JPS63105826A - Wire cut electric discharge machine - Google Patents

Abstract

PURPOSE:To sharply improve machining precision at a corner part, by providing a control means which predicts a change in a machining amount at a corner part and corrects a change in a gap between the sides of electrodes occasioned by a change in a machining amount. CONSTITUTION:In finish machining, a discriminator 12 outputs a signal by means of which a control device 14 is actuated when a present machining position is under circular movement of a corner part. The control device 14 selects a new interpole servo reference voltage for machining the preset corner part by means of signals from a discrimator 12 and a discriminator 13 for discriminating finish machining. The control device switches a reference voltage to the new reference voltage, and restores it to its original interpole servo reference voltage upon completion of machining of the corner. For. example, since, in the case of machining of an in-corner, with the increase in a machining amount, a gap between the sides of electrodes is increased to cause overcut, the control device 14 switches a reference voltage to an interpole servo reference voltage, in that the gap between the sides of electrodes is decreased, so that the overcut by a machining integration effect is corrected.

Description

[Detailed Description of the Invention] [Field of Application of M-Rakudo] The present invention relates to wire-cut electrical discharge machining, and particularly to improving its accuracy.

[Prior Art] FIG. 2 is a schematic diagram showing the configuration of a conventional wire-cut electrical discharge machine.

In Figure Cζ, (1) is a wire-shaped electric current i, <2) is the workpiece, (3) is the X slider that moves the workpiece (2) in the left and right direction in the figure, and (4) is the workpiece. The Y slider moves the workpiece (2) in the front and back direction in the figure, and the X slider (5)
3) is the servo motor that drives the servo motor, (6) is the Y slider (
(4) is a servo motor that drives the servo motor (5), (7) is a servo amplifier that supplies one current to the servo motor (5), (8) is a servo amplifier that supplies one current to the servo motor (6), (9)
is a machining solder source that supplies a bus-like t=X pressure between the wire-like poles (1) and the workpiece (2); The detector Ql) which detects the average machining voltage between 2) is a control device which controls the servo amplifiers (7) and (8) based on the signal of the detector αO and a predetermined machining program.

Next, the operation will be explained. The wire-shaped pole (1) runs at a predetermined speed 1, and a pulsed voltage is applied from the Ft source (9) to the wire-shaped electrode (1) and the workpiece (2) f7ftiζ
By applying a wire-like Z? Machining is performed by generating electrical discharge between (1) and the workpiece (2).

At that time, a movement command signal is sent to the servo amplifiers (7) and (8) based on the program locus that has been given to the control device @En in advance.The signal causes the servo motor (5X6) to move the X slider (3) and Y By driving the slider (4), processing into a desired shape is possible. Generally, the machining state changes from time to time, so the control device (6) uses the detector αO
The wire-like voltage 1 is determined by the average voltage between the poles detected by
@ X slider (3) and Y slider If at the optimal feed MH so that the machining gap between (1) and workpiece (2) is constant
f-(4). Normally, it is possible to obtain good shape accuracy and surface roughness by performing end face finishing several times after rough machining. Incidentally, shape refinement after finishing is determined by the electrode side gap, and in order to perform highly accurate shape processing, it is necessary to keep this electrode side distance 6j constant. Figure 8 is an enlarged view of the wire-shaped electrode (1) and workpiece (2) during finishing machining. The speed friction U decreases, and as a result, the machining integral effect increases in the wire side portion (portion A in the figure), and the one-plane gap Gs increases by tW.

That is, even if the machining electrical conditions and average servo voltage are the same, if the machining amount is changed, the electrode side gap will not be constant, and the shape accuracy after machining will deteriorate. FIG. 4 shows the values of IL and 'J1. when the machining electrical conditions and average servo voltage are the same. This figure shows the relationship between the i-side gap Gs, and the electrode-side 1-side gap G changes depending on the change in A-side iL.
It can be seen that s changes significantly. In actual shape machining, the change in machining capacity is greatest at a corner part, and Figure 5 is an enlarged view of the wire-shaped 'aL pole (1) and workpiece 12) during inside corner finishing machining. be. From the figure, it can be seen that the blow fi (L2-L4) at a part of the corner changes to a considerably large value compared to the blowing amount (Lo, L5) during straight line machining. Figure 6 is a diagram showing the change in takeoff flL at a part of the inner corner.
begins to increase and becomes a constant value, a certain distance before the end point of part of the corner! (H3 in the figure) The cutoff fL begins to decrease and becomes the change i in the straight line machining section again.

Therefore, as explained earlier, 1 pupil (m1 surface l!ll gap G
Since the expansion of s occurs, the shape after processing is significantly inferior. (FIG. 7) In addition, at the Awato corner, the side wall Gs of the road box decreases due to the decrease in convergence, so the shape after processing similarly deteriorates by -ζ.

[Problem that the invention seeks to solve]

Since the conventional wire-cut electrical discharge machine is configured as described above, the removal amount r, which occurs especially in some corners, etc.
With this change, the gap between the sides of the wire changes, resulting in problems such as a significant deterioration in the accuracy of the shape after processing.

This invention was made to solve the above-mentioned problems, and its object is to provide a wire-cut electric discharge machine that significantly improves the machining accuracy at a portion of a corner.

[Means for solving problems]

The wire-cut electric discharge machine according to the present invention is equipped with a control means that predicts in advance the change in removal amount at a part of the corner and corrects the change in the electrode side gap due to the change in the amount of cutting.

[Effect]

In this invention, the corner part cut fHF'(hi) prediction means corrects the change in the electrode side gap due to the breakage amount f(hi) from the information on the AH given in advance and the information indicating the current machining position and state. Operate the control device to improve machining accuracy at some corners.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained based on the drawings.

In FIG. 1, (1) is the wire K1. , (2) is the workpiece, (3) is the x7-'pider that moves the workpiece (2) in the horizontal direction in the figure, (4) is the workpiece < 2) yt
In the figure, the Y slider moves back and forth, (5) is the servo motor that fully drives the X slider (3), (6) is the servo motor that drives the Y slider (4), and (7) is the servo motor ( 5) a servo amplifier that supplies current to (8)
is a servo amplifier that supplies N current to the servo motor (6), (9) is a processing power supply that supplies a pulsed voltage between the wire-shaped electrode (1) and the workpiece (2), and αO is the wire-shaped electrode A detector that detects the average machining voltage between (1) and the workpiece (2), a control device that controls the servo amplifiers (7) and (8) based on the signal of the detector αO and a predetermined cutting edge; ■ is the first discriminator that determines whether the machining position is moving in a partial arc around a corner or not, 口 is the second discriminator that determines whether the machining is rough machining or end face finishing, α4 is the discriminator rt
This is a control device that switches the reference voltage of the gap servo using a2μs signal.

Next, the operation of the embodiment of this invention will be explained.

As in the conventional example, the wire-like KW (1) is run at a predetermined speed and processed '+t! (9) By applying a pulsed voltage between the wire-shaped electrode (1) and the workpiece (2), a discharge is generated between the wire-shaped electric FM (1) and the workpiece (2). The servo amplifier (7) (8) performs machining based on the program trajectory given to the control device in advance.
) A movement command signal is sent to the J motor (5) (6) according to that signal.7. M Ig-(3) Death! 1
．． HiY 7. '9. The desired shape is machined by driving the l'der (4). The control device Oυ controls the X slider ( 3) Shi and Y slider (4)
After rough machining, end face finishing is performed several times to obtain good shape accuracy and surface roughness. As mentioned earlier, the shape accuracy after finishing is determined by the electrode side gap, and in order to perform shape 9a machining with various precisions, it is important to keep this electrode side nS gap constant.

In finishing machining, the discriminator □□□ determines whether the machining position of the machine is moving in a partial arc around a corner or not, and sends a signal to operate the control device I when it is moving in a partial arc around a corner. do. Further, the discriminator side determines whether the current machining is rough machining or finishing machining based on the information from the control device α°C, and transmits a signal to operate the control device α4 only in the case of finishing machining. The control device α4 selects a new reference voltage for the gap servo for machining a part of the preset corner based on the discriminator (2) and the received signal from the house, and selects the reference voltage for the gap servo. When the corner W machining is completed, the voltage is returned to the original standard voltage of the servo between the poles.For example, in the case of inside corner machining, as the hammer capacity increases, the appeal of the electric shouting surface increases as the hammer capacity increases. Therefore, the control table a-!1 switches to the reference voltage of the Renmon servo, which reduces the electrode side gap, so that the overcapture due to the processing precision effect can be corrected.

These series of operations are automatically performed without the operator directly switching the reference voltage of the easy-to-read servo.

In addition, in the above embodiment, an example was shown in which the discriminator @ω and the control device a were provided independently, but if the same functions can be achieved, these should be performed by a single control device. It's okay. In addition, in the above embodiment, an example was given in which correction is performed only at a part of the inner corner, but from lζ, it is necessary to provide a fifth discriminator that discriminates whether the target corner is an inner corner or an out corner. It is possible to correct both.

〔Effect of the invention〕

As described above, according to the present invention, the change in removal amount at a part of a corner is predicted in advance, and the removal amount is determined in advance. Is there a gap between the side surfaces of the electrodes due to Ihi?
Since a control means for correcting the change in machining accuracy is provided, it is possible to prevent deterioration of machining accuracy due to changes in the electrode side gap due to changes in the removal amount that occur at some corners, etc. It has the effect of significantly improving change.

[Brief explanation of the drawing]

@ Figure 1 is a configuration diagram showing a wire-cut electric discharge machining machine according to an embodiment of the present invention, Figure 2 is a configuration diagram showing a conventional wire-cut electric discharge machine, and Figure 3 is a diagram showing a wire-shaped electrode and a workpiece during finishing machining. Figure 4 is an enlarged view of the workpiece. Figure 4 is a diagram showing the relationship between the cutting depth and the electrode side gap. Figure 5 is an enlarged view of the wire electrode and workpiece during inside corner finishing. Figure 6 is an enlarged view of the workpiece. FIG. 7 is a diagram illustrating overcapture in a part of the inner corner. (1) is a wire-shaped electrode, (2) is a workpiece, (3) is an XZ slider, (4) is a Y slider, (
5) (6) are servo motors, (7) and (8) are servo amplifiers, (9) is a processing power source, αO is a detector, 0°C is a control device, c12a3 is a discriminator, and α is a control device.

Claims (2)

[Claims] (1) In a wire-cut electrical discharge machine that generates an electrical discharge by applying a voltage between opposing wire-shaped electrodes and a workpiece, and performs machining by moving the wire-shaped electrode and the workpiece relative to each other, A first discriminator that discriminates whether the position is moving in a corner arc or not, a second discriminator that discriminates whether the machining is rough machining or end face finishing, and from the first and second discriminators. A wire-cut electrical discharge machine characterized by being provided with a control device that switches a reference voltage of a machining servo based on a signal. (2) It has a third discriminator that discriminates whether the target corner is an inside corner or an out corner, and the signals from the first and second discriminators described above and the third discriminator are used. The wire-cut electric discharge machine according to claim 1, further comprising a control device that switches the reference voltage of the gap servo based on a signal.