Wire electric discharge machine and method of controlling wire electric discharge machine

A wire electrical discharge machine configured to detect an end surface position of a placed object that is placed on a work table by applying a voltage between a wire electrode and the placed object, the wire electrical discharge machine comprising:

• a voltage detection unit configured to detect a voltage between the wire electrode and the placed object;
• a determination unit configured to determine, based on the detected voltage, whether or not the wire electrode has come into contact with the placed object;
• a relative movement control unit configured to cause an end surface detection operation to be performed a predetermined number of times, in which, from a state in which the wire electrode is separated away from the placed object, the wire electrode moves relatively in a manner so that the wire electrode comes into contact with the placed object, and when it is determined that the wire electrode has come into contact with the placed object, the wire electrode moves to a movement starting position, or alternatively, from a state in which the wire electrode is in contact with the placed object, the wire electrode moves relatively in a manner so that the wire electrode separates away from the placed object, and when it is determined that the wire electrode has separated away from the placed object, the wire electrode moves to a movement starting position;
• a storage control unit configured to, in each of the end surface detection operations, store in a storage unit a relative position of the wire electrode with respect to the work table at a time when it is determined that the wire electrode has come into contact with the placed object or at a time when it is determined that the wire electrode has separated away from the placed object;
• a data extraction unit configured to, in a case that a plurality of the relative positions are arranged in an ascending order, extract, as valid data, a plurality of relative positions that are positioned in a predetermined range that lies in a middle of the order;
• and
• an end surface position determination unit configured to determine the end surface position of the placed object based on the valid data.