3D FINITE-ELEMENT METHOD FOR THE SIMULATION OF THE FILLING STAGE IN INJECTION-MOLDING

During the molding of industrial parts using injection molding, the mo lten polymer flows through converging and diverging sections as well a s in areas presenting thickness and flow direction changes. A good und erstanding of the flow behavior and thermal history is important in or der to optimize the part design and molding conditions. This is partic ularly true in the case of automotive and electronic applications wher e the coupled phenomena of fluid flow and heat transfer determine to a large extent the final properties of the part. This paper presents a 3D finite element model capable of predicting the velocity, pressure, and temperature fields, as well as the position of the flow fronts. Th e velocity and pressure fields are governed by the generalized Stokes equations. The fluid behavior is predicted through the Carreau Law and Arrhenius constitutive models. These equations are solved using a Gal erkin formulation. A mixed formulation is used to satisfy the continui ty equation. The tracking of the flow front is modeled by using a pseu do-concentration method and the model equations are solved using a Pet rov-Galerkin formulation. The validity of the method has been tested t hrough the analysis of the flow in simple geometries. Its practical re levance has been proven through the analysis of an industrial part.