CAE of Mold Cooling in Injection Molding Using a Three-Dimensional Numerical Simulation

Abstract

In recent years, increased attention has been paid to the design of cooling systems in injection molding, as it became clear that cooling affects both productivity and part quality. In order to systematically improve the performance of a cooling system in terms of rapid, uniform, and even cooling, the designer needs a CAE analysis tool. For this, a computer simulation has been developed for three-dimensional mold heat transfer during the cooling stage of an injection molding process. In this simulation, mold heat transfer is considered as cyclic-steady, three-dimensional conduction; heat transfer within the melt region is treated as transient, one-dimensional conduction; heat exchange between the cooling channel surfaces and coolant is treated as steady, as is heat exchange with the ambient air and mold exterior surfaces. Numerical implementation includes the application of a hybrid scheme consisting of a modified three-dimensional, boundary-element method for the mold region and a finite-difference method with a variable mesh for the melt region. These two analyses are iteratively coupled so as to match the temperature and heat flux at the mold-melt interface. Using an example, the usefulness of the simulation developed here in the design of a cooling system for an injection molding process is amply demonstrated.

Associative feature modeling for concurrent engineering integration

“…Technically, if the cooling channels are modeled in this associative feature form, CAE analysis for cooling effect evaluation can be easily integrated because the cooling guiding path can be used as the circuit mesh [19]. For example, those logical rules that are connected with mold design CAE analysis in [25,27,28] can be implemented with certain query and execution methods.…”

“…However, when potential geometrical collision between cooling channels and other features being checked, 3D cooling channel geometry must be considered. For cooling effect analysis, CAE tools also require cooling circuit mesh representation [19]. This paper uses cooling channels as the illustration case; its associative nature will be introduced in detail in the following sections.…”

“…In this case, because each circuit is designed mainly to cover one impression, therefore the cooling effect can be better controlled to satisfy heat-transfer requirements. This is especially recommended for complex moldings where the cooling effect analysis has been carried out with some simulation packages [19,28].…”

“…Certain geometrical entities are grouped with specific characteristics. These entity groups can be identified as core and cavity inserts [17], sub-inserts and electrode [18], cooling channels [19,20], and machining set-ups [21]. Let us analyze such geometrical entities briefly.…”

“…However, this system was not integrated with a CAD system; initial design parameters are input by the user via a command line interface. Wang and his co-workers [19,28] had developed a computer-aided mold design system. They suggested a design strategy with three-stages, initial design with one-dimensional (1D) approximation, two-dimensional design with optimization, and three-dimensional design with cooling effect analysis.…”