Method for producing a vessel from a preform, with feedback depending on the expansion end point of the preform

摘要

A method for producing a vessel (2), involving: placing a preform (3) into the mold; at the pre-blowing cue (tp), controlling the opening of an electrovalve (22) for establishing communication between the preform (3) and a source (20) of gas at a predetermined pre-blowing pressure (Pp); measuring the pressure (P) inside the preform (3); at the blowing cue (tS), controlling the opening of an electrovalve (26) for establishing a communication between the preform (3) and a source (24) of a gas at a blowing pressure (PS) higher than the pre-blowing pressure (Pp); memorising the variations of the pressure (P) inside the preform (3) at least during the interval between the pre-blowing cue (tp) and the blowing cue (tS); detecting the expansion end moment (tC) from which the pressure in the preform (3) increases in a linear manner; and advancing the blowing cue (tS) according to the expansion end moment (tC).