摘要 |
An electric discharge machine performs a hole machining on a workpiece by applying a voltage between an electrode and the workpiece to generate an electric discharge therebetween and moving the electrode to a position of a command depth. The electric discharge machine comprises: a storage unit; a current-coordinate detection unit; an electric-discharge-voltage detection unit a penetration detection unit; and a calculation unit. The storage unit stores therein a penetration determination voltage, a penetration determining duration, and a first projecting amount. The current-coordinate detection unit detects a current position of the electrode. The electric-discharge-voltage detection unit detects a minimum voltage of the electric discharge for each predetermined period. The penetration detection unit determines the electrode has penetrated through the workpiece. The calculation unit calculates, a position obtained by adding the first projecting amount to the current position of the electrode detected by the current-coordinate detection unit and updates the command depth.
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