Wire electric discharge machining apparatus

A wire electric discharge machining apparatus that performs an electric discharge machining to a workpiece by applying a pulse voltage between a wire electrode and the workpiece, thereby generating a discharge pulse, in accordance with a first machining condition which is set, the wire electric discharge machining apparatus comprising:

• a machining speed detection unit configured to detect relative machining speed of the workpiece and the wire electrode;
• a machining energy calculation unit configured to calculate machining energy of the discharge pulse;
• a board thickness calculation unit configured to calculate a board thickness of the workpiece based on the machining speed detected by the machining speed detection unit and the machining energy calculated by the machining energy calculation unit;
• a stationary state determination unit configured to determine whether the machining is in a stationary state during the machining, after determining that the first machining condition is to be switched in accordance with the board thickness of the workpiece calculated by the board thickness calculation unit;
• and
• a machining condition switching unit configured to switch the first machining condition to a second machining condition corresponding to the board thickness calculated by the board thickness calculation unit based on the stationary state determination unit determining that the machining is in the stationary state and configured to not switch the first machining condition to the second machining condition corresponding to the calculated board thickness based on the stationary state determination unit determining that the machining is not in the stationary state.