US3588431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for electrical discharge machining using a substantially constant current density during a spark discharge
Assignee: Milacron Inc
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Filing: 1968-09-05
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Granted: 1971-06-28
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Expires: 1988-09-05
Abstract
Abstract A METHOD FOR MAINTAINING A SUBSTANTIALLY CONSTANT CURRENT DENSITY DURING A SPARK DISCHARGE IN ELECTRICAL DISCHARGE MACHINING WHEREBY THE WEAR OF THE TOOL ELECTRODE IS REDUCING SUBSTANTIALLY. ONE APPARATUS INCLUDES AN INDUCTANCE AND RESISTOR IN PARALLEL WHEREBY THE RESISTOR PRODUCES A PREDETERMINED MINIMUM CURRENT FLOW BETWEEN THE WORKPIECE AND THE TOOL DISCHARGE UPON START OF CURRENT FLOW THEREBETWEEN, AND THE INDUCTANCE REGULATES THE RATE OF INCREASE OF CURRENT FROM THE PREDETERMINED MINIMUM CURRENT TO MAINTAIN A SUBSTANTIALLY CONSTANT CURRENT DENSITY AS THE AREA OF THE DISCHARGE INCREASES.
Inventors
- 👤 Adrianus J Pekelharing
- 👤 Hendrik E De Bruyn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:14
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/02; B23H1/022
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-27 | 1974-12-27 | 1975-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-27 | 1978-12-27 | 1979-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-27 | 1982-12-27 | 1983-06-28 | $7700.00 | Window Closed / Lapsed |