| 摘要 |
With a simple structure, this device is capable of measuring the wire displacement accurately without any restrictions on the water injection and wire diameter during electrical discharge machining. Near the wire (10) are provided measuring electrodes (21) (+X) and (22) (-X) arranged in the axial direction X, and measuring electrodes (23) (+Y) and (24) (-Y) in the arranged axial direction Y. A discharge voltage is applied to the wire (10). The wire displacement is measured by the leak current from each of the electrodes. For example, in the axial direction X, the leak currents from the detection electrodes (21 and 22) are AC-coupled, and inputted into rectifying circuits (31 and 32). The rectified currents are made to pass through filters (41, 42), and the difference of the magnitude of the currents are calculated by a subtractor (51) and the sum of the currents are calculated by an adder (52). The sum is divided by the difference by a computing means (61), and the quotient is outputted as the displacement Xd in the X-direction. The wire displacement Yd in the Y-direction is similarly computed. |
