Machine and process for moulding by stretching and blowing

摘要

Machine for the production of receptacles of plastic. A stretching rod (32) is displaced by actuating means (69) comprising a servo-motor (72) whose operation is controlled by a controller installation (73) by means of an adjustment loop (75). The blowing air is introduced into the preform via a servo-valve (60) whose operation is also controlled by this installation (73) by means of an adjustment loop (76) which can be combined with the first adjustment loop (75). It is thus possible to control in a precise manner the process of transformation of a preform into a receptacle by means of curves of stretching and pressure increase. Calibration operations of the maximum path of the stretching rod as a function of the length of the mould cavities and calibration operations of the path of positioning of the stretching rod as a function of the preform can be carried out easily and in an automated fashion, thereby ensuring excellent safety of production and very high adaptability to all conditions of production.