Injection Molding Simulation of a Compressible Polymer

Abstract

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.

Solidification behavior of high‐density polyethylene during injection molding process: Enthalpy transformation method

“…As one of the widely used fabricating techniques of polymers, injection molding accounts for over 1/3 of all plastics processed in modern industry. Computer‐aided engineering (CAE) technology has found wide application in material selection, mold design, analysis of the part defects as well as optimization of the processing parameters for injection molding 4–7. Attention has been attracted to investigate the heat transfer during the injection moldings of crystalline polymers since early 1990s,8–10 because the quality and performance of molded parts depend heavily on the selection of operational variables11–15 during the molding process, especially in the cooling period.…”

Numerical study of polymer melt flow in a three-dimensional sudden expansion: viscous dissipation effects

“…Early numerical studies [1][2][3][4] analyzing the injection molding process of polymer melt flow using simplified two-dimensional (2-D) approximations of Hele-Shaw [5] were later extended to 3-D numerical polymer melt flow solutions in the thick cavities with varying thickness dimensions, to obtain more complete simulation solutions [6][7][8][9].…”

“…Tutar and Karakus [8,9] conducted a series of numerical studies in which 3-D flow front development of the polymer melt flow was successfully reproduced in the mold cavity of varying dimensions, by considering the effects of compressibility and viscosity variations on non-Newtonian fluid flow. In these numerical studies, the viscosity changes were expressed in terms of strain rate, temperature and pressure by using modified Cross constitutive equations [10], while density changes were expressed in terms of temperature and pressure by using the modified Tait equation of state [11] during the injection molding.…”

Computational Modeling of the Effects of Viscous Dissipation on Polymer Melt Flow Behavior During Injection Molding Process in Plane Channels

“…Since eariy numerical studies [15][16][17][18], which propose more simplified two-dimensional (2D) Hele-Shaw approximation [19] to simulate polymer melt flow, are valid only for thin channels and mold cavities, the recent numerical studies [20][21][22] are now extended to three-dimensional (3D) solutions for a better representation of polymer melt flow in thick cavities and channels. Tutar and Karakus [22,23] conduct a finite volume method based 3D numerical simulations to represent a more complete solution of thermal flow characteristics of polymer melt flow in mold cavity with variable dimensions. In their numerical studies, the viscosity changes are successfully represented as a function of strain rate, temperature, and pressure by using modified Cross type equations [24], while density changes are represented as a function of pressure and density by using modified Tait equations [25] in the injection molding process of polymer melt flow.…”

“…The present study now aims at extending previous finite volume method computational efforts [22,23] for solution of polymer melt flow in injection molding to more complete simulation solutions for predicting/resolving viscous dissipation effects on the local thermal and velocity conditions of the non-Newtonian fluid in a plane channel by considering the viscosity and density variations in the flow for different velocity and temperature boundary and geometric conditions. More sophisticated/elaborated mathematical formulations for describing the rhelogical phenomena involved ensures more complete and robust numerical simulation solutions for highly viscous, compressible and high shear flows under varying temperature and velocity boundary conditions.…”