A 3-DIMENSIONAL BOUNDARY-ELEMENT APPROACH TO GAS-ASSISTED INJECTION-MOLDING

An Eulerian boundary-element approach is implemented for the three-dim ensional simulation of the primary gas penetration stage of the gas-as sisted injection molding process. The fluid is assumed to be viscous, Newtonian and incompressible. The formation of a solid skin layer due to cooling is neglected. The evolution of the melt front and gas/melt interface is obtained on the basis of mass conservation as the melt fl ows through a fixed (three-dimensional) mesh of the cavity. At each ti me step, the boundary integral equations are solved over the two front surfaces and part of the cavity walls surrounding the melt region. Th e front tracking technique combined with an effective boundary-element scheme appears to be quite efficient for handling complex three-dimen sional geometries. The method and its potential are illustrated throug h examples from two- and three-dimensional simple flows.