US3626137A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of electrical discharge machining
Assignee: Amsted Industries Inc
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Filing: 1970-03-25
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Granted: 1971-12-07
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Expires: 1990-03-25
Abstract
Abstract In electrical discharge machining, material is eroded away from a workpiece by electrical discharges occurring between an electrode and the workpiece. Coolant, that will change from a liquid to a gaseous state at a temperature and pressure below the temperature and pressure around the workpiece, is introduced in its liquid state into the gap between the electrode and the workpiece at the same time electrical discharges are passed across said gap. The liquid coolant experiences a temperature increase and a pressure decrease in the gap and flashes into its gaseous state thereby increasing in volume. Such volumetric increase results in a rapid gas flow away from the gap into the area around the workpiece that removes eroded particles. The change of state from a liquid to a gas is also accompanied by a decrease in temperature of the surrounding area including the electrode and the workpiece.
Inventors
- 👤 Robert Bernard Bertolasi
- 👤 Douglas Martin Hood
- 👤 Walter Avery Strange
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:38
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/08
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
101 words
A method of electrical discharge machining of an electrically conductive workpiece comprising the steps of locating an electrode adjacent said workpiece to form a gap between the electrode and the workpiece, and then passing a series of electrical discharges between said electrode and said workpiece across said gap while simultaneously changing a liquid dielectric coolant completely into a gas in the area of said electrical discharges and maintaining the pressure and temperature of the environment around the electrode and the workpiece at respective pounds per square inch and degrees Fahrenheit at which the dielectric can only exist in a gaseous state.
Claim 2
Independent Claim
101 words
A method of electrical discharge machining of an electrically conductive workpiece comprising the steps of locating an electrode adjacent said workpiece to form a gap between the electrode and the workpiece, and then passing a series of electrical discharges between said electrode and said workpiece across said gap while simultaneously changing a liquid dielectric coolant completely into a gas in the area of said electrical discharges and maintaining the pressure and temperature of the environment around the electrode and the workpiece at respective pounds per square inch and degrees Fahrenheit at which the dielectric can only exist in a gaseous state.
Claim 3
Dependent Claim
30 words
The method of claim 1 including the step of choosing a dielectric which is nonflammable and which volumetrically expands over one hundred times in changing from a liquid to gas.
Claim 4
Dependent Claim
23 words
The method of claim 1 including the step of choosing a dielectric which is a halogenated hydrocarbon containing one or more fluorine atoms.
Claim 5
Dependent Claim
29 words
The method of claim 3 wherein said liquid dielectric turns to a gas at a temperature below 0* Fahrenheit and a pressure below 15 pounds per square inch absolute.
Claim 6
Independent Claim
108 words
A method of electrical discharge machining comprising the steps of locating an electrode Having a passage therethrough adjacent a conductive workpiece to form a gap therebetween at the opening of said passage, and then passing a series of electrical discharges between said electrode and said conductive workpiece across said gap while simultaneously feeding a dielectric in its liquid state through said passage toward the area of the gap and maintaining the temperature and pressure of the environment in the area of the electrode and the workpiece at respective states of degrees Fahrenheit and pounds per square inch at which the dielectric can only exist in its gaseous state.
Claim 7
Independent Claim
108 words
A method of electrical discharge machining comprising the steps of locating an electrode Having a passage therethrough adjacent a conductive workpiece to form a gap therebetween at the opening of said passage, and then passing a series of electrical discharges between said electrode and said conductive workpiece across said gap while simultaneously feeding a dielectric in its liquid state through said passage toward the area of the gap and maintaining the temperature and pressure of the environment in the area of the electrode and the workpiece at respective states of degrees Fahrenheit and pounds per square inch at which the dielectric can only exist in its gaseous state.
Claim 8
Dependent Claim
39 words
The method of claim 5 including the step of choosing a dielectric which changes from its liquid state to its gaseous state at a pressure below 15 pounds per square inch absolute and at a temperature below 100* F.
Claim 9
Dependent Claim
32 words
The method of claim 6 wherein the density of said dielectric in its liquid state is at least one hundred times greater than the density of said dielectric in its gaseous state.
Claim 10
Dependent Claim
20 words
The method of claim 7 wherein said dielectric is completely changed to its gaseous state prior to leaving said gap.
Claim 11
Independent Claim
113 words
A method of electrical discharge machining comprising the steps of locating an electrode and an electrically conductive workpiece in space relationship to form a gap therebetween, then passing a series of electrical discharges across said gap between said electrode and said conductive workpiece to separate particles from said workpiece while simultaneously flowing a liquid dielectric fluid through and around said gap to remove said particles from said gap, and then stopping said flow of said liquid dielectric fluid to said gap and then expanding a liquid dielectric coolant to a gas in the area of said gap to remove said separated particles from said gap and cool said electrode and said conductive workpiece.
Claim 12
Independent Claim
113 words
A method of electrical discharge machining comprising the steps of locating an electrode and an electrically conductive workpiece in space relationship to form a gap therebetween, then passing a series of electrical discharges across said gap between said electrode and said conductive workpiece to separate particles from said workpiece while simultaneously flowing a liquid dielectric fluid through and around said gap to remove said particles from said gap, and then stopping said flow of said liquid dielectric fluid to said gap and then expanding a liquid dielectric coolant to a gas in the area of said gap to remove said separated particles from said gap and cool said electrode and said conductive workpiece.
Claim 13
Dependent Claim
64 words
The method of claim 9 wherein said dielectric coolant is fed in its liquid state through a passage in said electrode that opens into said gap, and said pressure of said dielectric coolant is rapidly reduced and said temperature of said dielectric coolant is rapidly increased in said passage proximate said gap to completely change said dielectric coolant from a liquid to a gas.
Claim 14
Dependent Claim
41 words
The method of claim 10 wherein the pressure and the temperature around said electrode and workpiece is at respective states of pounds per square inch and degrees Fahrenheit at which the dielectric coolant can only be maintained in a gaseous state.
References Cited (Backward Citations)
US3346713A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |