Method of controlling vacuum in vacuum die-casting and vacuum control system for carrying out the same
US5782287A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1996 |
| Grant date | Jul 21, 1998 |
| Priority date | — |
| Expiry date | Jun 7, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB22D17/32
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of controlling vacuum in vacuum die-casting and a vacuum control system for performing the same adjusts the time to open a vacuum valve to start degassing in connection with the position of an injection plunger to control vacuum in a cavity so that gases may not be involved in a molten metal injected into the cavity. The method comprises opening the vacuum valve to start degassing the cavity upon the advancement of the injection plunger to a first position. The vacuum in a vacuum system is measured upon the arrival of the injection plunger at a second position immediately before a final position where the injection plunger completes the injection of the molten metal. A measured vacuum is compared with a predetermined reference vacuum. The first position is shifted by a predetermined distance toward the die when the measured vacuum is higher than the reference vacuum or by a predetermined distance away from the die when the measured vacuum is lower than the reference vacuum to set a corrected first position. The vacuum valve is opened when the injection plunger arrives at the corrected first position in the next injection cycle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.