A special screw for blow molding machines capable of using powder resin is made of high-quality alloy steel 38CrMoAl, and consists of a feed section, a compression section and a metering section. The helix of the feed section is of variable pitch and variable depth with a helix length of 5–7 pitches; the helix of the compression section is of constant pitch and variable depth with a helix length of 8–10 pitches; the helix of the metering section is of constant pitch and constant depth with a helix length of 10–12 pitches. The outer diameter of the flight gradually increases along the screw, and the outer diameter of the flight at the rearmost end of the metering section is 1–2 mm larger than that at the foremost end of the feed section. By adjusting screw technical parameters and performance indicators such as increasing compression ratio, prolonging plasticization time, adjusting screw speed and changing screw length-diameter ratio, the screw can directly use powder resin mixture as raw material to produce high-quality PVC blow-molded fresh-keeping films for fruits and vegetables. Single-screw extrusion equipment equipped with this screw has been widely used in the production of PVC blow-molded fresh-keeping films.
Area Code: CN
Application Number: CN200710058176.2
