Method for controlling injection volume of material into mold
US5500166A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1994 |
| Grant date | Mar 19, 1996 |
| Priority date | — |
| Expiry date | Sep 15, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/562
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In an injection and compression molding process wherein molten material is fed by a screw, incorporating a counterflow preventing valve (CPV), through a flow control valve (FCV) into a mold cavity, the injection volume is controlled by: with the FCV closed, feeding a predetermined quantity of material through the CPV into a chamber between the CPV and the FCV, then advancing the screw with the FCV maintained closed to cause the CPV to close, thereby raising the pressure of the material in the chamber, determining when the pressure of the material in the chamber reaches a predetermined pressure, determining whether the movable die is at a predetermined distance from the stationary die, opening the FCV after the pressure of the material in the chamber has reached said predetermined pressure and the movable die is at the predetermined distance from the stationary die, setting as an original point of a determination of the injection volume either (a) a position of the screw at the opening of the FCV or (b) a time at the opening of the FCV, injecting the material into the mold cavity while the mold cavity is open to atmospheric pressure, closing the FCV either (a) when the screw has rea…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.