Computer Simulation in Thermoplastic Injection Molding Takaaki Matsuoka Toyota Central Research and Development Laboratories, Inc. 41-1, Yokomichi, Nagakute, Aichi 480-11, Japan A package of computer programs has been developed for CAE (Computer Aided Engineering) in the injection molding of thermoplastics. It consists of mold cooling, polymer melt flow, fiber orientation, material properties, and stress analysis programs for 3 dimensional thin walled molded parts. They are integrated by using a common geometric model and are used to predict the quality of molds and molded parts at the stage of design. This article summarizes the theory and verified results of the polymer melt flow, fiber orientation, and material properties analyses associated with rheology. Key Words: Computer simulation/thermoplastic injection molding/polymer melt flow/ Fiber orientation/material properties
Fig.2 Schematic representation of a pressure profile in the cavity during injection molding. Fig.1 Integrated injection molding analysis programs. Fig.3 Definition of coordinate systems.
Fig.4 Flow chart for the flow analysis. Fig.5 Schematic representation of the geometry of a 4-ribbed square plate and its finite element model with triangular elements.
Table 1 Input data for flow analysis. Fig. 6 Calculated and experimental melt fronts.
Fig. 8 Planar fiber orientation and the orientation angle.
Fig.9 Laminated plate model of injection molded parts for the prediction of mechanical properties. Fig.10 Procedure of calculation of mechanical properties. Table 2 CombinationsofparametersM, Mm, Mf and A.
Vol.23 1995 Fig.11 Computed velocity distribution at the end of filling. Table 3 Mechanical properties of polypropylene and glass. Fig.12 Computed orientation parameters. Fig.13 Photograph of X-ray observation of metal fiber tracers in the square plate.
Fig.15 Predicted elastic moduli and thermal expansion coefficients in the square plate of 30 wt% GFPP. Fig.14 Predicted fiber distribution functions in the square plate of 30 wt% GFPP. The layers from Layer 1 to Layer 5 correspond to regions from surface to center in the thickness direction. Fig.16 Experimental elastic moduli and thermal expansion coefficients in the square plate of 30 wt% GFPP. Fig.17 Correlation plots between experimental and calculated results of elastic modulus and thermal expansion coefficient for the square plate of 30 wt% GFPP.
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