Method of forming reducing formation of impressions from the forming tool

US4948548A · kind A · utility

Assignee

• Rohm GmbH Chemische Fabrik · DE

Inventors

• Friedrich Hanstein · Groß-Zimmern, DE
• Karl-Heinz Fehring · Riedstadt, DE

Key dates

• Filing date: Mar 2, 1989
• Grant date: Aug 14, 1990
• Expiry date: Mar 2, 2009

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B29K2995/0022
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

In forming operations on plastic sheets, plates, strips, or tubes (particularly, having highly glossy surfaces) by molding or forming tools, the surface qualities, particularly the gloss, remains undamaged if; (a) the tool is maintained at a temperature in the thermoelastic state region of the plastic until disengagement of the plastic from the tool; and (b) the formed plastic is cooled at its rear side to below the softening temperature, and is disengaged from the forming tool while said tool is hot.