1) because of its advantages in aspects of the environmental protection (poison-less), installation and construction, large caliber HDPE water-supply pipe is the first choice for the outdoor service pipes. People lay greater importance on them in the old pipe repair and urban water supply systems; 2) this production line adopts the efficient single-screw extruders with specially designed shielded type BM screws in order to ensure the thorough melting of the matter, thus vigorously enhances the extrusion volume; 3) the die adapter utilizes the lately designed basket type nose or the spiral divided headpiece, it may produce the double-ply anti-ageing environmental protection model buried water-supply pipelines; 4) planet cutting section smoothing, chamfered standardization, dust-collecting device may fulfill the non-scraps cutting.