hollow body blow molding extrusion head with a preform wall thickness distribution system and method for controlling the wall thickness of a preform

摘要

extrusion head for hollow body blow molding with a preform wall thickness distribution system. an extrusion head (1) for hollow body blow molding comprising: a body (2) and a power plug (3) disposed within the body to define a cylindrical span (4) through which it can be flow plastic material fed by an extruder; an opening (6) of the die disposed at the bottom end of the body (2); and a bottom portion (30) of the power plug (3) disposed within the die opening (6) to define a cylindrical span (10) in communication with said cylindrical span (4) for the outlet of the tubular preform. said extrusion head; and a plunger (20) supporting at the bottom an oval-shaped graft (40) being slidably mounted within the chamber (32) formed on said bottom portion (30) of the power plug. the piston may move from a retracted resting position in which the bottom edge (48) of the oval-shaped graft is within said chamber (32) of the bottom portion of the power plug to a distended operating position in the wherein the bottom edge (48) of said oval-shaped graft protrudes at the bottom with respect to the bottom edge (38) of said bottom portion of the power plug.