Approaches for Numerical Modeling and Simulation of the Filling Phase in Injection Molding: A Review

Abstract

Injection molding is a multiphase process that requires accurate simulation of the filling phase. This is a key element in predicting the complete injection molding cycle. The filling phase presents a complex set of challenges, including migrating melt fronts, multi-phase flow, non-Newtonian fluid dynamics, and intertwined heat transfer. Evolving from 1D to 2D, 2.5D, and 3D techniques, filling simulation research has adapted to capture the intricacies of injection-molded parts. However, the need for accuracy in the characterization of the rheological properties of polymers during filling is still of paramount importance. In order to systematically categorize the numerical methods used to simulate the filling phase of injection molding, this review paper provides a comprehensive summary. Particular emphasis is given to the complex interaction of multiple geometric parameters that significantly influence the dynamic evolution of the filling process. In addition, a spectrum of rheological models is thoroughly and exhaustively explored in the manuscript. These models serve as basic mathematical constructs to help describe the complex viscous behavior of polymers during the filling phase. These models cover a spectrum of complexity and include widely recognized formulations such as the Power-Law, second-order, Herschel–Bulkley, Carreau, Bird–Carreau, and Cross models. The paper presents their implementation to include the temperature-dependent influence on viscosity. In this context, the extensions of these models are explained in detail. These extensions are designed to take into account the dynamic viscosity changes caused by the different thermal conditions during the filling process. An important contribution of this study is the systematic classification of these models. This categorization encompasses both academic research and practical integration into commercial software frameworks. In addition to the theoretical importance of these models, their practical value in overcoming challenges in the field of injection molding is emphasized. By systematically outlining these models within a structured framework, this classification promotes a comprehensive understanding of their intrinsic characteristics and relevance in different scenarios.

Reprocessing Possibilities of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)–Hemp Fiber Composites Regarding the Material and Product Quality

“…Very often, in practice and in scientific work, special rheological models are used to extrapolate viscosity values to shear rate areas for which no experimental tests have been carried out [ 55 , 69 , 70 ]. The experimentally obtained viscosity curves were extrapolated using the Cross–WLF (Cross-Williams–Landel–Ferry) model [ 71 , 72 ]: where:…”

Rheological Behavior Features of Feedstocks with a Two-Component Wax–Polyolefin Binder Compared to Analogs Based on Polyoxymethylene

“…Currently, many papers regularly publish study results on the rheological properties of feedstocks and polymers used in them [8][9][10]. New reviews and articles devoted to the issues of modeling the molding process based on rheological data continue to appear [11][12][13]. In summary, feedstocks are highly filled composite materials molded in the state of sus-pension, which, depending on the degree of filling, is characterized by a yield point.…”

“…In summary, feedstocks are highly filled composite materials molded in the state of sus-pension, which, depending on the degree of filling, is characterized by a yield point. Many rheological equations describe the rheological state of such materials, which are detailed in [12]. Table 1 presents the most popular of these rheological equations for reference.…”