Patent ID: 7054712

Claim:
A wire contact/noncontact boundary position detecting apparatus for detecting a contact/noncontact boundary position of a wire electrode and a conductive object in a wire cut discharge machine, comprising: voltage application means for applying a detection voltage to between the wire electrode and the object; relative shift means for relatively shifting the wire electrode with respect to the object; control means for controlling a relatively approaching movement and a relatively separating movement of the wire electrode with respect to the object by the relative shift means; and contact judgment means for judging the state relating to the contact and noncontact of the wire electrode and the object based on the detection voltage, in the process of the relatively approaching movement and the relatively separating movement, wherein the control means controls the relative shift means such that the relatively separating movement is executed after the relatively approaching movement has been executed until the wire electrode and the object completely come in contact with each other, and the contact judgment means judges that, in the process of the relatively separating movement, the wire electrode has come out of the complete contact state with the object, according to a first standard relating to the transition of the detection voltage, and the relative position of the wire electrode, at a point in time when disengagement thereof from the complete contact state begins, is designated as a wire contact/noncontact boundary position.