Methods and apparatus for flanging tubular polymer articles
US4559197A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1984 |
| Grant date | Dec 17, 1985 |
| Priority date | — |
| Expiry date | Jul 9, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/71
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method and apparatus are described for flanging a tubular article of a crystallizable thermoplastic polymer, particularly of a saturated linear polyester material such as polyethylene terephthalate, which has been heat-set to an elevated temperature, e.g. for producing bodies for processable food and beverage containers. The open end of the tubular body is applied to a flanging die and heated to a flanging temperature above the glass transition temperature but below the heat-set temperature of the polymer. The tubular body and the die are forced together so that the softened end of the tubular article is forced to move outwards until it abuts against a stop ring to form the flange. The residual shrinkage in the polymer material helps it to take up the precise contours of the die and to form a well-defined flange. The flanged end is then cooled, preferably to a temperature at least 20.degree. C. below the flanging temperature, before releasing the tubular body 10 from the die.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.