异型材存在内应力是造成型材变形的根本原因.为了减少变形 ,我们从型材截面设计、模具设计、挤出工艺以及型材存放等方面分析了塑料异型材产生内应力的根本原因 ,并给出减少内应力的方法.“,”The internal stress phenomenon that exists in iso_shape is the fundamental reason,which can deformate the iso_shape.In order to reduce the deformation,we analyse the fundamental reason about the cross section design,mold_design,extrusion technology and store of iso_shape and so on,which can make the iso_shape produce internal stress,and advice the way of reducing the internal stress.