US 6,208,150 B1Granted

Electrical discharge state detecting device for electrical discharge machining machine

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorKoji Akamatsu

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Abstract

An electrical discharge state detecting device for an electrical discharge machining machine which detects an electrical discharge state during an electrical discharge machining operation. The detecting device includes a high-pass filter for detecting a high-frequency component superimposed on an electrical discharge voltage or an electrical discharge current at a machining clearance between an electrode and a workpiece, a rectifying circuit for outputting a rectified component of the high-frequency component, a first integration circuit for integrating the rectified component, a reference voltage circuit, a second integrating circuit for integrating the reference voltage, a comparator for comparing the two integrated values, an electrical discharge generation detecting circuit for controlling starting and ending of the integrating circuits, a logic circuit, and a delay circuit and reset circuits.

Claims4

Dependent claims

An electrical discharge state detecting device for an electrical discharge machine, comprising:

high-frequency component detecting means for detecting a high-frequency component superimposed on one of an electrical discharge voltage and an electrical discharge current at a machining clearance between an electrode and a workpiece;
rectifying means for outputting a rectified component obtained by rectifying said high-frequency component detected by said high-frequency component detecting means;
first integrating means for integrating, over time, a magnitude of said rectified component outputted from said rectifying means;
reference voltage output means for outputting a reference voltage;
second integrating means for integrating, over time, a magnitude of said reference voltage outputted from said reference voltage output means;
integrating stopping means for stopping an integration in said first integrating means and said second integrating means only for a predetermined time on the basis of an operation of an internal switching element for use in current controlling of a machining power source;
control means for controlling starting and ending of integrations in said first integrating means and said second integrating means;
and
comparing means for comparing an integrated value obtained by said first integrating means with an integrated value obtained by said second integrating means.

6 more elements

An electrical discharge state detecting device for an electrical discharge machine operating on a workpiece, wherein said electrical discharge machine includes a power source under control of a switching element, said detecting device comprising:

an electrode disposed above the workpiece to detect an electrical discharge from the workpiece;
a high pass filter connected to said electrode to pass a high frequency component of the electrical discharge;
a rectifying circuit receiving the high frequency component and outputting a rectified signal;
a first integrator receiving the rectified signal as an input;
a reference voltage source supplying a reference voltage;
a second integrator receiving said reference voltage as an input;
a first mask limit circuit for detecting an on rise time of the power source in response to operation of the switching element;
a second mask limit circuit for detecting an off fall time of the power source in response to the switching element;
a logic circuit receiving outputs from said first and second mask limit circuits and outputting an integration control signal;
wherein said first integrator is connected and disconnected from the rectifying circuit in response to said integration control signal,
wherein said second integrator is connected and disconnected from the reference voltage source in response to said integration control signal;
and
a comparator receiving outputs from said first and second integrators to determine a state of the discharge.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/071,942Filed 5 May 1998 · division
Priority: JP 6-1873099 Aug 1994
Granted: 27 Mar 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

B23H 1/022
Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges: for shaping the…
B23H 1/024
Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges: detection of,…
B23H
Working of metal by the action of a high concentration of electric