A multiwire electric discharge machine includes: a machining power source that applies a machining pulse voltage between a workpiece and a cutting wire section; and a wire breakage detection unit that detects breakage of a wire electrode. The wire breakage detection unit is electrically connected in parallel to a wire electrode portion stretched over a section from one location on the feeding side of the wire electrode to one location on the ejection side of the wire electrode, and the wire breakage detection unit includes: a wire breakage detection circuit in which a wire breakage detection power source constantly supplying direct current to the wire electrode portion at least while the workpiece is undergoing a cutting process and a current limiting resistor are connected in series; and a wire breakage determination unit that determines breakage of the wire electrode based on current flowing through the current limiting resistor.

Provided are an estimation method. and a control device for a wire electrical discharge machine, the method and device being for estimating the tension of a wire electrode on the basis of information obtained from a motor included in a feed mechanism of the wire electrode. A control device for a wire electrical discharge machine provided with a first motor and a second motor that induce rotation of a first roller and a second roller for feeding a wire electrode, the control device including: an acquisition unit that acquires a noise load and/or a torque command from one of the first motor and the second motor; a feed motor control unit that controls the first motor and the second motor so that the wire electrode is tensioned; and an estimation unit that estimates the tension on the basis of the noise load and/or the torque command for the time when the wire electrode is tensioned.

A follow-up swing head type large taper wire cutting device is disclosed. In the large taper wire cutting device, swing heads on upper and lower mechanical arms are adjusted in a follow-up way by swing head rotating mechanisms in coordination with a cutting taper, universal wire guide wheels are used to cooperate with the corresponding upper and lower swing heads, and tensioning mechanisms between the universal wire guide wheels and directional wire guide wheels are used for transition to ensure the smooth transition of an electrode wire, so that the electrode wire is effectively prevented from sliding off during large taper cutting, and the control of the follow-up deflection position of the electrode wire is also very accurate.

Provided is a wire electrical discharge machining device which has a tension controller for maintaining the tension of a traveling wire electrode at a tension. The tension controller includes: an allowed tension calculation module for determining an allowed tension that is less than a wire breaking tension at which the wire electrode breaks; and a set tension generation module for generating the set tension in accordance with the allowed tension. When the set tension is greater than the allowed tension, the set tension generation module reduces the set tension. When the set tension is less than the allowed tension, the set tension generation module increases the set tension in such a way that the set tension does not exceed the allowed tension.

An apparatus includes one wire electrode wound multiple times around a plurality of guide rollers to form a parallel wire part in which a plurality of wire cutting parts are arranged in parallel, a discharge waveform control device that controls an interpolar voltage waveform based on a discharge waveform command, and a wire running control device that controls running of the wire electrode based on a wire electrode running command. Further, there is a cutting stage drive device that controls a relative position between the parallel wire part and the workpiece based on a stage command, a machining state acquisition section that acquires a cutting part electrical characteristic or electrode state information as machining state information, and a machining control device that determines the wire electrode running command, the discharge waveform command, and the stage command based on the machining state information.

A high-speed reciprocating wire cutting process in which a wire electrode is transported and precisely guided across a machining area by means of a wire traveling circuit, whereas the cutting process is conducted by repeatedly: running the wire electrode in a first direction until a first reciprocation position, stopping and inverting the traveling direction of the wire electrode, running the wire electrode in a second direction until a second reciprocation position, stopping and inverting the traveling direction of the wire electrode.

A cutting process interruption sequence is carried out if a cutting process monitoring reveals that the cutting process must be interrupted, whereas the cutting process interruption sequence includes to continue the cutting process until the first or the second wire electrode reciprocation position, and to pause or to stop said cutting process at the wire reciprocation position.

A tension information acquisition device acquires tension of a wire electrode and is provided with: a back tension adjustment unit that makes the magnitude of back tension of the wire electrode zero; and an acquisition unit that acquires tension information indicating the tension on the basis of a disturbance estimate value or output torque of a feed motor when the magnitude of the back tension is zero.

The disclosure provides a wire electric discharge machine which has a simple configuration and can make a wire electrode fed to a machining position rotate around an axis. The wire electric discharge machine for machining a workpiece includes an upper wire guide and a lower wire guide, which stretch a wire electrode therebetween, and a rotator. A position of the rotator is changed, whereby the wire electrode is rotated around an axis.

A wire electrical discharge machine having an auto wire feeding function includes: guide parts arranged on a wire feed path along which the wire electrode is fed so as to guide the feeding of the wire electrode; fluid paths formed with the guide parts to supply a compressed fluid to the wire feed path; a compressed fluid supply device to supply the compressed fluid to the fluid paths; a tension detector to detect the tension of the wire electrode; and a control device that controls the compressed fluid supply device so as to supply the compressed fluid to the fluid paths, and based on the detection result from the tension detector, determines whether or not the wire electrode has reached a supply position of one of the fluid paths on the wire feed path to which the fluid has been supplied.

The wire electric discharge machining device includes a wire bobbin configured to wind and hold a wire electrode, a wire delivery roller configured to draw the wire electrode from the wire bobbin and deliver the wire electrode continuously toward a work-piece, a brake motor configured to apply a load to the wire bobbin in a direction against the drawing of the wire electrode, rotation speed detector configured to detect a rotation speed of the wire bobbin, an emptiness determination device configured to determine that the wire bobbin reaches an empty state based on a rapid change in the rotation speed of the wire bobbin detected by the rotation speed detector, and a drive control part configured to stop the drive of the wire delivery roller when the emptiness determination device determines that the wire bobbin reaches the empty state.