Vacuum sizing die adopts spiral structure, the structure form is in reference to the German barton technology, the company absorb commissioning in the process of practice experience and my company's old customer feedback problems, on the basis of many improvements were made by my company's professional and technical personnel, to abandon the disadvantages of the previous die structure and reach the various polyolefins can apply to new and old plastic and reduced the extrusion pressure, uniform plasticizing, high speed extrusion stability, tubing the indicators meet the national standards. The structure is a new olefin composite type, with uniform wall thickness, smooth inside and outside, no bump or scar, more stable setting and more accurate size.