Blow moulding machine with variable intermediate pressure level

A method for shaping plastics material pre-forms into plastics material containers, wherein the plastics material pre-forms are introduced into a blow mould and are expanded to form the plastic bottles by being acted upon with a gaseous medium in the blow mould, comprising the steps of:

• a preliminary blow moulding by acting upon the plastics material pre-forms with a first pressure;
• an intermediate blow moulding of the plastics material pre-forms at a second pressure which is higher than the first pressure;
• and
• a final blow moulding of the plastics material pre-forms at a third pressure which is higher than the second pressure,
• wherein
• at least the second pressure is varied during a working, and
• wherein the blow moulds are conveyed along a pre-set conveying path during the expansion of the plastics material pre-forms and the second pressure is selected in a manner dependent upon a position of the blow moulds along this conveying path.