摘要 |
In a machining device such as a wire cut electric discharge machine, an electrically conductive rubber member is attached to the machining solution jetting nozzle of its machining head in such a manner that, when the machining head abuts against the workpiece, the resistance of the rubber member is changed being compressed by the nozzle and the workpiece, and the change in resistance of the rubber member is detected to determine whether the change in resistance is normal or abnormal, thereby to detect the collision of the nozzle with the workpiece, whereby the machining head is protected from damage.
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