Design of Tire Compounds Coextrusion Die Based on Numerical Simulation

Abstract

The structure of extrusion die plays a crucial role in the quality control of tire compounds profile production. But in practice, the design of coextrusion die is mainly dependent on the experience of the designer, thus many times of modifications and experiments are needed to gain an acceptable product. The three-dimensional coextrusion mold process for tire compounds(TWD40/FS10) is analyzed by using the computational fluid dynamics(CFD) package polyflow. The outlet velocity and extrusion pressure as well as the flow process are analyzed in details, and the reliability of the simulation is verified by experiment. With the simulation results of the initial die design, a non-uniform velocity distribution is observed. To solve the problem of the non-uniform velocity distribution, two steps of the die design for the tire compounds coextrusion are proposed, including heighten and widen the narrow section of the die lip, which are beneficial to balance the outlet velocity and extrusion pressure as well as to get reasonable product. The results show that the die design method based on numerical simulation is valid and it is useful to provid guidelines for the die design of the similar kind profiles of tire compounds.