Manufacture of articles by drawing
US4372908A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 1980 |
| Grant date | Feb 8, 1983 |
| Priority date | — |
| Expiry date | May 30, 2000 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2031/716
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process for the manufacture of articles from a thermoplastic of polyester or polyamide type, preferably of polyethylene terephthalate, the articles being manufactured from elements which consist of an edge part which surrounds a body in an arrangement in which the latter is sunk relative to the edge part. The element is formed from a blank of mainly amorphous material or from a material having a crystallinity of less than 10%. The blank consists, for example, of a flat plate, a blank shell or the like. The body or parts thereof are shaped by stretching the blank until that material flows which is located within the material sections of the blank, which form the edge part in the element, the material stretched up to flowing in the body assuming a crystallinity of between 10 and 25%, while the crystallinity in the material in the edge part and in the unstretched parts retains its original value of less than 10%. The edge part is severed from the body which is elongated in the axial direction by a number of stretching steps, while the stretching at right angles to the direction of drawing is reduced at the same time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.