一新型多流道片材机头的几何设计及计算方法

Geometry Design and Calculation of a Novel Multi-flow Channel Sheeting Die

提出一种新型的能够保证熔体在口模出口处速度及压力均匀分布的片材机头.机头的全部流道由等长的不等间距放置的平直板条组成,全部流道中在熔体特征黏度相等的假定条件下,给出用栅条构成的阻流栅通道宽度的算法及其相关计算公式.例举挤出1 m宽板材的算例,而且计算结果表明熔体沿幅宽的平均停留时间分布的均匀性远高于其它型片材机头.

A new type sheeting die which can guarantee the polymer fluid get the even velocity and pressure distribution at the mold export was put forward. All flow channels in the die were constituted by straight and even laths which were placed asymmetry. Based on the assumption that characteristic viscosity of the melt in all flow channels was equal, the algorithm to determine the width of the flow channels formed by the straight strips and relative expression were given. Moreover, calculation results show that the profile of residence time distribution of polymer melt across the die width was better than that of other type dies.