Patent US3875374A successfully refreshed from Google Patents.
US3875374A
Expired / Lapsed
US
⏱️ 0.0 years remaining
EDM parameter control system
Assignee: Japan Kinoko Research Center Foundation
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Filing: 1973-03-07
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Granted: 1975-04-01
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Expires: 1993-03-07
Abstract
Abstract An EDM apparatus in which the control system is fully adaptive by having a reference counter which is stepped up or down depending upon the occurrence of undesirable discharge conditions. The control system thus includes a counter receiving signals representing a desirable gap condition over a relatively short time period and signals representing the non-development of the undesirable condition over a relatively long time period as established by appropriate timer means. A parameter of the gap is controlled in response to a comparison of the gap condition over a sequence of pulses with a desirable state as represented by the count registered in the counter.
Inventors
- 👤 Kiyoshi Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:52
CPC Classifications
B; B23; B23H; B23H7/00; B23H7/14; B23H7/16; B23H1/00; B23H1/02; B23H1/022; B23H7/18
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
278 words
A system for controlling the operation of an electrical discharge machining apparatus including power-supply means for passing a series of electrical discharges across a dielectricfilled machining gap between a tool electrode and a workpiece to remove material from the workpiece, servofeed means for relatively displacing said tool electrode and said workpiece as material removal therefrom proceeds so as to maintain a substantially constant working-gap spacing, and reciprocating means operable independently of said servofeed means for intermittently retracting said tool relative to said workpiece to clear machining product from said gap, said system comprising: monitoring circuit means electrically connected across said machining gap and responsive to the electrical characteristics of the machining gap for providing a first signal upon detection of the occurrence of an undesirable machining condition determined by electrical characteristics different from those prevalent upon material removal in the gap within a first time period, and providing a second signal upon nondEtection of said undesirable machining condition in the gap throughout a second time period, said monitoring circuit means including timing means for imparting to said second period a duration greater than that of said first period; control means electrically connected in circuit with the output of said monitoring circuit means and operatively connected with said reciprocating means for controlling the distance through which said tool electrode and said workpiece are relatively retracted and the intervening time interval between successive cycles of intermittent relative retraction of said tool electrode and said workpiece so as to increase said distance and simultaneously decrease said time interval in response to said first signal and to decrease said distance and simultaneously increase said time interval in response to said second signal.
Claim 2
Independent Claim
278 words
A system for controlling the operation of an electrical discharge machining apparatus including power-supply means for passing a series of electrical discharges across a dielectricfilled machining gap between a tool electrode and a workpiece to remove material from the workpiece, servofeed means for relatively displacing said tool electrode and said workpiece as material removal therefrom proceeds so as to maintain a substantially constant working-gap spacing, and reciprocating means operable independently of said servofeed means for intermittently retracting said tool relative to said workpiece to clear machining product from said gap, said system comprising: monitoring circuit means electrically connected across said machining gap and responsive to the electrical characteristics of the machining gap for providing a first signal upon detection of the occurrence of an undesirable machining condition determined by electrical characteristics different from those prevalent upon material removal in the gap within a first time period, and providing a second signal upon nondEtection of said undesirable machining condition in the gap throughout a second time period, said monitoring circuit means including timing means for imparting to said second period a duration greater than that of said first period; control means electrically connected in circuit with the output of said monitoring circuit means and operatively connected with said reciprocating means for controlling the distance through which said tool electrode and said workpiece are relatively retracted and the intervening time interval between successive cycles of intermittent relative retraction of said tool electrode and said workpiece so as to increase said distance and simultaneously decrease said time interval in response to said first signal and to decrease said distance and simultaneously increase said time interval in response to said second signal.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |