基于数值分析的轮胎胶料共挤出口模设计

Design of Tire Compounds Coextrusion Die Based on Numerical Simulation

在轮胎胶料挤出生产中,口模的结构对共挤出产品的质量起着关键的作用,但在实际生产中,共挤出口模的设计主要依靠经验,口模设计质量的控制需要经过多次试模和修模。采用流体计算软件Polyflow进行轮胎胶料(TWD40/FS10)的共挤成型过程的三维数值模拟,分析共挤出过程中的速度、压力分布以及胶料熔体的流动情况,并通过试验验证模拟的可行性。针对初始口模设计的不足,提出增加窄缝区域高度和扩充口模入口的方法,有效解决初始模具设计中速度分布不均的问题,改善了口模中熔体的流动,提高了挤出质量,同时还降低了挤出过程中的能耗。利用数值方法可对共挤出口模结构进行设计,提出的口模设计方法可以对同类轮胎胶料共挤出口模结构的设计提供指导。

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.