Method for the manufacture of thin-walled shaped articles of thermoplastic material

US4039609A · kind A · utility

Assignee

• Bellaplast GmbH · DE

Inventors

• Alfons W. Thiel · Mainz, DE
• Hans Hell · Wiesbaden, DE

Key dates

• Filing date: Aug 24, 1976
• Grant date: Aug 2, 1977
• Expiry date: Aug 24, 1996

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B29K2995/0096
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

Thin-walled articles of thermoplastic material are formed in a continuous method and apparatus starting with heating and extruding granular thermoplastic raw material in the form of a continuous web which is immediately stabilized by rapid cooling of its opposite surfaces and the stabilized web wherein the material sandwiched between the precooled outer surface layers remains at or near extrusion temperature is fed into a thermal forming station wherein shaping tools form the articles in the web without the need for further heating of the web. Adjustments are provided for correlating the cooling action to different materials and web feed rates, for varying the web feed rates and increments, and for varying the shaping tool movements to adapt for different materials and sizes of articles. After the formed articles are separated from the web the web residue is fed back to be mixed with incoming raw material at the extrusion station.