Computer design aids for non-axis-symmetric profile dies

A new design is proposed to correct the flow imbalance and its experimental performance is compared with the simulation. Behavior of resins with opposing extremes of melt elasticity are contrasted with model predictions. Limits of applicability for commonly used modeling simplifications are examined. The initial results suggest that the model is reasonably accurate in predicting the unbalanced behavior of the die. The calculated and experimentally measured velocity ratios differ by only 30 to 35 percent. This agreement is excellent considering that the model does not take into account elastic effects and does not predict vortices in the entrance region to the profile. The measured and calculated pressure drops differ by approximately 30 percent. This difference is expected when elastic effects are neglected and entrance and exit pressure corrections are not applied.