• Advances in Computational Design
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• v.5 no.2
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• pp.111-125
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• 2020

The flow behavior of polymer melts within a slit die is an important consideration when designing a die geometry. The quality of the extruded polymer product can be determined through an evaluation of the flow homogeneity, wall shear rate and pressure drop across the central height of the die. However, mathematical formulations cannot fully determine the behavior of the flow due to the complex nature of fluid dynamics and the nonlinear physical properties of the polymer melts. This paper examines two slit die geometries in terms of outlet velocity uniformity, shear rate uniformity at the walls and pressure drop by using the licensed computational fluid dynamics package, Ansys POLYFLOW, based on the finite element method. The Carreau-Yasuda viscosity model was used for the rheological properties of the polypropylene. Comparative analysis of the simulation results will conclude that the modified die design performs better in all three aspects providing uniform exit velocity, uniform wall shear rates, and lower pressure drop.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.4
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• pp.36-44
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• 2020

This study analyzed the deformation behavior of the high density polyethylene (HDPE) bottle in the blow molding process. We carried out finite element (FE) simulations using ANSYS Polyflow. First, the axisymmetric model was executed by 2D FE-simulation to determine the change of bottle wall thickness during the molding process. Then, the square model of the bottle was executed by 3D FE-simulation to gauge the effects of gas pressure on the change of wall thickness. The experiment results showed that the FE-simulations were able to upgrade the quality of the HDPE bottle in the blow molding process. These results can be used as guidance in adjusting gas pressure, as well as be extended for further study to determine process parameters such as temperatures, forming velocity, parison shape, etc.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.34-41
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• 2021

Interventional radiology and minimally invasive surgery both require a precisely shaped microcatheter. Microcatheters are manufactured using polymer extrusion processes with a die and puller. The manufacturing parameters and die geometry greatly influence the profile of the extrudate and designing dies using a trial-and-error process is expensive and requires a lot of time. Therefore, predicting the profile of the extrudate is important for manufacturing microcatheters. This study investigates the effects of die design and geometry on the profile of the extrudate. The profiles of the extrudate are predicted using ANSYS Polyflow with respect to the different die geometries. The outer and inner diameters and wall thickness of the predicted extrudate are compared to those of a target extrudate. The die swell of melt polymer and the effect of the pulling are both examined. Optimized die designs are suggested for manufacturing the target extrudate.