JPS63105828A - Wire cut electric dicharge machine - Google Patents

Abstract

PURPOSE:To 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 gas between the sides of electrodes occasioned by a change in a machining amount. CONSTITUTION:In finish machining, a discriminator 12 discriminates whether a present machining position is under circular movement of a corner part, and outputs a signal, by means of which a control device 13 is actuated, when under circular movement of the corner part. The control device 13 switches the gain of a new interpole servo for machining a preset corner part by means of a signal from the discriminator 12, and restores the gain to its original upon completion of machining of a corner. Since, for example, 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 13 switches the gain of an interpole servo to a low value to prevent the occurrence of phenomenon, in that a machining speed is excessively decreased at the in- corner part, and as a result, overcut is corrected by a machining integration effect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a wire-cut electric discharge machine, and particularly to its high precision.

[Conventional technology]

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

In the figure, (1) is a wire-shaped electrode, (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 (2). The Y slider (5) moves the body back and forth in the mouth, and the X slider (3)
) fully driven servo motor, (6) is the Y slider (4
) is the servo motor that drives the servo motor (7).
), (8) is a servo amplifier that supplies current to the servo motor (6), and (9) is a servo amplifier that supplies a current to the servo motor (6). Based on the supplied machining power supply, (1G is a detector that detects the average machining voltage between the wire-shaped electrode (1) and the workpiece (2), and ■ is the signal from the detector QG) and a predetermined machining program.
This is a control device that controls the servo amplifiers (7) and (8).

Next, the operation will be explained. The wire-shaped electrode (1) runs at a predetermined speed, and a pulsed voltage is applied between the wire-shaped electrode (1) and the workpiece (2) from the processing power source (9), so that the wire-shaped electrode ( 1) Machining is performed by generating an electric discharge between the upper workpiece (2). At this time, the servo amplifiers (7) (8) A movement command signal is sent to 1,
A servo motor (5×8) drives the X slider (3) and Y slider (4) based on the signal, thereby making it possible to process the desired shape. Generally, the machining condition changes from time to time, so the control device αD is optimized so that the distance between the wire-shaped electrode (1) and the workpiece (2) remains constant based on the average voltage between the electrodes detected by the detector αq. The X slider (3) and the τ slider (4) are driven at a feed rate of Normally, it is possible to obtain good shape accuracy and surface roughness by performing end face finishing several times after rough machining. By the way, the shape accuracy after finishing processing is determined by the electrode side gap, and in order to perform highly accurate shape processing, it is necessary to keep this electrode side gap constant. FIG. 8 is an enlarged view of the wire-shaped electrode (1) and workpiece (2) during finishing processing.
In conventional general average voltage constant control, the
When L increases, the machining speed U decreases, and as a result, the machining precision effect applied to the wire side portion (portion A in the figure) increases, and the electrode side gap GS increases. That is, even if the machining electrical conditions and the average servo voltage are the same, if the loss amount changes, the electrode side gap will not be constant, and the shape after machining will deteriorate. Figure 4 shows the relationship between the machining capacity and the electrode side gap 0 days when the machining electrical conditions and the average servo voltage are the same. I know that it will change and become b. In actual shape machining, the maximum change in machining weight occurs at a corner part, and Figure 5 shows the wire-like electric wire (1) and the workpiece (2) during in-corner finishing machining.
) is an enlarged diagram. From the figure, the removal amount during straight line machining (L
O, L6), the removal amount at a part of the corner (L2-I,
It can be seen that 4) changes to a considerably large value. Figure 6 shows the measurement at the inner corner! This is a diagram showing the change in shape, starting from a certain distance (Bl in the diagram) before the spoon reaches a part of the corner, and the weight begins to increase and becomes a constant value.
From a certain distance II (H3 in the figure) before the end point of part of the corner, the amount to be removed begins to decrease and returns to the amount to be removed at the straight line machining portion.

Therefore, as explained above, especially in a part of the inner corner, the electrode side gap Gs increases as the distance L increases, and the shape after processing deteriorates significantly (FIG. 7).

Also, in the outside corner, the amount of blowing decreases, resulting in a 1! Since a decrease in electrode surface visibility [Gs occurs, the shape after processing similarly deteriorates at C.

[Problem that the invention seeks to solve]

Since the conventional wire-cut electrical discharge machining machine is constructed as described above, the wire electrode side surface Ifl gap is generated due to the increase in the removal amount, which occurs especially at corner portions! , and as a result, there were problems such as a significant deterioration in the accuracy of the shape after processing.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a wire-cut electric discharge machine that significantly improves the machining accuracy of a part of a corner.

[Means for solving problems]

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

[Effect]

The means for predicting the change in corner part removal amount in this invention is as follows:
Based on the information given in advance and the information indicating the machining position and state of the wire, a control device is operated to correct the change in the electrode side gap due to the change in the amount of cutting, thereby improving the machining accuracy at a part of the corner.

[Embodiments of the invention] - Hereinafter, one embodiment of the present invention will be described based on the illustrations and illustrations ζ.

In Fig. 1, (1) is a wire-shaped electrode, and (2) is! #
i workpiece, (3) is an X slider that moves the workpiece (2) in the horizontal direction in the figure, (4) is a Y slider that moves the workpiece (2) in the front and back direction in the figure, ( 5) is X7. A servo motor that drives the rider (3), (6) a servo motor that drives the Y slider (4), (7) a servo amplifier that supplies current to the servo motor (5), and (8) a servo motor that drives the servo motor (6). ), a serve amplifier that supplies current to (
9) is a processing power source that supplies a pulsed voltage between the wire-shaped electrode (1) and the workpiece (2), and αO is the power source that supplies the wire-shaped electrode (1) to the workpiece (1)
) and the workpiece (2) a detector for detecting the dark average machining voltage; 0 is a control device for controlling the servo amplifiers (7) and (8) based on the signal of the detector α1 and a predetermined Niprogram; ＠ is a discriminator that determines whether the machining position is moving in a partial arc around a corner or not.

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

As in the conventional example, the wire-shaped electrode (1) runs at a predetermined speed, and a pulse voltage is applied from the processing power source (9) between the wire-shaped electrode (1) and the workpiece (2). As a result, an electric discharge is generated between the wire-shaped electrode (1) and the workpiece (2).
The servo amplifier (7
) (8), a movement command signal is sent to the feed port 1, and from that signal i the servo motors (5) and (6) drive the X slider (3) and Y slider (4) to process the desired shape. The control device (b) detects the wire-shaped electrode (1) and the workpiece (2) by detecting the average voltage between the electrodes using the detector QG.
Drive the X slider (3) and Y slider (4) at an appropriate feed rate so that the machining gap is constant, and perform end face finishing several times after rough machining. MF! , to obtain surface roughness. As mentioned earlier, the shape accuracy after finishing machining is determined by the electrode side gap, and in order to perform high-precision shape machining, this t
It is important to keep the polar plane field constant.

During finishing machining, the discriminator (2) determines whether the current machining position is moving in a partial arc around a corner or not, and when the corner is moving in a partial arc, it sends a signal to operate the control device α4. . The control device α4 uses the signal received from the discriminator port to preset or set a new value for machining a part of the corner. Select the gain of the ffi servo, switch the gain of the inter-mole servo, and return to the original gain upon completion of corner machining.

For example, in the case of inside-corner machining, as explained earlier, the electrode side gap expands as the machining capacity increases, resulting in overcut. This prevents the machining speed from decreasing too much in some areas, and as a result, compensates for overcuts due to the machining integral effect.

These series of operations are performed by the operator using I! This is done automatically for all corner sections during machining without having to switch between the 4 gains of the servo between the armatures.

In the above embodiment, the control device f, the discriminator υ, and the arithmetic unit (
Although the example in which the giJ control device α4 is provided independently has been shown, if the same functions can be achieved, these two functions may be performed by a single control device. Further, in the above embodiment, an example was given in which the correction is performed only at a part of the inner corner, but by providing a second discriminator that discriminates whether the target corner is an inside corner or an outside corner, it is possible to
It is possible to perform corrections on both out corners.

〔Effect of the invention〕

As described above, according to the present invention, since a control means is provided to predict in advance the removal of ik'g in a part of a corner and to correct a change in the electrode side gap due to a change in removal amount, the problem that occurs in a part of a corner, etc. The amount taken? Since it is possible to prevent deterioration in machining accuracy due to changes in the area near the electrode side surface due to the change in shape, the machining accuracy in a part of the corner can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing wire-cut electrical discharge machining i according to an embodiment of the present invention, Fig. 2 is a block diagram showing a conventional wire-cut electrical discharge machining machine, and Fig. 8 shows the wire-shaped electrode and the covered material during finishing machining. Figure 4 is an enlarged view of the workpiece. Figure 4 is a diagram showing the relationship between removal amount and electrode side gap. Figure 5 is an enlarged view of the wire electrode and workpiece during inside corner finishing. Figure 6 is a part of the inner corner. Figure 7 shows the change in removal amount at the inner corner. In the figure, (1) is the wire-like pole, (2) is the workpiece, (3) is the X slider, (4) is the Y slider, (
5) (6) Lotus-bo motor, (7) (8) is servo amplifier, (9) is processing power supply, QG is detector, circle is control device, (2) is discriminator, side is computing unit, α4 is the control device.

Claims (2)

[Claims] (1) In a wire-cut electric discharge machine that generates electrical discharge by applying a voltage between opposing wire-shaped electrodes and the workpiece, and also moves the wire-shaped electrode and the workpiece relative to each other to perform processing, the machining position a first discriminator that determines whether the corner portion is moving in an arc or not;
A wire-cut electrical discharge machine characterized by being provided with a control device that switches the gain of a machining servo based on a signal from the discriminator. (2) It has a second discriminator that discriminates whether the target corner is an inside corner or an out corner, and the pole-to-pole servo is controlled by the signal from the first discriminator and the signal from the second discriminator described above. The wire-cut electric discharge machine according to claim 1, further comprising a control device for switching the gain of the wire-cut electric discharge machine.