Study of polymer melt flow in sequential injection molding process

Chen, S. C.; Chen, N. T.; Hsu, K. S.; Hsu, K. F.

doi:10.1002/aic.690420622

Cited by 13 publications

(10 citation statements)

References 14 publications

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“…Figure 7 shows velocity vectors of polymer melts on the x À y plane. It can be clearly seen that the velocity around the inner corners (green circles) is greater than for other corners (red circles), which is in accordance with the results of Chen et al [3] The velocity vectors and the temperature distributions of polymer melts are shown together in Figure 8. It can be seen that the temperatures around the inner corners are higher than for other corners.…”

Section: Validation: Scim Of a Cavity With A Block Insertsupporting

confidence: 88%

Three‐dimensional modelling and simulation of sequential co‐injection moulding with application to a toothbrush handle

Liu

Ouyang

et al. 2016

Can J Chem Eng

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Sequential co‐injection moulding (SCIM) is a promising technique in industrial production. Because of the complex hydrodynamic effect of air on polymer melts in a moulding process, it is difficult to accurately design and control the process. Corresponding theoretical investigations are very limited, especially for the transient free surface flows in the filling stage. In this paper, a three‐dimensional (3‐D) unified model is proposed for simulating fluids flow in SCIM. The melted polymer and air in the cavity can be regarded as a continuous fluid. The evolution of the melt front interface and skin/core melt interface are captured simultaneously at any moment by the level set method; this method has been widely‐used in two‐phase flow for its ability to track interfaces. The finite volume method is combined with a domain extension technique to deal with 3‐D flows in an irregular cavity. The model is validated by simulating the SCIM process for a cavity with a block insert, and a distinct corner effect is observed. For a widely‐used plastic toothbrush made by SCIM, the evolutions of transient free surfaces in the filling stage are investigated. All numerical results are consistent with corresponding experimental results, and demonstrate the capability of the model with the domain extension technique to simulate multiphase flows in SCIM.

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Section: Validation: Scim Of a Cavity With A Block Insertsupporting

confidence: 88%

Three‐dimensional modelling and simulation of sequential co‐injection moulding with application to a toothbrush handle

Liu

Ouyang

et al. 2016

Can J Chem Eng

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“…The successful predictions of 374 Brought to you by | Purdue University Libraries Authenticated Download Date | 6/14/15 12:57 PMcurved melt flow front patterns and more symmetrical flow evolution with respect to the cavity centerline at lower values of runner-to-gate diameter ratio demonstrate a very good agreement with the instantaneous filling patterns of polymer melt flow obtained from the experimental study ofChen et al (1996). .…”

supporting

confidence: 65%

“…Since the standard applications of the present fluid flow solver does not provide a very complete solution of polymer melt flow in simulating injection molding process (due to numerical restrictions in changes of viscosity, compressibility and moving interface), a more reliable numerical model, which introduces user defined functions (macros written in C++ programming language) into the present standard VOF formulation to account for the changes in viscosity, density and air-melt flow interface, is developed. The capabilities of the proposed numerical model in simulating mold insert injection molding processes are then assessed in comparison with the experimental data (Behrens, 1983;Chen et al, 1996) As summarized in Table 4, filling stage of mold insert injection molding is simulated with different mesh resolutions, geometric dimensions (runnerto-gate diameter ratios) and phase change effects. A set of three different gate diameters, ranging from 0.5 mm to 0.75 mm, are used for a pre-selected runner diameter of 2 mm to study effects of runner-to-gate diameter ratios The capability of the proposed numerical methodology for predicting basic flow features such as evolution of melt flow front shape, 3-D effects, fountain flow, and curved shape of polymer melt flow front are initially verified with the experimental data and Moldflow MPI 3-D model as illustrated in Figures.…”

Section: Resultsmentioning

confidence: 99%

Injection Molding Simulation of a Compressible Polymer

Tutar¹,

Karakus²

2009

Journal of Polymer Engineering

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This study presents the 3-D simulation solutions for mold insert polymer injection molding process. A more complete and robust numerical approach is developed by considering the effects of solidification, compressibility and viscosity changes for high-viscous non-isothermal polymer melt flow conditions. The generated user-defined functions are successfully incorporated into a volume of fluid (VOF) method, which is coupled with a finite volume approach, to represent a more realistic poljmer melt flow simulations. Λ comprehensive high-resolution differencing scheme (CICSAM) is successfully adopted to capture the moving interface. The comparative numerical results demonstrate that the present numerical approach improves the accuracy of simulation predictions of 3-D compressible mold filling process and can be used with a confidence in simulating real molding flow conditions.

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“…Modeling of the coinjection‐molding process is a relatively recent undertaking. A few numerical simulations of the coinjection‐molding process have been attempted 9–24. All these efforts were based on the use of the Hele–Shaw approximation to predict the interface evolution between the skin and core materials during filling for sequential coinjection, with the exception of Lee et.…”

Section: Introductionmentioning

confidence: 99%

“…Also, no detailed explanation of this residence time approach was given in their articles 12–16. Chen et al17–19 also developed a simulation program. Theirs was based on a dual‐filling‐parameter particle‐tracing scheme employed within each grid layer in the gapwise direction to trace the advance of the melt fronts for both the skin and core materials during the sequential coinjection process.…”

Section: Introductionmentioning

confidence: 99%

Interface development and encapsulation in simultaneous coinjection molding. I. Two‐dimensional modeling and formulation

Li¹,

Isayev²

2003

J of Applied Polymer Sci

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ABSTRACT:In the coinjection-molding process two polymers are injected into a mold sequentially or simultaneously. During the process one polymer melt forms the skin and the other forms the core, resulting in an encapsulated sandwich structure. In an attempt to develop a process model and simulation of simultaneous coinjection molding, along with the interface treatment a theoretical approach, physical model, and numerical algorithm were formulated based on the Hele-Shaw approximation. A detailed picture of the dynamics and kinematics of the interface evolution, providing a description of the multilayer flow and interface development during the multicomponent injection-molding process, information typically lacking in the available literature, is systematically presented. Based on the developed numerical simulation code, the moldability of various material combinations can be evaluated, which is required for process optimization.

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Study of polymer melt flow in sequential injection molding process

Cited by 13 publications

References 14 publications

Three‐dimensional modelling and simulation of sequential co‐injection moulding with application to a toothbrush handle

Three‐dimensional modelling and simulation of sequential co‐injection moulding with application to a toothbrush handle

Injection Molding Simulation of a Compressible Polymer

Interface development and encapsulation in simultaneous coinjection molding. I. Two‐dimensional modeling and formulation

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