Apparatus for molding plastic
US4411609A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 1981 |
| Grant date | Oct 25, 1983 |
| Priority date | — |
| Expiry date | Apr 17, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C45/77
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method of and an apparatus for molding a plastic wherein the injection pressure (transfer pressure) is switched to a holding pressure when the internal pressure of the mold cavity sensed by a pressure sensor reaches a predetermined injection pressure (transfer pressure), to initiate holding of the pressure applied to the cavity. The holding pressure is removed when the internal pressure thereof becomes zero or in accordance with the detection of a predetermined inflection point in the internal pressure which is indicative of a gate sealing point in the mold cavity or is brought to a predetermined value close to zero. The molded articles are of high precision finishes, and conservation of energy and natural resources can be achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.