| 摘要 |
<p>An apparatus (1) for electrochemically machining of a workpiece (2) by means of an electrode (30) has an actuator (8) for setting a gap (4) between the electrode (3) and the workpiece (2). The apparatus further has a channel (11) for flushing the gap (4) with an electrolyte (5) and a container (10) for containing the electrolyte (5). Power cords (12 and 13) are provided for feeding an electric current (I) supplied by a power supply (40) through the electrolyte in the gap (4). Near the gap (4) an antenna (21) is provided to pick up electromagnetic waves radiated from the gap (4). The antenna (21) is connected to a band-pass filter (22) which passes signals in a frequency band of 40 to 100 MHz to a level detector (23). The level detector (23) compares the amplitude of the filtered signal (Ua) with a threshold value and supplies a stop signal (Us) to the control unit (30) when the amplitude exceeds the threshold value. The control unit (30) is programmed to open a switch (43) in the power supply (40) in response to the stop signal (Us). The antenna (21), the band-pass filter (22), the level detector (23) and the control unit (30) together form a damage prevention system which can be used in an existing ECM set-up to prevent spark discharges.</p> |
