Injection/compression molding method, a die for injection/compression molding and an injection/compression molding machine
US5340528A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1993 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Feb 16, 2013 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/575
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An injection molding die includes a fixed half die and a movable half die which has a core surface and which is provided with ejector pins. The ejector pins are held with their extremities retracted from the core surface to form recesses corresponding to compression allowances. The ejector pins are advanced toward the cavity to compress the compression allowances after a molten resin has been injected into the injection molding die in a manner which fills the cavity and the recesses. The compression with the ejector pins renders the pressure distribution int he cavity uniform, so that a molding can be formed with a high degree of accuracy and so that the injection molding cycle time can be reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.