Process for producing a plastic foil of thermoplastic material
US5178806A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 4, 1991 |
| Grant date | Jan 12, 1993 |
| Priority date | — |
| Expiry date | Sep 4, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2948/92933
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process for the production of a plastic foil of thermoplastic material as well as for winding this plastic foil into a coil. The produced plastic foil has systematic thickness errors with plus thickness errors and minus thickness errors. The coil is practically free of thickness errors summed during winding. In order to achieve this, the thickness-error profile of the produced plastic foil with its systematic plus thickness errors and/or minus thickness errors is measured prior to the winding of the coil. A number n of layers of the plastic foil produced with the systematic plus thickness errors and/or minus thickness errors is wound up to a coil. After that, approximately a number n of layers of the plastic foil with the inverse thickness-error profile is wound on the coil. This is periodically repeated, n layers of plastic foil with the thickness-error profile alternating with approximately n layers with inverse thickness-error profile, until in the end the adequately cylindrical coil is produced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.