Cross-flowMinimization Method (CFMM)
The profile die module functions based onan assumption that the undesired cross-flows inside the die are suppressed asmuch as possible. 异形材模头模块基于模头横向流动最小化的假设A direct consequence of this assumption一个直接的推论是 is that each cross-section on thedie must be balanced.在模头上的每一个截面必须平衡 In other words换句话说this means that the appropriate amount of the material flows through eachcross-section.这意味着适当数量的材料流过每一横截面 假设在模头流道内只有一个主导的
流动方向(挤出方向),完全没有(或忽略)其他方向的流动,料流的分布由垂直于挤出方向的一系列横截面所决定。If this assumption is satisfied, the 2D+1D approach can be used andthe balancing procedure becomes relatively very simple, straightforward andefficient,如果假定成立,一维流动假设方法的使用,平衡过程变得相对简单,直截了当和有效 since the 2D+1D approach is used, 由于一维流动假设方法的使用the flow on each cross-section is not influenced by the previouscross-sections. 每一个横截面的流动不受前一截面的影响In reality, 实际上sincethe previous cross-section is balanced,由于前一横截面被平衡it delivers just the desired amount of the material for eachpart of the balanced cross-section. 它传递平衡横截面的每一部分刚好数量的材料This is the reason why this simplified method can be appliedquantitatively for balanced dies only. 这就是简化方法可以使用的原因
模头的每一横截面又被细分为许多部分(可以是用分隔片实际隔开,也可以是虚拟的挤出方向的投影图中心线分开),然后通过对横截面几何尺寸的调整,使得横截面上各部分的料流流量在模头总流量中的百分比与该部分相对应的部分型材的面积在型材横截面总面积中的百分比相同。