US Patent No. 9,126,277

POWER SUPPLY DEVICE FOR WIRE ELECTRIC DISCHARGE MACHINE CAPABLE OF SUPPRESSING WIRE ELECTRODE CONSUMPTION


Patent No. 9,126,277
Issue Date September 08, 2015
Title Power Supply Device For Wire Electric Discharge Machine Capable Of Suppressing Wire Electrode Consumption
Inventorship Tomoaki Matsunaga, Yamanashi (JP)
Akiyoshi Kawahara, Yamanashi (JP)
Assignee FANUC CORPORATION, Yamanashi (JP)

Claim of US Patent No. 9,126,277

8. A power supply device for a wire electric discharge machine, the power supply device comprising:
a main DC power source;
an auxiliary DC power source with variable voltage;
a first circuit configured to output a first pulse, stop the output of the first pulse, and then output a second pulse;
a second circuit configured to apply a first voltage from the main DC power source to a machining gap between a wire electrode
and a workpiece while the first pulse is being output from the first circuit, the second circuit comprising an inductance;

a third circuit configured to, while the second pulse is being output,
pass a current, which is generated by inductive energy stored by the inductance in the second circuit, between the wire electrode
and the workpiece, and

cause the auxiliary DC power source to apply a second voltage to the machining gap,
wherein
a period of application of the first voltage from the main DC power source and a corresponding period of application of the
second voltage from the auxiliary DC power source are pre-stored in a data table,

the period of application of the second voltage corresponds to a peak current value provided by the main DC power source at
the end of the first pulse,

in response to the peak current value being a first current value, the period of application of the second voltage has a first
duration during which the current is maintained at the first current value, and

in response to the peak current value being a second current value, the period of application of the second voltage has a
second duration during which the current is maintained at the second current value, the second current value is greater than
the first current value, and the second duration is shorter than the first duration; and

a fourth circuit configured to return the current generated by the inductive energy stored by the inductance in the second
circuit to the main DC power source when the output of the second pulse is stopped.