Three-dimensional Fiber Orientation of FRTP Obtained by Injection Molding —Detailed Analyses on the Fiber Orientation of a Thin Plate at the exit of a Pinpoint Gate—

Abstract

The detailed analyses were conducted on three-dimensional fiber orientation of thin FRTP plate with a pinpoint-gate at the center. To visualize the 3 D fiber orientation, X-ray transmission CT was used and the following conclusions were obtained.1) Owing to the change in flow direction from expanding flow in the filling stage to shear flow in the packing stage, the fiber orientation at the exit of the gate changes from concentric alignment to radial one.2) Molding conditions such as injection speed, mold temperature and resin temperature have slight influence on the fiber orientation.3) The development of shear flow is easily affected by plate thickness and gate dimension. Thinner plate thickness and smaller gate size bring about lower fiber orientation because of less shear flow development.