US3723690A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spark erosion of materials
Assignee: AT&T Inc
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Filing: 1971-08-09
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Granted: 1973-03-27
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Expires: 1991-08-09
Abstract
Abstract A method is described for the spark erosion of certain insulators and semiconductors such as Al2O3 and SiC involving forming a metal layer on the surface of the material to be eroded, positioning a movable electrode above the surface, initiating electrical sparking across the gap between the electrode and the metal layer, and then advancing the electrode toward the surface so as to maintain sparking, resulting in spark erosion of the surface. The method enables the implacement of holes of a variety of shapes and sizes at erosion rates of about 3 to 10 micrometers per second.
Inventors
- 👤 Y Nakada
- 👤 D Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:38
CPC Classifications
B; B23; B23H; B23H1/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
32 words
The method of claim 1 in which the erosion rate is at least 3 micrometers per second, the gap is at least 0.0015 millimeters, and the potential is at least 50 volts.
Claim 2
Dependent Claim
25 words
The method of claim 1 in which prior to spark erosion the surface of the body to be eroded is contacted by a dielectric liquid.
Claim 3
Dependent Claim
20 words
The method of claim 1 in which the metal layer is selected from the group consisting of copper and gold.
Claim 4
Dependent Claim
25 words
The method of claim 1 in which a plurality of electrically interconnected electrodes are provided to simultaneously erode the body at a plurality of locations.
Claim 5
Dependent Claim
11 words
A body of material eroded by the method of claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |