Electrical discharge machining apparatus including gap condition detection circuitry
US4634827A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 1985 |
| Grant date | Jan 6, 1987 |
| Priority date | — |
| Expiry date | Feb 15, 2005 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23H7/18
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Electrical discharge machining (EDM) apparatus includes an arc protection circuit which monitors the values of the ignition voltages applied across the gap between an electrode and a workpiece. A signal conditioning circuit includes a peak detector and averaging circuit conditions the voltage appearing across the gap and the arc protection circuit compares the value of the conditioned signal to the value of one of two reference voltage signals depending on whether the gap ignition voltages are increasing or decreasing. When the ignition voltages have decreased below the first reference level, the arc protection circuit provides a first control signal which causes a servo drive mechanism to increase the distance between the electrode and the workpiece. The first control signal also causes a pulse generator circuit to increase the off time between successive electrical discharges. When the ignition voltages have subsequently increased above a second, lower reference level the arc protector circuit provides a second control signal. The second control signal causes the servo drive mechanism to return to its programmed cutting position and the pulse generator circuit to return to its no…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.