This graph gives the fiber orientation parameter a 11 at several distances from the gate for a rectangular plaque molded from nylon. The shell-core structure is evident at all three locations. This graph is a summary plot of the shell orientation for polycarbonate, nylon, and PBT plaques for a two second fill time.
All materials exhibit roughly the same orientation in the shell.
This graph shows the core orientations for the three materials. Notice that the PC and PBT core orientations are close to random, while the nylon plaque shows a more transverse orientation in the core. This graph shows the effect of fill time in the shell for a PBT plaque. Lengthening the fill time has essentially no effect on fiber orientation in the shell. This graph shows the effect of fill time in the shell for a PBT plaque.