusted fracture load (AFL) bearing capacity for the extra shell thickness of the Fibre system showed that the Fibre system outperforms the polymer system when the samples were tested “wet”, showing a 33% increase in a flat bar section and an increase of over 150% in the more vulnerable edge region. The results suggest that the effect of moisture must be taken into account when studying the shell behaviour under autoclave conditions.
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Organic Fibre modified ceramic shell moulding for investment casting
Materials Science and Technology, 2002Co-Authors: S. Jones, C. Yuan, K. LewisAbstract:AbstractInvestment casting research is being carried out by the University of Birmingham sponsored by the EPSRC and a consortium of industrial companies. The programme is aimed at developing a fundamental understanding of the process, with a view to routinely producing sound, net shape castings. The casting of liquid metals to produce solid objects is a manufacturing process, which has been practised for over five thousand years, with investment casting being one of the oldest known metal shaping methods. The technique itself has tremendous advantages in the production of quality components and key benefits of accuracy, versatility and integrity. As a result the process is one of the most economic methods of forming a wide range of metal components. Environmental and economic pressures have, however, resulted in a need for the industry to improve current casting quality, reduce manufacturing costs and explore new markets for the process. Optimisation of the mechanical and physical properties of the cerami...
S. Jones - One of the best experts on this subject based on the ideXlab platform.
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The influence of autoclave steam on polymer and Organic Fibre modified ceramic shells
Journal of the European Ceramic Society, 2005Co-Authors: C. Yuan, S. Jones, Stuart BlackburnAbstract:Abstract The removal of wax from an unfired ceramic shell system without cracking or dimensional alterations is a key stage within the investment casting process. The effect of autoclave steam on polymer and Fibre modified investment casting mould behaviour has been investigated. The polymer modified system exhibited a higher mechanical strength in the green dry state, but that strength significantly reduced when subjected to a simulated autoclave “wet” condition, giving a 38% reduction in a flat bar section and a 45% reduction in an edge test. It is suggested that this is related to the softening of the latex particles when they are in contact with steam. In comparison the Fibre modified system showed a much lower reduction in strength when subjected to “wet” conditions. Calculating the adjusted fracture load (AFL) bearing capacity for the extra shell thickness of the Fibre system showed that the Fibre system outperforms the polymer system when the samples were tested “wet”, showing a 33% increase in a flat bar section and an increase of over 150% in the more vulnerable edge region. The results suggest that the effect of moisture must be taken into account when studying the shell behaviour under autoclave conditions.
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Organic Fibre modified ceramic shell moulding for investment casting
Materials Science and Technology, 2002Co-Authors: S. Jones, C. Yuan, K. LewisAbstract:AbstractInvestment casting research is being carried out by the University of Birmingham sponsored by the EPSRC and a consortium of industrial companies. The programme is aimed at developing a fundamental understanding of the process, with a view to routinely producing sound, net shape castings. The casting of liquid metals to produce solid objects is a manufacturing process, which has been practised for over five thousand years, with investment casting being one of the oldest known metal shaping methods. The technique itself has tremendous advantages in the production of quality components and key benefits of accuracy, versatility and integrity. As a result the process is one of the most economic methods of forming a wide range of metal components. Environmental and economic pressures have, however, resulted in a need for the industry to improve current casting quality, reduce manufacturing costs and explore new markets for the process. Optimisation of the mechanical and physical properties of the cerami...
Stuart Blackburn - One of the best experts on this subject based on the ideXlab platform.
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The influence of autoclave steam on polymer and Organic Fibre modified ceramic shells
Journal of the European Ceramic Society, 2005Co-Authors: C. Yuan, S. Jones, Stuart BlackburnAbstract:Abstract The removal of wax from an unfired ceramic shell system without cracking or dimensional alterations is a key stage within the investment casting process. The effect of autoclave steam on polymer and Fibre modified investment casting mould behaviour has been investigated. The polymer modified system exhibited a higher mechanical strength in the green dry state, but that strength significantly reduced when subjected to a simulated autoclave “wet” condition, giving a 38% reduction in a flat bar section and a 45% reduction in an edge test. It is suggested that this is related to the softening of the latex particles when they are in contact with steam. In comparison the Fibre modified system showed a much lower reduction in strength when subjected to “wet” conditions. Calculating the adjusted fracture load (AFL) bearing capacity for the extra shell thickness of the Fibre system showed that the Fibre system outperforms the polymer system when the samples were tested “wet”, showing a 33% increase in a flat bar section and an increase of over 150% in the more vulnerable edge region. The results suggest that the effect of moisture must be taken into account when studying the shell behaviour under autoclave conditions.
K. Lewis - One of the best experts on this subject based on the ideXlab platform.
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Organic Fibre modified ceramic shell moulding for investment casting
Materials Science and Technology, 2002Co-Authors: S. Jones, C. Yuan, K. LewisAbstract:AbstractInvestment casting research is being carried out by the University of Birmingham sponsored by the EPSRC and a consortium of industrial companies. The programme is aimed at developing a fundamental understanding of the process, with a view to routinely producing sound, net shape castings. The casting of liquid metals to produce solid objects is a manufacturing process, which has been practised for over five thousand years, with investment casting being one of the oldest known metal shaping methods. The technique itself has tremendous advantages in the production of quality components and key benefits of accuracy, versatility and integrity. As a result the process is one of the most economic methods of forming a wide range of metal components. Environmental and economic pressures have, however, resulted in a need for the industry to improve current casting quality, reduce manufacturing costs and explore new markets for the process. Optimisation of the mechanical and physical properties of the cerami...
Benoit Nemery - One of the best experts on this subject based on the ideXlab platform.
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Airborne polyvinyl alcohol (PVA) and cellulose Fibre levels in Fibre-cement factories in seven European countries
The Annals of occupational hygiene, 2001Co-Authors: Hilde De Raeve, Joris Van Cleemput, Benoit NemeryAbstract:Abstract Because of their relatively high diameter, polyvinyl alcohol (PVA) Fibres, as used in Fibre-cement, are not Fibres as defined by WHO (or other) regulations. Nevertheless, as with all particulate raw materials, it can be questioned if and to what extent particles with critical fibrous dimensions might be generated by the handling or machining of this material. In order to investigate any tendency of PVA Fibres to release airborne particles with critical fibrous dimensions (WHO Fibres), static and/or personal samples were taken in eight Fibre-cement factories at locations where potential exposures to PVA Fibres were expected to be the highest. The following locations were surveyed: the PVA Fibre weighing station, where PVA bales are opened mechanically and the PVA Fibres are dispersed and weighed in a dry state; the Fibre-cement slate punching machine; the slate ‘riven edge’ cutting machine or sheet sawing machine, whichever was present in the respective factories. Since cellulose Fibres are an important constituent of Fibre-cement, the Organic Fibre concentrations observed at the machining operations include cellulose. At each factory a control sample was taken in open air. Sampling, sample preparation and sample analysis by scanning electron microscopy (SEM) were performed according to standard German procedures. Only very low number concentrations of Organic WHO Fibres, ranging from below detection limit to 0.006 f/ml, were found. These levels are lower than the typical levels of Organic Fibres commonly found in the normal personal environment (0.009–0.02 f/ml), stemming from the release of particles by a person's activities and from clothing and other textiles (bed sheets, blankets, pillow,...). We conclude that the handling of PVA Fibres as well as the machining of PVA and cellulose Fibre containing cement products in the Fibre-cement factories surveyed have a low potential to release Fibres with critical fibrous (WHO) dimensions.