Abstract: According to the Folgar-Tucker model, full 3D simulation of injection filling behavior and fiber orientations were studied for a sample of 15% short glass fiber reinforced polyamide 6 with a convex cross section. It showed that full 3D technology could simulate effectively filling behavior and the fountain effect of injection molding. The fiber orientation in the skin was parallel to shearing flow, and the degree of fiber orientation in the sample's big end was lower than in the small end. The fiber orientation of 3D solid was complex along the three axes. In the x direction, the degree of fiber orientation increased at first then decreased with increasing the filling length. Along the y axis, the degree of fiber orientation in the sample's small end increased gradually with increasing distance to the core, but the degree of fiber orientation in the big end increased at first then decreased. Along the direction of z axis, the degree of fiber orientation in the sample's small end tended to increase from core to skin, while that was reducing gradually in the big end.

Key words: injection molding, polyamide 6, filling, orientation, convex cross section, simulation, glass fiber