Stretch-blowing method and machine

摘要

A method for stretch-blowing containers of preforms in a blow-molding station of a blow-molding machine, where a stretching bar is adjusted during a stretching process via an electric servomotor by taking along the preform bottom until it contacts a mold cavity bottom of a blow mold, and where in the final phase or at the end or after termination of the stretching process the force transmitted by the servomotor to the stretching bar is reduced in a controlled manner by a maximum force. A stretch-blowing machine, including an electronic programmable control unit having an input section for programming a fixed or a variable reduction of the force the servomotor transmitted in a final phase or upon termination or after termination of each stretching process to the stretching bar with regard to a maximum force and a fixed or a variable period of time for the force reduction and/or a fixed or a variable force reduction waiting time.

主权项

1. A method for stretch-blowing containers of preforms in a blow-molding station of a blow-molding machine, wherein at least one blow mold defines a mold cavity, comprising:
providing in the blow-molding station a blast nozzle and a stretching bar which can be adjusted via an electric servomotor controlling one of at least the speed, the force, the distance, and a combination thereof of the stretching bar adjustment with an electronic control unit via the servomotor for each stretching process, adjusting the stretching bar during the stretching process by pressurizing the preform from the blast nozzle while taking along the preform bottom to the maximum of contact of the bottom with the mold cavity bottom, and reducing the force the servomotor transmits to the stretching bar in a controlled manner with regard to a maximum force one of in a final phase, at the end, or after termination of the stretching process, wherein the force is controlled for a period a corresponding to a rotary angle region of an entire revolution of a blow wheel drivable in a rotatable manner and including the blow mold.