JPS6362618A - Wire cut electric spark machine - Google Patents

Abstract

PURPOSE:To enable electric spark machining at a high speed and with high efficiency while stably maintaining contact electrification state of a wire electrode with electrifying elements by controlling a machine in such a way that the contact electrification state is turned into an optimum level on the basis of the signal detected by a contact detector. CONSTITUTION:Electrifying elements 2, 3 which are pressurized and slided with a wire electrode 1 deform due to their wear with the continuation of machining. A magnet attracts a lever 5 with a fixed exciting current to exert pressure, decreasing contact pressure for lowering the level of the detection signal of a piezoelectric element 11, thereby increasing the output signal compared with the reference value of a comparison circuit 13, for making control so as to excite an excitation coil strongly through the control of a control power source 15. The increase of pressurizing force of electrification element 3 make the detection signal of an element 11 increase to increase the level of the signal applied from a detection circuit 12 to the circuit 13, thereby lowering the comparison output of circuit 13, and controlling the excitation so as to maintain it as it is. Therefore, even if the electrification elements are worn, the contact pressure with the electrodes can be maintained constantly and the electrification state is made constant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a wire-cut electrical discharge machining apparatus that performs electrical discharge using a thin wire electrode.

[Prior art and problems]

Conventionally, wire cut discharge application I l! i PI ('J
It is known that the machining current is applied to the wire electrode by providing a conductor in contact with the wire electrode. If the pressure is applied to the cellar 1 using a spring or the like, it will not change during the process. In this case, both the plunger and the roller are worn out and the contact state changes with continuous use. Normally, contact pressure decreases due to wear of the conductor, and current conduction resistance increases. If electrical discharge machining is continued under such situational changes, the machining current will gradually decrease and the machining efficiency will decrease, heat will be generated due to the contact resistance between the current conductor and the wire conductor 1, and sparks will be generated between the two. This has the disadvantage of causing wire breakage. In particular, in recent years, high-speed machining technology that uses large currents has been developed, causing the problem of faster wear of the current-carrying bottle.

[Means for solving problems]

In order to eliminate the conventional drawbacks, the present invention includes a pressurizing device that can control the pressure applied to the conductor and a contact detection device that detects the contact state between the wire electrode and the conductor. A special embodiment characterized in that a control circuit is provided to control the pressurizing device so as to optimize the contact energization state between the wire electrode and the energizing element based on the detection signal of . The invention will be explained by examples.

1 is a thin wire soy A with a wire diameter of 0.03-o and a smmφ culm.
It has 7 electrodes and is usually supplied from a winding reel, and is moved with a predetermined tension and speed by the action of a pulling device and a brake (see 4). For discharging, the workpiece is placed opposite the moving wire electrode 1. 2 is a stator for passing machining current to the solenoid electrode 1, and 3 is a stator from the opposite side. 4 is an insulator pressure guide;
5 applies pressure to the guide 4 via a ball 6. 7 is an electric current 1a T, + iron core (゛,) By excitation of the iron core 8, the magnetic attraction force is applied to the 5 supports of the - grass) to perform pressurization control. 9 springs (with springs that repel magnetic attraction force,
Apply electromagnetic force to this spring with resistance 1), lever 5, guide 4,
Pressure is applied to the conductor 3. Fixed side power supply 2 is connected to fixed wall surface 1
0, with the piezo element 11 sandwiched between them to detect the pressure car electric signal. 12 is a signal detection circuit from the piezo element 11, 13 is a signal comparison circuit, and the comparison reference value is appropriately set by setting KIF/+4. The standard value is Soi A
The optimum value can be set depending on the quality, wire diameter, machining pulse conditions, etc. of 7D4411, or it can be set by manual or NC program control. Reference numeral 15 denotes an excitation control power supply for supplying an excitation current to the coil 8, which performs excitation control based on the output signal of the comparator circuit 13. 16 is a lead wire that connects and covers the processing power source 2.

In step 2, insert the wire electrode 1 between the conductors 2 and 3,
The initial setting of the pressurizing force is to apply magnetic attraction by excitation of the magnet coil 8 and pressurize the lever 5, and to apply electricity to the lever 5 from the pressurizing guide 4.
Pressure is applied to maintain the contact energization state with the wire electrode 1 at an optimum value. The detection signal of the piezo element 11 in this state is within the appropriate pressure range, and the signal of the detection circuit 12 that detects this is added to the comparison circuit 13 for comparison 4, and the control is controlled by the comparison output. The power supply 15 maintains its initial state.

However, as the machining continues, the sliding conductors 2 and 3 will wear out and become deformed due to the moving wire electrode 1. When the conductors 2 and 3 wear out, the pressure contact force decreases and the detection signal of the vinyl element 11 decreases.This causes the comparison circuit to The output signal compared with the base lil value of lil 13 increases, and the control power supply 15 controls the excitation=1 lil 8 to be strongly excited.

As a result, if the pressurizing force of the conductor 3 increases, the detection signal of the piezo element 11 increases, and the signals applied to the detection circuit 12hl and the comparison circuit 13 increase, so the comparison output of the Ik comparison circuit 13 decreases and the control The power supply 15 is controlled so as to maintain the excitation of the coil 8, and thereby the current supply 2 is
．． Even if the pressure contact force of the wire electrode II 1 is maintained constant due to wear of the wire electrodes 3 and 3), the contact energization state of both wires is always controlled to be constant. For this reason, it is possible to avoid lowering the current and reduce efficiency as in the past, and to completely prevent wire electrode disconnection accidents due to heat generation and sparks due to poor contact.
1? It is possible to perform stable and highly efficient wire-cut discharge.

In addition, the comparison with the M standard value of the detection signal can be carried out by 1) 11g t [Not limited to comparison, digital f discrimination can be #j/,'l, and the reference tv-value can be set in several stages. Outputs the judgment and controls.
5-. The power supply 15 can be digitally controlled in stages 1). In addition, the contact state between the conductor and the wire electrode may be detected by detecting changes in the conduction resistance or current between the two, and various types of corresponding detection devices may be used. Further, as the pressurizing device for pressurizing and controlling the conduction of electrons, thermal expansion, magnetostrictive, electrostrictive, other electrical, mechanical actuators, liquid, and gas actuators can be arbitrarily used.

In addition, in the embodiment, two energizers were provided facing each other with the wire electrode 1 in between, but one of the energizers could also be energized by a pressure pad.
However, even in that case, stable energization can be achieved by detecting the contact state and controlling the pressurization to maintain a constant energization state. 1-1- to energized r:)
The same is true when using .

〔Effect of the invention〕

As described above, the present invention detects the contact state between a wire electrode and a current-carrying element using a pressurizing device that can control a pressure horn on a current-carrying current.
a contact detection device, and further controls the pressurizing device based on the detection signal of the contact detection device (to optimize the contact state between the 11 electrodes and the current-carrying wire). A control circuit is installed (Since it is a J-type, even if the conductor is worn out, it can be used to control the pressurizing device. 1) Optimally control the contact pressure with the twist electrode I throat 8M! Stable conduction state Keep the current flowing to a low level/'C<always on' - Control the pulse peak value, pulse width, and waveform to a constant value without changing them.
) (Stable 1.: Fast hemp, high efficiency discharge pressurization (・Saru 1, again?, Y, Bad contact between the rice wire electrode and the current conductor iJ: J: Resulting heat generation, spark It is possible to completely prevent the electrode disconnection accident that occurred in the previous process, and to perform stable electrical application.In addition, it is possible to perform the electrical application manually in one program during the NC installation. By optimally controlling the contact pressure, which is strong during rough machining and weak during rough machining based on the
(+1 becomes lil flli.

[Brief explanation of the drawing]

The drawing is a configuration diagram of an embodiment of the present invention. 1...Wire electrode 2.3...Electrification 4...Pressure guide 5...Pressure Pressure lever 6... Pressure ball 7... Magnetic core 8... Excitation] Ill 9... Spring 11...Piezo cable 12...Signal IJ detection circuit 13...
... Comparison circuit patent applicant Kiyoshi Inoue, Representative of Tsuki-1 Nijavax Institute, Inc.

Claims (1)

[Claims] In an apparatus for machining by supplying machining liquid to a gap facing a workpiece while moving a wire electrode between guides with a predetermined tension and speed, and repeating pulse discharge by applying electricity, the moving wire is A wire-cut electrical discharge machining apparatus characterized in that a current-carrying current is provided in contact with an electrode, and a pressure device is provided on the current-current current that can control the pressing force.