The Experts below are selected from a list of 756 Experts worldwide ranked by ideXlab platform
Weng-sing Hwang - One of the best experts on this subject based on the ideXlab platform.
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Development of an interactive simulation system for the determination of the Pressure–time relationship during the filling in a Low Pressure Casting process
Science and Technology of Advanced Materials, 2001Co-Authors: Weng-sing HwangAbstract:An interactive computer simulation system has been developed in this study to aid the determination of the Pressure–time relationship during the filling of a Low Pressure Casting to eliminate filling-related defects while maintaining its productivity. The Pressure required to fill a Casting in a Low Pressure Casting process can be separated into two stages. The first stage is to exert Pressure to force the molten metal to rise in the riser tube up to the gate of the Casting die, which varies from Casting to Casting due to the drop of the level of the molten metal in the furnace, whilst the second stage is to add an additional Pressure to push the molten metal into the die cavity in a way that will not cause much turbulence and have the proper filling pattern to avoid the entrapment of gas while maintaining productivity.One of the major efforts in this study is to modify the filling simulation system with the capability to directly predict the occurrence of gas porosity developed earlier to interactively determine the proper gate velocity for each and every part of the Casting. The Pressure required to fill the die cavity can then be obtained from the simulations.The operation principles and the interactive analysis system developed are then tested on an automotive wheel made by the Low Pressure Casting process to demonstrate how the system can aid in determining the proper Pressure–time relations, the p–t curve, required to produce a sound Casting without sacrificing productivity.
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development of an interactive simulation system for the determination of the Pressure time relationship during the filling in a Low Pressure Casting process
Science and Technology of Advanced Materials, 2001Co-Authors: Weng-sing HwangAbstract:An interactive computer simulation system has been developed in this study to aid the determination of the Pressure–time relationship during the filling of a Low Pressure Casting to eliminate filling-related defects while maintaining its productivity. The Pressure required to fill a Casting in a Low Pressure Casting process can be separated into two stages. The first stage is to exert Pressure to force the molten metal to rise in the riser tube up to the gate of the Casting die, which varies from Casting to Casting due to the drop of the level of the molten metal in the furnace, whilst the second stage is to add an additional Pressure to push the molten metal into the die cavity in a way that will not cause much turbulence and have the proper filling pattern to avoid the entrapment of gas while maintaining productivity.One of the major efforts in this study is to modify the filling simulation system with the capability to directly predict the occurrence of gas porosity developed earlier to interactively determine the proper gate velocity for each and every part of the Casting. The Pressure required to fill the die cavity can then be obtained from the simulations.The operation principles and the interactive analysis system developed are then tested on an automotive wheel made by the Low Pressure Casting process to demonstrate how the system can aid in determining the proper Pressure–time relations, the p–t curve, required to produce a sound Casting without sacrificing productivity.
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Development of an interactive simulation system for the determination of the Pressure-time relationship during the filling in a Low Pressure Casting process
Science and Technology of Advanced Materials, 2001Co-Authors: Jer-haur Kuo, Feng Lin Hsu, Weng-sing HwangAbstract:An interactive computer simulation system has been developed in this study to aid the determination of the Pressure-time relationship during the filling of a Low Pressure Casting to eliminate filling-related defects while maintaining its productivity. The Pressure required to fill a Casting in a Low Pressure Casting process can be separated into two stages. The first stage is to exert Pressure to force the molten metal to rise in the riser tube up to the gate of the Casting die, which varies from Casting to Casting due to the drop of the level of the molten metal in the furnace, whilst the second stage is to add an additional Pressure to push the molten metal into the die cavity in a way that will not cause much turbulence and have the proper filling pattern to avoid the entrapment of gas while maintaining productivity. One of the major efforts in this study is to modify the filling simulation system with the capability to directly predict the occurrence of gas porosity developed earlier to interactively determine the proper gate velocity for each and every part of the Casting. The Pressure required to fill the die cavity can then be obtained from the simulations. The operation principles and the interactive analysis system developed are then tested on an automotive wheel made by the Low Pressure Casting process to demonstrate how the system can aid in determining the proper Pressure-time relations, the p-t curve, required to produce a sound Casting without sacrificing productivity. © 2001 Elsevier Science Ltd. All rights reserved.
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Development of an interactive simulation system for die cavity filling and its application to the operation of a Low-Pressure Casting process
Modelling and Simulation in Materials Science and Engineering, 2000Co-Authors: Weng-sing HwangAbstract:The purpose of this study is to develop an interactive die filling simulation system to assist in the design and operation of a Low-Pressure Casting process. One of the keys to the success for the design and operation of the Low-Pressure Casting process is to obtain an optimal pressurization curve in order to avoid fLow related defects while maintaining productivity. The simulation system developed is based on the incorporation of a computational fluid dynamics technique, named SOLA-MAC, which has the capability of treating transient fluid fLow problems with free surfaces. The analytical system with the necessary pre-processing and post-processing modules is loaded on a personal computer. The accuracy and reliability of the filling simulation system is then verified by water model experiments, which are also conducted in this study. The capability of directly predicting fLow related defects such as gas/dross entrapment during the transient filling stage by using an air particle method is added to the simulation system. It is also made interactive by alLowing the Casting engineer to view the transient filling pattern and the corresponding gas entrapment situation on the computer screen, interrupt the execution of the program, change the Casting operation and restart the program from a previous instant. A process design algorithm is also proposed in this study, such that the Casting is divided into several parts depending on their geometric characteristics and performance requirements. By taking advantage of the interactive capability of the system, the proper gate velocity to fill each and every part of the cast can be determined. In turn, the necessary pressurization curve can be determined. The developed system is tested on an automotive wheel cast made by a Low-Pressure Casting process. The Casting is divided into three distinctive parts. The proper gate velocity to fill each part is interactively determined by directly examining the filling pattern and its resultant gas entrapment condition. With the optimal combination of the gate velocity, the pressurization curve for the whole filling stage can be obtained. It is found that the pressurization curve for the variable gate velocity shows only small deviation from that of employing a constant gate velocity throughout the whole filling stage. It is consistent with the general knowledge in the Low-Pressure Casting industry: that the Casting quality is rather sensitive to the pressurization curve employed in the process.
Xuanpu Dong - One of the best experts on this subject based on the ideXlab platform.
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a new shell Casting process based on expendable pattern with vacuum and Low Pressure Casting for aluminum and magnesium alloys
The International Journal of Advanced Manufacturing Technology, 2010Co-Authors: Wenming Jiang, Xuanpu Dong, Defeng Liao, Zhong ZhaoAbstract:A new shell Casting process, with the adoption of the foam pattern of lost foam Casting (LFC) as prototype and the combination of the thin shell fabrication technology of investment Casting and vacuum and Low-Pressure Casting process, was proposed for manufacturing complicated and thin-walled aluminum and magnesium alloy precision Castings. Loose-sand uniting vacuum was used in the new process to further reinforce the thin shell, and the new process proves to be a process with simple process, Low cost, and high thin shell strength. Because the molten metal filling and solidification are completed under air Pressure and vacuum level, the filling capability and feeding capacity of the molten metal are greatly improved, and the Castings become denser. This paper mainly investigated the fabrication technology of thin shell based on foam pattern prototype, the removing foam and roasting shell process and vacuum and Low-Pressure Casting process. The few-layer compound thin shell of silica sol–sodium silicate was adopted for the new process. Removing foam pattern was carried out at 250°C for 30 min, and the shell was roasted at 800°C for 1 h. Combined with the vacuum and Low-Pressure Casting process, this new shell Casting process has successfully produced thin wall and complex aluminum and magnesium alloy parts with high quality. In addition, comparisons in terms of filling ability, microstructure, mechanical properties, porosity, and surface roughness among this new shell Casting, gravity Casting, and LFC were also made to show the characterization of this new shell Casting process.
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A new shell Casting process based on expendable pattern with vacuum and Low-Pressure Casting for aluminum and magnesium alloys
International Journal of Advanced Manufacturing Technology, 2010Co-Authors: Wenming Jiang, Xuanpu Dong, D F Liao, Zitian Fan, Zhong ZhaoAbstract:A new shell Casting process, with the adoption of the foam pattern of lost foam Casting (LFC) as prototype and the combination of the thin shell fabrication technology of investment Casting and vacuum and Low-Pressure Casting process, was proposed for manufacturing complicated and thin-walled aluminum and magnesium alloy precision Castings. Loose-sand uniting vacuum was used in the new process to further reinforce the thin shell, and the new process proves to be a process with simple process, Low cost, and high thin shell strength. Because the molten metal filling and solidification are completed under air Pressure and vacuum level, the filling capability and feeding capacity of the molten metal are greatly improved, and the Castings become denser. This paper mainly investigated the fabrication technology of thin shell based on foam pattern prototype, the removing foam and roasting shell process and vacuum and Low-Pressure Casting process. The few-layer compound thin shell of silica sol-sodium silicate was adopted for the new process. Removing foam pattern was carried out at 250A degrees C for 30 min, and the shell was roasted at 800A degrees C for 1 h. Combined with the vacuum and Low-Pressure Casting process, this new shell Casting process has successfully produced thin wall and complex aluminum and magnesium alloy parts with high quality. In addition, comparisons in terms of filling ability, microstructure, mechanical properties, porosity, and surface roughness among this new shell Casting, gravity Casting, and LFC were also made to show the characterization of this new shell Casting process.
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Mold-Filling Characteristics of AZ91 Magnesium Alloy in the Low-Pressure Expendable Pattern Casting Process
Journal of Materials Engineering and Performance, 2005Co-Authors: Hebao Wu, Xuanpu Dong, Zitian Fan, N Y Huang, X.F. TianAbstract:The magnesium (Mg) alloy Low-Pressure expendable pattern Casting (EPC) process is a newly developed Casting technique combining the advantages of both EPC and Low-Pressure Casting. In this article, metal filling and the effect of the fLow quantity of inert gas on the filling rate in the Low-Pressure EPC process are investigated. The results showed that the molten Mg alloy filled the mold cavity with a convex front laminar fLow and the metal-filling rate increased significantly with increasing fLow quantity when fLow quantity was beLow a critical value. However, once the fLow quantity exceeded a critical value, the filling rate increased slightly. The influence of the fLow quantity of inert gas on melt-filling rate reveals that the mold fill is controlled by fLow quantity for a Lower filling rate, and, subsequently, controlled by the evaporation of polystyrene and the evaporation products for higher metal velocity. Meanwhile, the ex-perimental results showed that the melt-filling rate significantly affected the fLow profile, and the filling procedure for the Mg alloy in the Low-Pressure EPC process. A sLower melt-filling rate could lead to misrun defects, whereas a higher filling rate results in folds, blisters, and porosity. The optimized filling rate with Mg alloy Casting is 140 to 170 mm/s in Low-Pressure EPC.
Zhong Zhao - One of the best experts on this subject based on the ideXlab platform.
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a new shell Casting process based on expendable pattern with vacuum and Low Pressure Casting for aluminum and magnesium alloys
The International Journal of Advanced Manufacturing Technology, 2010Co-Authors: Wenming Jiang, Xuanpu Dong, Defeng Liao, Zhong ZhaoAbstract:A new shell Casting process, with the adoption of the foam pattern of lost foam Casting (LFC) as prototype and the combination of the thin shell fabrication technology of investment Casting and vacuum and Low-Pressure Casting process, was proposed for manufacturing complicated and thin-walled aluminum and magnesium alloy precision Castings. Loose-sand uniting vacuum was used in the new process to further reinforce the thin shell, and the new process proves to be a process with simple process, Low cost, and high thin shell strength. Because the molten metal filling and solidification are completed under air Pressure and vacuum level, the filling capability and feeding capacity of the molten metal are greatly improved, and the Castings become denser. This paper mainly investigated the fabrication technology of thin shell based on foam pattern prototype, the removing foam and roasting shell process and vacuum and Low-Pressure Casting process. The few-layer compound thin shell of silica sol–sodium silicate was adopted for the new process. Removing foam pattern was carried out at 250°C for 30 min, and the shell was roasted at 800°C for 1 h. Combined with the vacuum and Low-Pressure Casting process, this new shell Casting process has successfully produced thin wall and complex aluminum and magnesium alloy parts with high quality. In addition, comparisons in terms of filling ability, microstructure, mechanical properties, porosity, and surface roughness among this new shell Casting, gravity Casting, and LFC were also made to show the characterization of this new shell Casting process.
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A new shell Casting process based on expendable pattern with vacuum and Low-Pressure Casting for aluminum and magnesium alloys
International Journal of Advanced Manufacturing Technology, 2010Co-Authors: Wenming Jiang, Xuanpu Dong, D F Liao, Zitian Fan, Zhong ZhaoAbstract:A new shell Casting process, with the adoption of the foam pattern of lost foam Casting (LFC) as prototype and the combination of the thin shell fabrication technology of investment Casting and vacuum and Low-Pressure Casting process, was proposed for manufacturing complicated and thin-walled aluminum and magnesium alloy precision Castings. Loose-sand uniting vacuum was used in the new process to further reinforce the thin shell, and the new process proves to be a process with simple process, Low cost, and high thin shell strength. Because the molten metal filling and solidification are completed under air Pressure and vacuum level, the filling capability and feeding capacity of the molten metal are greatly improved, and the Castings become denser. This paper mainly investigated the fabrication technology of thin shell based on foam pattern prototype, the removing foam and roasting shell process and vacuum and Low-Pressure Casting process. The few-layer compound thin shell of silica sol-sodium silicate was adopted for the new process. Removing foam pattern was carried out at 250A degrees C for 30 min, and the shell was roasted at 800A degrees C for 1 h. Combined with the vacuum and Low-Pressure Casting process, this new shell Casting process has successfully produced thin wall and complex aluminum and magnesium alloy parts with high quality. In addition, comparisons in terms of filling ability, microstructure, mechanical properties, porosity, and surface roughness among this new shell Casting, gravity Casting, and LFC were also made to show the characterization of this new shell Casting process.
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Hydraulic simulation of filling process in Low Pressure
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys, 2007Co-Authors: Zhong Zhao, Yimin Gao, Hong ZhangAbstract:Effects of processing parameters on filling process in Low Pressure Casting have been investigated by hydraulic simulation. It was revealed that with increasing the Pressure-applying rate, the fluctuation of liquid surface is increased, while it is decreased with increasing the dynamical viscosity. In addition, with increasing the applying-Pressure rate, the lifting-delay time of liquid surface can be raised regardless of how large of area of exhausted-pipe line. Increasing the anti-Pressure in the cavity area and exhausted-pipe line section would extend the lifting-delay time of liquid surface, however, the very small section area is obviously detriment of filling process.
Mohamed El Mansori - One of the best experts on this subject based on the ideXlab platform.
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Geometrical effects on filling dynamics in Low Pressure Casting of light alloys
Journal of Manufacturing Processes, 2019Co-Authors: Marie Bedel, A. Sanitas, Mohamed El MansoriAbstract:Abstract In aluminum Low-Pressure sand Casting process, filling oscillations are observed when the metal front reaches a section change in a part. The effect of geometry on the filling oscillations is primary considered experimentally, including both mold cavity and filling system geometries. To highlight the geometric parameters impacting the oscillations, the pressurized melt fLow is secondly studied numerically and analytically. A new analytical model of oscillation is developed to quantitatively predict the oscillations. It links the resulting filling velocity to both the Low-Pressure Casting parameters and the mold cavity geometry. Considering oxides inclusion criterion from Casting literature, new rules to avoid bi-films defects are recommended for making reliable Low-Pressure Castings.
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Investigating surface roughness of ZE41 magnesium alloy cast by Low-Pressure sand Casting process
The International Journal of Advanced Manufacturing Technology, 2017Co-Authors: A. Sanitas, Marie Bedel, Nicolas Coniglio, Mohamed El MansoriAbstract:The sand mold 3D printing technologies enable the manufacturing of molds with great dimensional accuracy. However, the roughness of as-cast components is higher when cast in a 3D printed mold rather than in a traditional sand mold. Coating the inner cavity is an efficient solution but can be costly and, in the narrowest cavities, not achievable. Finding a procedure to reduce the as-cast roughness without coating would ease the Casting procedures. In the present work, surface analysis of ZE41 magnesium alloy is presented after being cast in 3D printed furan sand molds without coating using the Low-Pressure Casting process. The molten metal temperature was measured during Casting at different positions along the cast cavity. The as-cast surface roughness was correlated to the molten metal temperature and solid fraction at the time of contact against the sand mold surface.
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Investigating surface roughness of ZE41 magnesium alloy cast by Low-Pressure sand Casting process
International Journal of Advanced Manufacturing Technology, 2017Co-Authors: A. Sanitas, Marie Bedel, Nicolas Coniglio, Mohamed El MansoriAbstract:© 2017, Springer-Verlag London. The sand mold 3D printing technologies enable the manufacturing of molds with great dimensional accuracy. However, the roughness of as-cast components is higher when cast in a 3D printed mold rather than in a traditional sand mold. Coating the inner cavity is an efficient solution but can be costly and, in the narrowest cavities, not achievable. Finding a procedure to reduce the as-cast roughness without coating would ease the Casting procedures. In the present work, surface analysis of ZE41 magnesium alloy is presented after being cast in 3D printed furan sand molds without coating using the Low-Pressure Casting process. The molten metal temperature was measured during Casting at different positions along the cast cavity. The as-cast surface roughness was correlated to the molten metal temperature and solid fraction at the time of contact against the sand mold surface.
Dawei Zheng - One of the best experts on this subject based on the ideXlab platform.
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Study on Low-Pressure Casting Technique and Mold Design of the Aluminum Wheel
2019 IEEE International Conference on Mechatronics and Automation (ICMA), 2019Co-Authors: Jiaze Wang, Qingchun Zheng, Kaijie Lu, Pai Peng, Cong Chen, Jiehe Li, Peixin Li, Dawei ZhengAbstract:It is necessary to optimize the die structure for the Low-Pressure Casting of aluminum alloy wheel hub which is prone to shrinkage cavity and porosity. This paper simulated the mold filling and solidification process when the change of the temperature field and stress field, based on the solidification mold defect factors in central composite experiment and response surface analysis to optimize method, finally complete the multi-objective optimization using the algorithm of the NSGA-I reasonably come to the abrasive wall thickness values. In terms of experimental verification, the phase structure of aluminum alloy Casting was observed to be uniform and smooth without shrinkage cavity and porosity, which realized the lightweight design of the die and improved the quality of the die Casting.
