• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.1
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• pp.104-112
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• 1998

The mold filling process has been a central issue in the development of numerical methods to solve the casting processes. A mold filling which is inherently transient free surface fluid flow, is important because the quality of casting highly depends on such phenomenon, Most of the existing numerical schemes to solve mold filling process have severe limitations in time step restrictions or Courant criteria since explicit time integration is used. Therefore, a large computation time is required to analyze casting processes. In this study, the well known SOLA-VOF method has been modified implicitly to simulate the mold filling process. Solutions to example filling problems show that the proposed method is more efficient in computation time than the original SOLA -VOF method.

• Advanced Composite Materials
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• v.16 no.3
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• pp.207-221
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• 2007

The filling process of resin injection/compression molding (I/CM) can be divided into injection and compression phases. During the resin injection the mold is kept only partially closed and thus a gap is present between the reinforcements and the upper mold. The gap results in preferential flow path. After the gap is filled with the resin, the compression action initiates and forces the resin to penetrate into the fiber preform. In the present study, the resin flow in the gap is simplified by using the Stokes approximation, while Darcy's law is used to calculate the flow field in the fiber mats. Results show that most of the injected resins enter into the gap during the injection phase. The resin injection time is extremely short so the duration of the filling process is determined by the final closing action of the mold cavity. Compared with resin transfer molding (RTM), I/CM process can reduce the mold filling time or injection pressure significantly.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.1
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• pp.102-113
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• 2000

In this study, a three-dimensional gravity casting problem has been examined to investigate a coupled phenomenon of the filling and solidification process. This work simultaneously considers the two key phenomena of metal casting : the fluid flow during mold filling, and solidification process. The VOF method is used to analyze the free surface flow during filling and the equivalent specific heat method is employed to model the latent heat release during solidification. The time-implicit filling algorithm is applied to save the computational time for analyzing the mold filling process. The three-dimensional benchmark problem used in the MCWASP VII has been solved using both the implicit and explicit algorithm, and the present results are compared with the benchmark experimental results and the other numerical results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.36-41
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• 2015

In this paper, research on the mold design of motor housing produced by the HPDC process was conducted using computer simulations and experiments. Recently, automobile parts have been required to be light and have high strength. The die casting process was used to manufacture automotive motor housings. In the die casting process, the control of casting defects is very important. However, it has usually depended on the experience of the foundry engineer. For the analysis of the manufacturing process of motor housing, the finite element method is applied. Through the simulations using commercial software, the filling pattern and product defects could be confirmed. The analysis results obtained from the filling behavior of the casting process agreed with the experimental results. The computer simulation results of filling behavior were reflected in the optimal mold design of motor housing.

• Design & Manufacturing
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• v.7 no.1
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• pp.1-6
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• 2013

The injection molding process is a predominant method for producing plastic parts. In order to maximize productivity and molding quality in a injection mold, it is important that each cavity in a multi-cavity injection mold is identical. This requires that cavity dimensions should be identical and delivery system of melt to each cavity have to be the same. Despite the geometrically balanced layout in multi-cavity injection mold more than 4 cavities, it has been observed that the filling in each cavity results in imbalances. Most of cases, this phenomenon of filling imbalances have a bad effect on dimension accuracy, warpage, molding appearance and strength of molding parts. In this study, experiment were conducted to investigate the effect of filling imbalances on the molding quality(surface gloss, shrinkage, tensile strength) in the multy-cavity injection mold.

• Journal of Korea Foundry Society
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• v.24 no.4
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• pp.225-230
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• 2004

Computer simulation of mold filling and solidification has been performed in order to analyze the flow and solidification phenomena for the casting process of cylinder liner. The simulation result of mold filling shows that the molten metal flows into the mold in stable without scattering. The simulation results of solidification indicate that the last solidified area is located in the feeder. The temperature variation in casting is measured in actual casting and the result is compared with calculation result.

• Journal of Korea Foundry Society
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• v.36 no.5
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• pp.153-158
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• 2016

The lost foam casting process was used to fabricate Al-Si-Mg cast specimens, and the effects of the chemical composition and process variables on the tensile properties and the mold filling ability were investigated. Some porosity formation was observed in thick sections of the casting and better tensile properties were obtained for thin sections, presumably because of their lower porosity and the higher cooling rate. Tensile properties were not clearly enhanced by grain refining treatment with Ti; however, the elongation was significantly improved by Sr modification of the Al-Si-Mg alloy. The mold filling distance was generally proportional to the pouring temperature of the melt, and the distance was also increased by the addition of Ti.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.269-272
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• 2005

For the three decades, the mold-filling of injection molding process was modeled as Hele-Shaw model. However, this model can not consider the 3D effect. In this paper, numerical simulations of three dimensional mold-filling during the filling phase were performed. The governing equations were discretized by segregated finite element method, which used equal order interpolation for pressure and velocity fields. The iterative linear equation solver (JCG, SOR) was employed for the solution of the momentum and pressure equations. Volume of Fluid (VOF) was employed for the melt front advancement. To check the validity of the numerical results, the results were compared with the experimental ones. The agreements between the experiment and the numerical results were found to be satisfactory.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04a
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• pp.620-625
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• 1995

Finite element analysis tool was developed to analyze the casting process. Generally, casting processes consists of mold filling and solifification. In order to investigate the effects of process variables and to predict the defects, both filling and solidiffication process were simulated simultaneously. At filling process, especiallywe consider thermal coupling to investigate thermal history of material during the filling stage. And thermal condition at the final stage of filling is used as the initial conditions in a solidification process for the exact simulation of the actual casting processes. At mold filling process, Lagrangian-type finite element method with automatic remashing scheme was used to find the material flow. To avoid numerical instability in low viscous fluid, a perturbation method with artificial viscosity is adopted. At solififfication process, enthalpy-based finite element method was used to solve the heat transfer problem with phase change. And elastic stress analysis has been performed to predict the thermal residual stress. Through the FE analysis, solidiffication time, position of solidus line, liquidus line and thermal residual stress are studied. Finite element tools developed in this study will be used process design of casting process and maybe basic structure for total CAE system of castigs which will be constructed afterward.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.333-334
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• 2002

Injection-compression molding parts are many cases with complicated boundary condition which is difficult to analysis of mold characteristics precisely. In this study, the effects of various process parameters such as multi-point gate location, initial charge volume, injection time and pressure have been investigated using finite element method to fomulate the melt front advancement during the mold filling process. A general governing equation for tracking the filling process during injection-compression molding is applied to volume of fluid method. To verify the results of present analysis, they are compared with those of the other paper. The results show a strong effect of processing conditions as a result of variations in the three-dimensional complex geometry model.