JPS6144534A - Wire-cut electric discharge apparatus - Google Patents

Abstract

PURPOSE:To permit the stable work with high accuracy by installing a suspension controller for suspending the working feed at prescribed intervals onto a driving controller for providing the relative feed according to the working shape, in a wire-cut electric discharge apparatus. CONSTITUTION:In the electric discharge machining, motors 7 and 8 are driven by an NC controller 10, and the feed according to the worked shape is continuously performed. Since control is performed so that the working feed is suspended at prescribed intervals in this case, bending can be reduced. In other words, the fundamental clock pulses generated by an oscillator 12 are counted by a counter 13, and said counter 13 is a time apparatus which outputs a signal each time when the counted number reaches a preset value according to demand, and a control circuit 14 is operated by the time signals, and suspension control signals are applied into the apparatus 10, and applied into the motors 7 and 8 for a prescribed time, and the control signal is cut-off. Thus, stable work with high accuracy can be carried-out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a wire-cut electric discharge machining device that performs electric discharge machining using wires, tapes, etc. as electrodes.

[Prior art]

In wire cut electric discharge machining, as shown in Fig. 1, a wire electrode (or tape electrode) 1 is supplied from a reel 2, and a guide 3
The workpiece 4 is opposed to the wire electrode 1 between the guides with a predetermined tension and speed, and a machining power supply is connected between the electrode and the workpiece while supplying machining liquid from the nozzle 5. Machining is performed by applying pulse voltage and repeating electrical discharge.

During machining, the X-axis motor 1 and Y-axis motor 8 are driven and controlled by N CIII till according to the progress of machining, and the workpiece 4 is fed relative to the electrode in a machining shape. Cut into that feed shape.

According to this wire-cut electrical discharge machining, there is no need for shape electrodes for die-sinking machining, a new part of the TL pole is always supplied, there is no effect of electrode wear, and arbitrary shape machining can be easily performed with high precision. The wire electrode 1 has a wire diameter of 0.05 to 0.5
Since a fine wire of Cu or Bs with a diameter of 0.2 mm is used, it is not possible to apply a large tension to the wire, and the wire electrode is bent. This occurs because the electrical discharge pressure generated on the electrical discharge machining surface acts as a reaction force on the wire, and as shown in Fig. 2, the gap between the guide 3 and the workpiece 4 is curved. Processing debris is difficult to escape, arcing and short circuits are more likely to occur, and the trajectory in particular is 1.
b, and since it is cut along this path, the workpiece 4 has the disadvantage that the shape accuracy of the corners deteriorates.

[Technical problem solving means]

The present invention eliminates such drawbacks and enables stable, high-precision machining. Therefore, the present invention includes a stop control device that stops machining feed at predetermined intervals in a drive control till device that provides relative feed of the machining shape. It is characterized by having a set number.

〔Example〕 The present invention will be explained below with reference to an embodiment of the drawings.

In FIG. 1, reference numeral 10 indicates N which controls each motor 7.8 by generating an X-axis drive signal and a Y-axis drive signal while reading machining shape data and feed speed data from a command tape 11.
C control device, which is operated by the basic pulse signal of the pulse oscillator 12. 13 is a preset counter that counts basic pulses; 14 is a control circuit that operates when the counter 13 outputs a preset signal and temporarily interrupts the output signal of the NC control device 10; In addition, motor 7.8 is a pulse motor,
Any DC motor can be used, but pulse motors can be used with NC.
A pulse signal is applied from the control device 10, and when a DC motor is used, a DC voltage signal is applied from the NC control device, and the feed price is fed back and controlled by a position detector such as an encoder (not shown).

In the above, machining liquid (water) is supplied from the nozzle 5 to the opposing gap between the wire electrode 1 and the workpiece 4, a pulse voltage is applied thereto from the machining power source 6, and machining is performed by pulse discharge. . The pulse for processing is a rectangular wave pulse obtained by switching a DC voltage on and off using a switch such as a transistor, or a discharge of a capacitor whose charging is controlled by a switching output. During this electrical discharge machining, the motor 7.8 is driven by the NC control device 10 to continuously feed the machined shape, and the liquid is added:
[The body 4 is fed relative to the wire electrode-1 and cut according to the feeding shape.

The wire electrode 1 is supplied from a reel 2 and moved between guides 3 with a predetermined tension and speed by a brake and a capstan (not shown), and the pulse discharge by the power source 6 and the machining feed by the NC control device 10 are continuously performed. It is done. The discharge state of the machining gap is constantly detected by the detection device 9, which controls the reduction of the pulse that supplies the signal and stops it, decelerates and stops the machining feed when it is too fast, and controls the retraction and retraction when there is a short circuit. Control is performed so that stable machining can continue while this process is being carried out.

As a result, discharge pressure acts on the wire electrode 1 running between the guides with a predetermined tension, thereby
As explained in the figure, it is unavoidable that an arcuate deflection delay occurs on the opposite side to the direction in which processing progresses.

However, in the present invention, the processing feed is controlled to be stopped at predetermined intervals, so that the deflection can be reduced. That is, the counter 13 counts the basic clock pulses generated by the oscillator 12;
3 is a time device that outputs a signal every time a desired preset count value is reached; the control circuit 14 is actuated by this time signal, and an interrupt control signal is applied to the NC control device 10 to drive the drive motor 7 for a predetermined period of time. .Interrupt the control signal applied to 8.

Therefore, during this time, the motors 7 and 8 stop, and the feeding of the workpiece 4 stops, but the electric discharge from the power source 6 continues.
As a result, the deflection delay of the wire electrode 1 gradually decreases. After straightening the wire electrode 1 in this way, NC is performed again.
Processing is performed while outputting a feed signal from the control device 10 and giving a processing feed, and when the counter 13 reaches a predetermined count, that is, a predetermined time has elapsed, the NC-controlled processing feed is stopped again and the wire electrode 1 is processed. The bending is controlled and this process is repeated while processing the desired shape. That is, processing is performed while correcting the delay in deflection of the wire electrode at predetermined time intervals.

With this control, the wire electrode 1 is on average connected to the upper and lower guides 3.
The wire is guided almost linearly between the wires, which improves the flow of machining liquid to the machining gap, improves the removal of machining debris, improves machining speed, and allows stable wire cutting without wire breakage. , the machining accuracy of corners etc. will be improved.

For example, using a brass wire with a wire diameter of 0.2 mmφ and a thickness of 50 m.
When cutting the wire of S K D -11 material of m,
The tension of the wire electrode is 900'), and the traveling speed is 4.
m/min, and the machining fluid has a specific resistance of 1.2X 104ΩC.
Using 11 water, machining was carried out at an average machining current of 10△, and under the machining conditions that the machining speed was approximately 2 mm/min, the machining feed was stopped once every 15 seconds, and the When the interruption time width was controlled to 1.5 seconds to 0.75 seconds, the processing speed was approximately 3 mm/min to 2.7 mm/min.

That is, the processing speed was improved to about 1.4 to 1.5 times. Also, the width of the sag at the corner where the machining direction is changed to a right angle is approximately 0.09 m if the feed is not controlled to stop.
m, but due to the above-mentioned feed stop control, it was reduced to about 0.0
It decreased to 4mm.

It should be noted that the time interval of the control and the time width of stopping the feed will differ depending on conditions such as the diameter of the wire electrode, the material, the applied tension, the thickness of the workpiece, and the processing speed, so they must be set each time. No.

The above explanation has been about time control, but as mentioned above, in wire cut electric discharge machining, the discharge state of the gap is constantly detected by the detection circuit 9, and the number of repetitions of discharge pulses by the machining power source 6 is thereby controlled. , also, the NC control device 10
Since the machining feed speed is controlled by , it is possible to count the number of pulses of the feed signal of this NC control device and control to stop the feed every time a predetermined length of machining feed is given. Further, the machining feed distance can be detected and measured by a position detector such as an encoder or resolver engaged with the drive shaft of each motor 7.8, and machining feed is performed by a predetermined distance by detecting the machining feed distance. NC every time
The sending signal of the control device can be interrupted and controlled.

〔effect〕

As described above, according to the present invention, the machining feed is controlled to stop at predetermined machining distance intervals or predetermined machining time intervals, so that the inevitable bending delay of the wire electrode can be avoided during the feed stop control. Therefore, electrical discharge machining can now be performed with a wire electrode that does not bend on average, which increases the effect of removing machining debris and gas, and improves the flow of machining fluid into the gap. The machining speed can be increased by stable electric discharge machining, and since the wire electrode is cold and machining is performed while straightening the bending, corner edges can be machined with high precision.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of one embodiment of the device of the present invention, Figures 2 and 3 are
The figure is an explanatory diagram of the processing state of the wire electrode. 1...Wire electrode 2...Reel 3...Guide 4...Workpiece 5... ...... Machining fluid nozzle 6... Machining power supply 1.8... Motor 10... NC control device 12 ......Pulse oscillator 13...Counter 14...Control circuit patent applicant

Claims (3)

[Claims] (1) A wire electrode supplied from a reel is moved between the guides with the required tension and speed, and a pulse discharge is performed while supplying machining fluid to the gap between the guides, where the wire electrode and the workpiece face each other. In a wire-cut electric discharge machining device that repeatedly performs machining while giving a relative feed of the machining shape between the guide of the wire electrode and the workpiece, the machining feed of the drive control device that gives the relative feed of the machining shape. A wire-cut electrical discharge machining device characterized by being provided with a stop control device for controlling the stop at a predetermined gap. (2) The wire-cut electrical discharge machining apparatus according to claim 1, further comprising a stop control device that controls stopping of machining feed at predetermined machining distance intervals. (3) The wire-cut electric discharge machining apparatus according to claim 1, further comprising a stop control device that controls stopping of machining feed at predetermined machining time intervals.