METHOD FOR PRODUCING VESSELS WITH FEEDBACK DEPENDING ON THE PRE-BLOWING STARTING POINT

摘要

The invention relates to a method for producing a vessel (2) by blowing in a mould (11) from a preform (3) made of a plastic material, comprising the following steps : placing the preform (3) into the mould; at a predetermined moment, called pre-blowing cue (t_P), controlling the opening of an electrovalve (22) for establishing a communication between the inside of the preform (3) and a source (20) of gas at a predetermined pre-blowing pressure; measuring the pressure (P) inside the preform (3); detecting the so-called real moment (t_A) of the beginning of the pre-blowing at which the pressure (P) in the preform (3) starts to increase; comparing the moment (t_A) with a theoretical pre-blowing beginning moment; if the real moment (t_A) of the pre-blowing beginning is later than the theoretical pre-blowing beginning moment, advance the pre-blowing cue (t_P); if the real moment (t_A) of the pre-blowing beginning is earlier than the theoretical pre-blowing beginning moment, delay the pre-blowing cue (t_P).