Apparatus for the production of an injection molded part

US4738613A · kind A · utility

Assignee

• Krauss-Mafei AG · DE

Inventors

• Martin Eichlseder · Tettenweis, DE
• Ingo Preuss · Munich, DE

Key dates

• Filing date: Jul 25, 1986
• Grant date: Apr 19, 1988
• Expiry date: Jul 25, 2006

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S425/81
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

A injection molded part of thermoplastic material, in particular an information carrier disk, is produced by cutting and removal of a sprue part from the injection molded part. The sprue removal leaves an opening in the injection molded part. In order to obtain a clean and smooth opening surface with a fit diameter that is as accurate as possible, the sprue part is axially offset relative to the injection molded part so that the integral connection between these two parts extends only over a part of the opening. The diameter of the axially projecting part is equal to or larger than the diameter of the opening and the rest of the opening being produced by injection molding. The dimensions are advantageously chosen so that a parting edge inclined at an angle of 45.degree. to the plane of the opening is formed and that the injection molded part amounts to 70% and the part to be separated to 30% of the length of the open. The injection molded length of the opening may also be variable. The sprue part may be cut from the injection molded part and removed, either in the closed or open state of the injection molding tool.