The main machine of this line is a single screw plastic extruder of new type and high efficient. According to the property of processing plastic, the screw structure chooses some new types of mix units. It has optimal plasticity effects and high production capability. The barrel adopts new style notch machine trunk, with high extrusive volume. It also can adopt computerized control or normal regulations control according to customers' requirements and the operation is convenient. Extruder die adapter can fulfill low pressure extrusion, thus increases tubing's quality.