In reference to the wedge passage between the two slit parts, the double slit will be called convergent die in the following.
up to 1250 [s.sup.-1]) for Vectra B 950 in the convergent die for the part with [h.sub.1] = 0.5 mm (see Fig.
In this convergent die configuration, the melt flows first into the slit with [h.sub.1] = 0.5 mm, and the rigid polymer chains are aligned in flow direction.
The flow of convergent die at the upper stream region is the same as the straight die but the flow is going to be uniaxial near the die exit.
However, in the case of the convergent die, the model estimates the thickness swell larger than the experimental data.
The PTT model for the convergent die is relatively good.
The result of the convergent die is represented by Fig.
Ftrstly, the tendency of the K-BKZ model that the convergent die causes a larger swell in comparison with the divergent die does not change by adjusting the uniaxial elongational behavior by [Beta].
In this work, straight, divergent and convergent dies for blow molding were employed, and the numerical results were compared with the experimental ones for HDPE.
The output rate was 5 kg/hr, and the apparent shear rates on the wall at the exits were estimated to be 32.5 [s.sup.-1], 32.5 [s.sup.-1] and 65.0 [s.sup.-1] for the straight, divergent and convergent dies, respectively.