A.E. Varela V., J.M. Contreras L., J.S. Vargas L., and Z. Niño (Venezuela)
Simulation, thermoplastics, injection molding, finite elements.
The present work focuses on the prediction of temperature profiles in an injection-molding cavity. For this purpose, a computer program was developed for the solution of process models in partial differential equations, by the finite element method. This program allows the analysis of the effect of some operation variables on the temperature distribution, velocity, pressure, and shear rate of the cavity polymer during the injection process. The required data are the cavity dimensions, the melt temperature, the maximum cavity pressure, and coolant flow rate. For simulation, a rectangular cavity is employed that is divided into perpendicular segments across the cavity thickness and along the flow direction. Model equations include the differential equations of motion and energy, a modified Cross model for the viscosity, the Tait equation for the density, and empiric models for the thermal conductivity and specific heat. Program validation was carried out using temperature data of a previous experimental work. The resulting deviation percentage was from 6 to 10% for the surface temperature at two cavity locations in a cycle of polystyrene injection molding.
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