The Experts below are selected from a list of 3564 Experts worldwide ranked by ideXlab platform
L. Iuliano - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of inserts for modular thermoplastic injection moulds produced by Spin Casting
Journal of Materials Processing Technology, 2001Co-Authors: Andrea Gatto, L. IulianoAbstract:Abstract Concurrent engineering enables a company to speed up its time to market: rapid prototyping forms a part of this approach. The term rapid tooling (RT) refers to the rapid creation of tools in much the same way as RP means the rapid creation of models. It is a method that offers both designers and manufacturers attractive advantages in the form of time compression and cost reduction. In an era of automated manufacturing the prototype can be produced layer by layer directly from a 3D CAD model using rapid prototyping (RP) techniques [Rapid prototyping and manufacturing, fundamental of stereolithography, SME, Dearborn, MI, 1992; Layer Manufacturing a Challenge of the Future, Tapir Publisher, Trondheim, Norway, 1992]. The drawback is that only a limited number of RP technologies cater for metal parts and taking the top three positions of vendors into account (Stratasys, 3D Systems, Sanders), their systems have no access to metal prototypes [Rapid prototyping, state of the industry report 1998, SME, Dearborn, MI, 1999]. Several RT techniques can be employed to save time in the manufacturing of plastic injection moulds: thermal spraying; quick Casting, electroplating, direct metal sintering. These techniques have been subject to intensive study for a number of years and their extensive commercial potential makes them attractive propositions. Major advances in technology makes Spin Casting a fully proven tool for manufacturing and prototyping functional components. This paper describes the employment of Spin Casting for the construction of mould inserts in standard, commercial-grade pressure die Casting zinc.
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Evaluation of inserts for modular thermoplastic injection moulds produced by Spin Casting
Journal of Materials Processing Technology, 2001Co-Authors: Andrea Gatto, L. IulianoAbstract:Abstract Concurrent engineering enables a company to speed up its time to market: rapid prototyping forms a part of this approach. The term rapid tooling (RT) refers to the rapid creation of tools in much the same way as RP means the rapid creation of models. It is a method that offers both designers and manufacturers attractive advantages in the form of time compression and cost reduction. In an era of automated manufacturing the prototype can be produced layer by layer directly from a 3D CAD model using rapid prototyping (RP) techniques [Rapid prototyping and manufacturing, fundamental of stereolithography, SME, Dearborn, MI, 1992; Layer Manufacturing a Challenge of the Future, Tapir Publisher, Trondheim, Norway, 1992]. The drawback is that only a limited number of RP technologies cater for metal parts and taking the top three positions of vendors into account (Stratasys, 3D Systems, Sanders), their systems have no access to metal prototypes [Rapid prototyping, state of the industry report 1998, SME, Dearborn, MI, 1999]. Several RT techniques can be employed to save time in the manufacturing of plastic injection moulds: thermal spraying; quick Casting, electroplating, direct metal sintering. These techniques have been subject to intensive study for a number of years and their extensive commercial potential makes them attractive propositions. Major advances in technology makes Spin Casting a fully proven tool for manufacturing and prototyping functional components. This paper describes the employment of Spin Casting for the construction of mould inserts in standard, commercial-grade pressure die Casting zinc.
G.d. Jordaan - One of the best experts on this subject based on the ideXlab platform.
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Thermal process and novel control methods for Spin-Casting
Journal for new generation sciences, 2006Co-Authors: Z. Huan, G.d. JordaanAbstract:The quality of Spin Casting products and mould life are critically dependent on thermal conditions they undergo. In order to improve the performance of production and to optimise the Spin-Casting process, characteristics of the thermal process was firstly identified by means of the measurement and simulation. Furthermore the investigation of the developed control methods, including the thermal property substitute method and mixture method of the metal powder, was kept on the effect of air-cooling induced automatically from the Spinning of the mould on the thermal process. The air cooling system was developed to optimise the thermal process during Casting, utilising a theoretical analysis of the air-flow characteristics in a cooling tube submerged in a silicon mould and the characteristics of convection heat transfer associated with the mould and cast part. A numerical simulation of the Casting process was also adopted in the analysis. The effect of the developed system on the thermal process was determined experimentally and it was found that a system of aircooling, automatically induced from the Spinning of the mould, is feasible in optimisation of the thermal process. The developed control methods can be applied to the practice of Spin Casting individually or collectively according to the specific situations and requirements.
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Air-cooling induced from Spinning of Spin-Casting moulds
Applied Thermal Engineering, 2004Co-Authors: Zhongjie Huan, G.d. JordaanAbstract:The quality of Spin cast products and mould life are critically dependent on the thermal conditions they are exposed to. An investigation was carried out on the effect of air-cooling induced by the Spinning of the mould and its consequences on the thermal process. A system was developed to optimise the thermal process during Casting, utilising a theoretical analysis of the air-flow characteristics in a cooling tube submerged in a silicon mould and the characteristics of convection heat transfer associated with the mould and cast part. A numerical simulation of the Casting process was also used in this process. The effect of the developed system on the thermal process was determined experimentally and it was found that a system of air-cooling, automatically induced from the Spinning of the mould, is feasible in optimization of the thermal process.
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Galerkin finite element analysis of Spin Casting cooling process
Applied Thermal Engineering, 2004Co-Authors: Zhongjie Huan, G.d. JordaanAbstract:A Galerkin finite element numerical model was established to analyse the cooling process for Spin Casting mould and cast parts, to predict the solidification time for functional parts with different shapes and mould temperature distribution at different manufacturing conditions, and to investigate the effects of different cooling methods as well as the cooling parameters on the cooling process. A computer program was developed for this purpose and it was proved that the established numerical model is effective to simulate the Spin Casting process with accuracy, acceptable stability and convergence. The results obtained show that some factors, such as the clamping time, intensity of convection heat transfer, the use of a mould processing-table with a metal surface are important factors affecting the solidification time and cooling process. In addition, it was determined that the mixing of copper powder or other metals with a high thermal conductivity and specific heat, with the silicone rubber material in an appropriate composition before vulcanising, can be effective in controlling and optimising the cooling process.
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Investigation of the cooling of Spin-Casting moulds
Applied Thermal Engineering, 2003Co-Authors: Zhongjie Huan, G.d. JordaanAbstract:Abstract Spin Casting is being used widely in the prototyping industry as a secondary process to convert a master model into a functional metal or plastic part. The main problem of the Spin-Casting process is the poor thermal conductivity of silicone rubber as mould material––which leads to a long cooling time between Casting processes, a short lifespan of the mould and therefore quality problems with respect to the final product. In order to address these problems different cooling methods, such as the λ – ρC method and latent heat storage method, have been developed, investigated experimentally and described in this paper. Experimental results show that some metals––such as plain carbon steel––can be used to control the thermal process in Spin Casting effectively.
Andrea Gatto - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of inserts for modular thermoplastic injection moulds produced by Spin Casting
Journal of Materials Processing Technology, 2001Co-Authors: Andrea Gatto, L. IulianoAbstract:Abstract Concurrent engineering enables a company to speed up its time to market: rapid prototyping forms a part of this approach. The term rapid tooling (RT) refers to the rapid creation of tools in much the same way as RP means the rapid creation of models. It is a method that offers both designers and manufacturers attractive advantages in the form of time compression and cost reduction. In an era of automated manufacturing the prototype can be produced layer by layer directly from a 3D CAD model using rapid prototyping (RP) techniques [Rapid prototyping and manufacturing, fundamental of stereolithography, SME, Dearborn, MI, 1992; Layer Manufacturing a Challenge of the Future, Tapir Publisher, Trondheim, Norway, 1992]. The drawback is that only a limited number of RP technologies cater for metal parts and taking the top three positions of vendors into account (Stratasys, 3D Systems, Sanders), their systems have no access to metal prototypes [Rapid prototyping, state of the industry report 1998, SME, Dearborn, MI, 1999]. Several RT techniques can be employed to save time in the manufacturing of plastic injection moulds: thermal spraying; quick Casting, electroplating, direct metal sintering. These techniques have been subject to intensive study for a number of years and their extensive commercial potential makes them attractive propositions. Major advances in technology makes Spin Casting a fully proven tool for manufacturing and prototyping functional components. This paper describes the employment of Spin Casting for the construction of mould inserts in standard, commercial-grade pressure die Casting zinc.
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Evaluation of inserts for modular thermoplastic injection moulds produced by Spin Casting
Journal of Materials Processing Technology, 2001Co-Authors: Andrea Gatto, L. IulianoAbstract:Abstract Concurrent engineering enables a company to speed up its time to market: rapid prototyping forms a part of this approach. The term rapid tooling (RT) refers to the rapid creation of tools in much the same way as RP means the rapid creation of models. It is a method that offers both designers and manufacturers attractive advantages in the form of time compression and cost reduction. In an era of automated manufacturing the prototype can be produced layer by layer directly from a 3D CAD model using rapid prototyping (RP) techniques [Rapid prototyping and manufacturing, fundamental of stereolithography, SME, Dearborn, MI, 1992; Layer Manufacturing a Challenge of the Future, Tapir Publisher, Trondheim, Norway, 1992]. The drawback is that only a limited number of RP technologies cater for metal parts and taking the top three positions of vendors into account (Stratasys, 3D Systems, Sanders), their systems have no access to metal prototypes [Rapid prototyping, state of the industry report 1998, SME, Dearborn, MI, 1999]. Several RT techniques can be employed to save time in the manufacturing of plastic injection moulds: thermal spraying; quick Casting, electroplating, direct metal sintering. These techniques have been subject to intensive study for a number of years and their extensive commercial potential makes them attractive propositions. Major advances in technology makes Spin Casting a fully proven tool for manufacturing and prototyping functional components. This paper describes the employment of Spin Casting for the construction of mould inserts in standard, commercial-grade pressure die Casting zinc.
Hans Riegler - One of the best experts on this subject based on the ideXlab platform.
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Controlled Deposition of Nanosize and Microsize Particles by Spin-Casting
Langmuir : the ACS journal of surfaces and colloids, 2019Co-Authors: José Angél Danglad-flores, Karaneh Eftekhari, Andre G. Skirtach, Hans RieglerAbstract:The deposition of nanosize and microsize spherical particles on planar solid substrates by hydrodynamic-evaporative Spin-Casting is studied. The particles are dispersed in a volatile liquid, which evaporates during the process, and the particles are finally deposited on the substrate. Their coverage, Γ, depends on the processing parameters (concentration by weight, particles size, etc.). The behavior of the particles during the Spin-Casting process and their final Γ values are investigated. It is found that for up to particle diameters of a few micrometers, particle deposition can be described by a theoretical approach developed for the Spin-Casting of polymer solutions (Karpitschka, S.; Weber, C. M.; Riegler, H. Chem. Eng. Sci. 2015, 129, 243–248. Danglad-Flores, J.; Eickelmann, S.; Riegler, H. Chem. Eng. Sci. 2018, 179, 257–264). For large particles, this basic theory fails. The causes of this failure are analyzed, and a corrected, more general theoretical approach is presented. It takes into account pa...
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Deposition of polymer films by Spin Casting: A quantitative analysis
Chemical Engineering Science, 2018Co-Authors: José Angél Danglad-flores, Stephan Eickelmann, Hans RieglerAbstract:Abstract Spin Casting of mixtures of nonvolatile polymeric solutes dissolved in volatile solvents is studied experimentally and theoretically. The final solute coverage, time-resolved film thinning, time-resolved solvent evaporation, and evolution of the solute concentration within the thinning film is investigated for various combinations of different polymers (PMMA, PS, PS-b-PMMA) and different solvents (toluene, ethyl-acetate) for a wide range of polymer concentrations and Spin cast conditions. The comprehensive data unveil a clear picture of the Spin cast process. The findings are translated into a concise theoretical description. Easily available bulk properties of the solvent/solute mixture plus a single “calibration” experiment are sufficient for a quantitative description of the Spin cast process including a prediction of the final solute coverage. This and the well-specified boundary conditions render the approach useful for practical applications.
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Spin Casting of dilute solutions: Vertical composition profile during hydrodynamic-evaporative film thinning
Chemical Engineering Science, 2015Co-Authors: Stefan Karpitschka, Constans M. Weber, Hans RieglerAbstract:Abstract We analyze the vertical composition profile during hydrodynamic-evaporative film thinning (Spin Casting) of mixtures of non-volatile solutes and volatile solvents. We present a generic approach based on ideal solution behavior. Our analysis complements more detailed (but more system specific) studies that are available in the literature. The hydrodynamic-evaporative film thinning is described analytically based on the solvent properties. We find a universal film thinning behavior as a function of the rotation speed, viscosity and evaporation rate. The thinning process is uniquely characterized by its transition height i.e., the film thickness where hydrodynamics and evaporation contribute equally to film thinning. The theoretically predicted film thinning is in agreement with experimental results. The evolution of the internal film composition is calculated numerically. The numerical description is tractable and offers quantitative insights into the influence of the experimental conditions on the evolution of the internal composition. A characteristic Sherwood Number is introduced as a fundamental process parameter. It characterizes the vertical solution profile and serves as a well-defined and experimentally accessible criterion for the regimes of quantitative validity of our analysis. We also present new power laws, which link the process control parameters to the composition evolution, process duration, and final solute coverage. Because the analysis is generic and tractable, it also yields valuable insights for solutions behaving non-ideally.
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Physics of Spin Casting Dilute Solutions
arXiv: Fluid Dynamics, 2012Co-Authors: Stefan Karpitschka, Constans M. Weber, Hans RieglerAbstract:We analyze the evolution of the vertical composition profile during hydrodynamic-evaporative film thinning as it typically occurs during Spin Casting mixtures of non-volatile solutes and volatile solvents. We assume that the solvent dominates the hydrodynamic-evaporative film thinning. The internal spatio-temporal evolution of the composition is analyzed with a diffusive-advective approach. The analysis provides transparent physical insights into the influence of the experimental conditions on the evolution of the internal composition. We present power laws that link the process control parameters to the composition evolution, process duration, and final solute coverage. The analysis reveals a characteristic Sherwood Number as fundamental process parameter. It identifies for which stages of the process our analysis is quantitatively relevant and discloses the dominance of either diffusion or evaporation. The analysis is valid for dilute solutions e.g., for the deposition of solute (sub)monolayers. But it is also relevant for the deposition of thicker (polymer) films.
Gerrit Boschloo - One of the best experts on this subject based on the ideXlab platform.
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Effect of the Preparation Procedure on the Morphology of Thin TiO2 Films and Their Device Performance in Small-Molecule Bilayer Hybrid Solar Cells
ACS applied materials & interfaces, 2012Co-Authors: Eva L. Unger, F. Spadavecchia, Kazuteru Nonomura, Pål Palmgren, Giuseppe Cappelletti, Anders Hagfeldt, Erik M. J. Johansson, Gerrit BoschlooAbstract:Flat titanium dioxide films, to be used as the acceptor layer in bilayer hybrid solar cell devices, were prepared by spray-pyrolysis and by Spin-Casting. Both preparation methods resulted in anatase titania films with similar optical and electronic properties but considerably different film morphologies. Spray pyrolysis resulted in dense TiO2 films grown onto and affected by the surface roughness of the underlying conducting glass substrates. The Spin-Casting preparation procedure resulted in nanoporous titania films. Hybrid solar cell devices with varying layer thickness of the small-molecule semiconducting dye TDCV-TPA were investigated. Devices built with spray-pyrolyzed titania substrates yielded conversion efficiencies up to 0.47%. Spin-cast titania substrates exhibited short circuits for thin dye layer thickness. For thicker dye layers the performance of these devices was up to 0.6% due to the higher interfacial area for charge separation of these nanoporous TiO2 substrates.
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Spray-pyrolyzed vs Spin-cast titania films in bilayer hybrid solar cells with a small-molecular hole transporting dye
2012Co-Authors: Eva L. Unger, F. Spadavecchia, Kazuteru Nonomura, Pål Palmgren, Giuseppe Cappelletti, Anders Hagfeldt, Erik M. J. Johansson, Gerrit BoschlooAbstract:Titania films as acceptor layer in bilayer hybrid solar cell devices were prepared by spray-pyrolysis and by Spin-Casting. Both preparation methods resulted in anatase titania films with similar op ...