Numerical Prediction of Flake Orientation and Surface Color in Injection Molding of Flake-Pigmented Thermoplastics

The present study attempts to develop physical modeling and numerical simulation system for prediction of the surface color in injection molding of flake-pigmented thermoplastic composites. Folgar-Tucker model along with the orientation tensor is employed to predict the orientation state of pigment flakes. A phenomenological relationship between the orientation state and the surface color is proposed to estimate the surface color and color defects from the orientation prediction result. Basic studies are carried out using simple geometries with a hole or rib structure. Also a qualitative comparison between the numerical prediction and the experimental result is carried out for a complex geometry having ribs and holes. The color defects such as flow marks and weld lines could be reasonably predicted using the developed modeling and simulation system. POLYM. COMPOS., 32:1297-1303, 2011. (C) 2011 Society of Plastics Engineers