Mitsubishi Electric Corporation

Yasuo Onodera

Tatsushi Sato

Takashi Hashimoto

Hisashi Yamada

Yoshikazu Ukai

Koichiro Hattori

Hidetaka Katougi

Kazunari Morita

Hiroki Hikosaka

Takayuki Nakagawa

Tsutomu Yamamoto

Takashi Yuzawa

Takahiro Shiozawa

Masaya Kimura

Akihiko Iwata

Hidetaka Miyake

Seiji Satou

Atsushi Taneda

Hiroatsu Kobayashi

Yuhei Domori

Tamayo Ohata

Tatsushi Satou

Kozo Nomura

The roller-to-roller conveyance control apparatus includes an amplitude target setting unit that sets an amplitude target value of the tension deviation; an adjustment execution command generation unit that provides a command to adjust the control gain; an adjustment manipulated-variable output unit that outputs an adjustment manipulated variable; a manipulated-variable amplitude determination unit that increases the amplitude of the adjustment manipulated variable until the amplitude of the tension deviation becomes larger than the amplitude target value; and a control-gain calculation device that calculates the control gain from the amplitude and the vibration period of the tension deviation. A tension-shaft speed controller controls a tension-control-shaft motor on the basis of the line speed reference and the adjustment manipulated variable during the adjustment of the control gain.

Roller-to-roller conveyance control apparatus

A wire electrical discharge machining apparatus capable of improving the shape precision of a continuous corner part includes a corner speed coefficient calculation device calculating a machining speed ratio between a middle corner section and a straight part from a machining volume ratio between the straight part and the middle corner section in which machining volume becomes a constant value. A corner speed coefficient interpolation device interpolates a speed coefficient calculated by the corner speed coefficient calculation device in a pre-corner section and a post-corner section. A speed reference calculation device calculates a machining speed reference based on a representative speed and the corner speed coefficient, and a drive control device controls a drive device. A continuous corner detection device determines whether continuous corner sections overlap each other when the length of the straight part connecting two corner parts is shorter than the length of the pre-corner section.

Wire electrical discharge machining apparatus

An electric discharge machining system is provided which distinguishes an abnormal discharge caused by an immediate discharge and an abnormal discharge caused not by the immediate discharge to suitably control in each case. The electric discharge machining system according to the present invention that machines a workpiece by producing a discharge between an electrode and the workpiece, includes: a no-load-time detection means that detects no-load time of inter-electrode voltage between the electrode and the workpiece; an immediate-discharge determination means that compares the no-load time detected by the no-load-time detection means with predetermined time to determine whether or not the discharge is an immediate discharge; a voltage detection means that detects the inter-electrode voltage; an abnormal-discharge determination means that compares the voltage detected by the voltage detection means with a predetermined value to determine whether or not the discharge is a normal discharge; a discharge state assessment means that assesses a state of the discharge on the basis of the determination result of the immediate-discharge determination means and the determination result of the abnormal-discharge determination means; and a machining condition control means that controls a machining condition on the basis of the discharge state assessed by the discharge state assessment means.

Electric discharge machining system

In order to detect a wire breakage as soon as possible, the wire electrical discharge machining apparatus includes a speed fluctuation compensator that generates a speed fluctuation suppression command that is a speed compensation value that suppresses fluctuation of the rotational speed of the tension motor on the basis of the rotational speed of the tension motor and a breakage detecting device that detects a breakage of the wire electrode on the basis of a comparison of a preset breakage detection threshold and a speed fluctuation suppression command output from the speed fluctuation compensator.

An electric-discharge machining device including an electric-discharge-state determination unit that determines whether an electric discharging state between a machining electrode and a workpiece is either a state of normal electric discharge or of abnormal electric discharge, and a machining-condition switching unit that changes at least one machining condition, further includes a storage unit that stores therein an electric-discharge-state determination indicator, a standard-deviation calculation unit, and a boundary calculation unit that calculates a boundary to be applied to a determination in the electric-discharge-state determination unit based on the electric-discharge-state determination indicator, wherein the machining-condition switching unit changes the machining condition according to a comparison result between the standard deviation calculated by the standard-deviation calculation unit and a standard deviation reference set as a reference of the standard deviation.

Electric-discharge machining device

A numerical control device for a wire electric discharge machining apparatus generates a wire-breakage sign signal, outputs a machining-condition re-setting instruction and wire-breakage threshold re-setting instruction from the wire-breakage sign signal and wire-breakage threshold, sets the wire-breakage threshold according to the wire-breakage threshold re-setting instruction and a wire-breakage signal, calculates a machining energy from a discharge pulse count, measures a machining speed from position information, calculates a board thickness of the workpiece from the machining energy and machining speed, outputs, according to a predetermined algorithm, a machining-condition switching instruction from the board thickness, the machining-condition re-setting instruction, and the wire-breakage signal, sends an oscillation instruction to a oscillator and sends a shaft feed instruction to a servo amplifier so that the machining condition is set to one determined by the machining-condition switching instruction, and stores the machining condition and wire-breakage threshold that correspond to each board thickness.

Numerical control device, wire electric discharge machining apparatus using the same, and wire electric discharge machining method using the same

A wire electric discharge machining apparatus that performs an electric discharge machining by applying a pulse voltage between a wire electrode () and a workpiece (), the wire electric discharge machining apparatus including, a machining speed detection unit () that detects relative machining speed of the workpiece () and the wire electrode (); a machining energy calculation unit () that calculates machining energy of a discharge pulse; a board thickness calculation unit () that calculates a board thickness of the workpiece () based on the machining speed detected by the machining speed detection unit () and the machining energy calculated by the machining energy calculation unit (); a stationary state determination unit () that determines whether the machining is in a stationary state from a machining state during the machining, after the machining condition is switched in accordance with a board thickness of the workpiece () calculated by the board thickness calculation unit (); and a machining condition switching unit () that switches the machining condition to a machining condition corresponding to a board thickness calculated by the board thickness calculation unit () when the stationary state determination unit () determines that the machining is in the stationary state and does not switch the machining condition to the machining condition corresponding to a calculated board thickness when the stationary state determination unit determines that the machining is not in the stationary state.

Wire electric discharge machining apparatus

A wire electric discharge machining apparatus according to embodiments includes a wire electrode, a wire supplying unit that supplies the wire electrode, a collecting motor that collects the wire electrode at a predetermined speed, a tension motor that controls a tension of the wire electrode between the wire supplying unit and the collecting motor, a speed calculating unit that calculates a traveling speed of the wire electrode at a predetermined time interval, a speed storing unit that stores the traveling speed calculated by the speed calculating unit, a differential speed calculating unit that calculates a differential speed between a current traveling speed output from the speed calculating unit and a past traveling speed stored in the speed storing unit, and a breakage detecting unit that detects breakage of the wire electrode by comparing the differential speed with a predetermined threshold.

Based on a discharging gap value and machining allowance value stored in a corner-control-information storing means, a speed-ratio calculating meansbeing a machining-volume calculating means calculates machining volumes of a straight line portion and a corner portion to calculate a volume ratio therebetween. A corner-portion-speed calculating meanscalculates a machining feed speed at the corner portion based on a volume ratio calculated by the speed-ratio calculating means, and then outputs to a servo amplifieron the basis of the length of a pre-corner section outputted by a pre-corner-section calculating meansand the length of a post-corner section outputted by a post-corner-section calculating means, instructions about machining feed speeds from entering the pre-corner section till getting out of the post-corner section.

Wire electric discharge machine and wire electric discharge machining method

An object is to enable highly accurate machining by correcting machining conditions by referring to a programmed trajectory to obtain a desired machining shape. A wire electric discharge machining apparatus includes a machining-condition correcting unit that corrects machining conditions in each machining stage corresponding to a circular arc radius of a portion corresponding to a corner portion of a programmed trajectory, in the corner portion formed by changing a direction of relatively moving a wire electrode, when the wire electrode is moved on a wire center trajectory, which is offset from the programmed trajectory prestored in order to obtain a desired machining shape to perform finish machining in each machining stage with an offset amount being changed.

In a wire electrical discharge machining apparatus, an upper main-discharge power supply is connected between an upper conducting terminal and a workpiece using an upper main-feeder line capable of configuring outward and homeward paths, and a lower main-discharge power supply is connected between a lower conducting terminal and the workpiece using a lower main-feeder line capable of configuring outward and homeward paths. Moreover, a sub-discharge power supply is connected between the upper conducting terminal and the workpiece and between the lower conducting terminal and the workpiece using an upper and a lower sub-feeder lines that have higher impedances than the impedances of the upper and the lower main-feeder lines and can configure outward and homeward paths.

A controller of an electrical discharge machine comprises: a control unit that controls a machining condition set by the electrical discharge machine; an acquisition unit that acquires a parameter indicating an electrical discharge state between poles in a state where the machining condition is controlled by the control unit so that a normal electrical discharge occurs between the poles; an arithmetic unit that obtains a probability density distribution of the acquired parameter; a decision unit that decides a threshold that specifies a boundary between a normal electrical discharge and an abnormal electrical discharge between the poles based on the obtained probability density distribution; and a discrimination unit that discriminates whether the electrical discharge state between the poles is normal or abnormal by using the decided threshold, and wherein the control unit controls the machining condition based on a discrimination result of the discrimination unit.

Controller of electrical discharge machine

A wire electrical discharge machining apparatus includes a unit capable of separately opening and closing each of a high impedance path and a low impedance path, a unit that sets an open/close pattern in which a combination of closing one of the feeding paths and opening another one of the feeding paths is designated for switching power feeding between the high impedance path and the low impedance path, a unit that changes pulse energy per feeding pulse in a present feeding path to reduce a difference in discharge pulse energy applied to an inter-electrode gap from a machining power supply between at a time of high-impedance-path feeding and at a time of low-impedance-path feeding, and a unit that controls opening and closing of the path open/close unit in accordance with the changed open/close pattern.

A wire electric discharge machine includes a wire electrode; a machining power supply that supplies a machining current to between the wire electrode and a workpiece. The machine further includes a first power feed contact and a second power feed contact that respectively feed power to the wire electrode; a first machining-current loop in which a first machining current flows from the first power feed contact toward the workpiece; a second machining-current loop in which a second machining current flow from the second power feed contact toward the workpiece; an impedance switching circuit that is provided in at least any one of the first machining-current loop and the second machining-current loop; and a control unit that controls a flow ratio of the first machining current and the second machining current by changing an impedance of the impedance switching circuit.

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Chiyoda-ku, Japan

Yasuo Onodera