Molding arrangement to achieve short mold cycle time and method of molding
US5545366A · kind A · utility
Inventors
Key dates
| Filing date | Jun 10, 1994 |
| Grant date | Aug 13, 1996 |
| Priority date | — |
| Expiry date | Jun 10, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/812
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An arrangement for molding a front or back polystyrene mold half which is used, with a second complementary back or front mold half, for subsequent molding of a soft contact lens such as a hydrogel soft contact lens. Each mold half defines a convex curved surface and a concave curved surface spaced therefrom, with one of the surfaces defining an optical quality curved surface for the soft contact lens. A heated molding machine introduces molten polystyrene through a hot runner system to a plurality of mold cavities, each of which defines an optical quality curved surface and also a second noncritical surface. The optical quality surface of the mold cavity is positioned further away from the heated hot runner side of the mold than the second surface, which allows faster cooling of the optical quality surface of the mold cavity. Each mold cavity has a first insert on the optical quality side of the mold cavity and a second insert on the second side. Each of the first and second inserts has a circumferential cooling passageway defined therearound or in proximity for the first inserts, and also includes a bubbler positioned internally therein. Coolant is circulated in a turbulent mode …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.