Controlling an extrusion blowing process

US4382761A · kind A · utility

Assignee

• Krupp Kautex Maschinenbau GmbH · DE

Inventors

• Werner Daubenbuchel · Bensberg, DE
• Dieter Hess · Rheinbach, DE

Key dates

• Filing date: Sep 29, 1980
• Grant date: May 10, 1983
• Expiry date: Sep 29, 2000

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B29C2948/92676
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

In extrusion blowing a hollow member, a preform is extruded and then blown in a mold to produce the final member. The weight of the hollow member is determined after its removal from the mold and compared to a reference value, thereby to adjust the size of the extrusion discharge opening to control the amount of material in the preform. The length of the preform is detected to control the movement of the mold thereby to keep a substantially constant length of extruded preform, while the time required to produce a preform is also maintained at a substantially constant value.