Method and apparatus for forming plastic preforms for plastic containers with curve evaluation

An apparatus for forming plastic preforms into plastic containers comprising:

• at least one forming station which has a blow mould into which the plastic preform is introduced:
• an application device which applies the plastic preform with a flowable medium, wherein the plastic preform is applied with at least two different pressure levels;
• a stretching bar which is introduced into the plastic preform to expand the plastic preform in its longitudinal direction, wherein a pressure curve and/or a movement curve of the stretching bar and/or a force curve of the stretching bar is determined by a measuring device during the expansion process;
• a processor device which is configured for evaluating at least one of the curves and for determining at least one point or region of the curve, which is characteristic of a course of the curve;
• and
• a plurality of forming stations and a control device controlling the forming stations by taking the at least one point and region into account to form plastic preforms into the plastic containers, wherein
• data are linked to each point and/or region, which allow conclusions to be drawn about the relevant forming station.