METHOD FOR PRODUCING A VESSEL FROM A PREFORM, WITH FEEDBACK DEPENDING ON THE DEVELOPMENT POINT OF THE PREFORM

摘要

Method for producing a vessel (1) by stretch blow-moulding in a mould (11) from a preform (3) made of plastic material, comprising the operations consisting inheating the preform (3) to a predetermined heating temperature (T);introducing the preform (3) in the mould (11);stretching the preform (3) by means of a rod (16) displaced at a predetermined stretching speed (V_E);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 (P_P) and a pre-blowing flow rate (D_P);measuring the pressure (P) inside the preform (3);detecting a pressure peak;memorising the moment (t_B) at which this pressure peak occurs as well as the corresponding pressure (P_B) inside the preform (3);comparing the moment (t_B) and the pressure (P_B) of the peak detected with, respectively, a predetermined moment and pressure for a theoretical pressure peak;if the measured peak and the theoretical peak are not confounded, modify at least one of the following parameters: pre-blowing pressure (P_P), pre-blowing flow rate (D_P), pre-blowing cue (t_P), stretching speed (V_E), heating temperature (T).