Electrical discharge machining device, electrical discharge machining method, and design method

An electrical discharge machining device comprising:

• a current supply circuit that supplies a current to a gap between an electrode and a machining target so as to provide electrical discharge machining, and
• a charge storage unit between the power supply unit and the coil unit,
• wherein the current supply circuit comprises
• a power supply unit,
• a coil unit between the power supply unit and the electrode, and
• a switching element that controls whether or not a voltage is applied to the gap between the electrode and the machining target,
• wherein a floating capacitance portion occurs in the gap between the electrode and the machining target,
• wherein, in the electrical discharge machining,
• after a charge stored in the floating capacitance portion is supplied to the gap, the power supply unit charges the floating capacitance portion, and
• a charge stored in the floating capacitance portion is discharged to the gap in a state in which the coil unit is delaying charge of the gap by the power supply unit,
• wherein the switching element continuously applies a voltage to the gap between the electrode and the machining target during a period in which the floating capacitance portion is discharged, the floating capacitance portion is charged, the voltage exceeds a discharge voltage and the floating capacitance portion is discharged again,
• wherein the charge storage unit stores a charge in the power supply unit before a discharge of the floating capacitance portion is completed,
• wherein the coil unit delays charge of the gap by the power supply unit and the charge storage unit while the charge stored in the floating capacitance portion is discharged to the gap,
• wherein the charge storage unit charges the floating capacitance portion using the charge thus stored after the floating capacitance portion is discharged, and
• wherein the coil unit and the charge storage unit provide a voltage waveform without overshoot and inhibit secondary discharge.