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从事异形材挤出的人员都知道,在异形材挤出成形时,设计异形挤出模是一件非常困难的事情。在设计这类挤出模时,必须具有丰富的成形加工经验和熟练的设计技巧.从模具中挤出的异形材,由于熔料在模具内的复杂流动,纤维会形成与模腔形状不同的异形形状。熔料在模具内的复杂流动是由局部模腔的剪切速度不同而造成的。作为非牛顿流体的塑料熔融物,将因局部剪切速度差异而导致熔料局部形状的差异.特别是当剪切速率的比值增大时,表示不同位置剪切速率的异形形状,将形成与模腔不同形状的挤出件。如果熔料在模具内以栓流动,则可将由剪切速率引起的形状差异减至最少。可挤出与模
People who are engaged in profile extrusion know that it is a very difficult task to design a profile extrusion die in the extrusion of profiled materials. In the design of this type of extrusion die, you must have a wealth of experience in forming and processing skills and design skills extrusion from the mold profiled material, due to the complex flow of melt in the mold, the fiber will form a different cavity shape Alien shape. The complicated flow of the melt in the mold is caused by the different shear rates of the partial cavity. As the plastic melt of non-Newtonian fluid, the local shape of the melt will be different due to the difference of the local shear rate, especially when the ratio of the shear rate increases, the deformed shape representing the shear rate at different positions will form Different shapes of the cavity extrusion. If the melt flows in the mold as a plug, the difference in shape caused by the shear rate can be minimized. Can be extruded and die