JPH05116031A - Electric discharge machining device - Google Patents

Abstract

PURPOSE:To enable stable and efficient machining to be carried out even if machining is carried out with a large electrode. CONSTITUTION:An electric discharge machining device is provided with a memory 23 in which a large number of jump speed control patterns have been stored, a device 19 for detecting the position error between the actual movement of an electrode 1 and a movement command, a device 21 for calculating the electrode area from the position error, and a device 24 by which a jump speed control pattern corresponding to the electrode area is selected out of a jump speed control pattern group 23 for setting it in a jump control device 10. In such a constitution, the jump speed control pattern can be changed in accordance with the size of the electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machine for controlling a jump speed of an electrode, and more particularly to an electric discharge machine capable of setting a jump speed control pattern according to the size of an electrode. ..

[0002]

2. Description of the Related Art When electric discharge machining is performed, the accumulation of machining powder generated between an electrode and a work in a specific place leads to the concentration of electric discharge, which causes an electric discharge mark to deteriorate the machined surface. Inside, this processed powder must be eliminated as appropriate. The jump is to remove the machining powder between the poles by applying a voltage between the electrode and the workpiece during machining, and quickly pulling up and down the electrode by the voltage between the poles depending on the condition of the poles or the condition between the poles. ..

FIG. 4 is a block diagram showing a conventional electric discharge machine that performs such jump control, and FIG. 5 is a flow chart showing the flow of jump control. In FIG. 4, 1 is an electrode, 2 is a work, 3 is an inter-electrode voltage detection device that detects the voltage between the electrodes 1 and 2, and 4 is an inter-electrode servo control device that controls the inter-electrode servo. A memory that stores the voltage that serves as the reference when performing the gap servo, 6, 7 and 8 are constants that calculate the number of output pulses by multiplying the difference between the gap voltage and the reference voltage, and 9 is a constant time or according to the machining state. To output a jump signal, 10 is a jump control device for controlling the jump, 11 is a memory for accumulating the number of output pulses at the time of jump, and 12 is a speed control pattern fixed at the time of jump. Table, a jump pattern table in which jump speed, jump end position, jump speed deceleration position, jump deceleration speed, etc. are set, and 15 is a memory for storing the number of output pulses. 16 motor 1 the number of output pulses of the memory 15
An output device for outputting to 7, a motor 17 and an NC control device 30 for controlling a polar tube between the electrode 1 and the work 2 including the above-mentioned inter-electrode voltage detecting device 3 to the output device 16.

FIG. 6 shows the movement of the electrode during a jump when the horizontal axis represents time and the vertical axis represents distance. The wavy line 31 represents the electrode motion during machining, and the inclination of the straight line 32. Is the jump backward speed, the inclination of the straight line 33 is the jump forward speed, the inclination of the straight line 34 is the speed change speed after the jump speed is changed, the wavy line 35 is the movement of the electrode after the end of the jump, 41 is the jump start / retract position, and 42 is the jump amount. , 43 is a jump speed change position, and 44 is a jump end position.

FIG. 7 shows the relationship between the electrode 1 and the work 2 due to the high speed movement in the jump in the case of a large electrode, and FIG. 7A shows the electrode 1 when the electrode is moving at a low speed. (B) shows the state of the electrode 1 when the electrode 1 is advanced toward the workpiece 2 at high speed, 51 shows the pressure of the machining liquid existing between the electrodes, and (c) shows the electrode 1 at high speed. Is a state of the electrode 1 when separated from the work 2, 52 is a negative pressure of the machining liquid existing between the electrodes, and (d) is a state of the electrode 1 when the electrode 1 is tilted due to vibration or the like. There is.

Next, the operation will be described with reference to FIGS. First, the machining gap servo processing is performed during processing.
That is, in step 102, the electrode 1 and the work 2 are
The voltage between the electrodes is detected, and in step 103, an amount obtained by subtracting a reference voltage set in advance from the voltage is selected and multiplied by a constant according to the position of the electrode or the time from the occurrence of a short circuit, In step 104, the value is output as the number of output pulses to the motor 17 at regular intervals, and in step 105, the amount is integrated to form a servo backward pulse. When a jump is activated at regular intervals during machining, the gap servo processing is switched to the jump processing in step 101, and the servo backward pulse at that time is recorded as the jump start backward position in step 110.

The speed control during the jump is controlled by the data of the preset jump pattern table 12. In the jump pattern table 12, the amount of electrode retreat at the time of jump, that is, the jump amount, the jump retreat speed at the time of jump retreat, the jump forward speed at the time of jump forward,
There are jump end position, speed change position, speed change speed, etc.

When the jump is started, step 112
At step 113, the number of output pulses determined from the jump backward speed of the jump pattern table 12 is calculated, and the amount is added to the jump backward position and the servo backward position at step 113, and at step 114, step 11
The number of output pulses calculated in step 3 is attached to the motor 17 so as to output it in the backward direction, and is output to the motor 17 at regular intervals. In step 111, the backward position is the jump amount of the jump pattern table 12. Continue this process until they match. Here, in step 111, the jump backward position is the jump pattern table 12
If the number of pulses exceeds the jump amount in step 122, the number of pulses corresponding to the jump forward speed of the jump pattern table 12 is calculated in step 122, and in step 123, the number of pulses is subtracted from the jump backward position and the servo backward position accumulated in step 113. In step 124, the value of the jump forward speed of the jump pattern table 12 is attached to the motor 17 so as to output it in the forward direction, and is output to the motor 17 at regular time intervals. The process is continued until the velocity change position of 12 or less is reached. Here, in step 121, when the servo retract position subtracted in step 113 is less than or equal to the speed change position of the jump pattern table 12, in step 132, the number of output pulses according to the speed change speed of the jump pattern table 12 is set. Calculation, and in step 133, step 123
The output pulse number is subtracted from the jump retreat position and the servo retreat position, which have been subtracted in step 1, and in step 134, the value of the speed at the time of speed change of the jump pattern table 12 is set to the motor 1
7 is attached so that it is output in the forward direction, and is output to the motor 17 at regular time intervals. In step 131, the process is continued until the jump backward position is equal to or lower than the jump end position. Here, in step 131, when the retracted position is equal to or lower than the jump end position, the jump is terminated, and in step 141, the jump retracted position is cleared and switched to machining, and the gap servo processing from step 102 is performed. These processes are continued until the processing is completed in step 150.

Further, referring to FIG. 7, the state of the electrode at the time of jumping when processing with a large electrode will be described. In (b), when the electrode 1 approaches the workpiece 2, the electrode 1 is caused by the pressure 51 of the machining fluid existing between the electrodes.
Is deformed, and in (c), the electrode 1 is deformed due to the negative pressure 52 of the machining liquid existing between the electrodes when the electrode 1 is pulled up with respect to the work 2, and in (d), the electrode 1 is changed to the work 2. When the axis of the electrode 1 is tilted due to vibration of the mechanical system or the like when approaching, the bottom surface of the electrode 1 also tilts. These phenomena are particularly remarkable when the electrodes are large.

[0010]

Since the conventional electric discharge machining apparatus is constructed as described above, in the case of a large electrode (for example, the cross-sectional area of the electrode is about 1000 mm ² or more), the machining liquid existing between the electrodes is large. The deformation of the electrode due to the negative pressure or the positive pressure of the electrode, or the inclination of the electrode due to the vibration increases. Therefore, if the same control as that of an electrode having a small area with a small influence is performed, there is a case where a part of the electrode is very close to or in contact with the electrode at the end of the jump. When the jump is completed in this state, the machining is switched to, and the machining is controlled by the machining gap servo, a retraction command is output to the electrodes because the machining gap is in a short-circuited state, and a position where discharge is possible again after the retraction. The time to return to is wasted. In addition, when the jump is finished while the electrode is in contact with the work in this way, when the electrode comes into contact with the work by the jump, hit the work through the machining powder in the machining fluid. However, there is a problem that the work may be damaged and the work may be damaged.

The present invention has been made in order to solve the above problems, and by setting a jump speed control pattern according to the size of an electrode even when electric discharge machining is performed using a large electrode. It is an object of the present invention to obtain an electric discharge machining device capable of stable and efficient machining.

[0012]

In order to achieve the above object, the electric discharge machining apparatus according to the first invention is capable of changing the pattern of jump speed control according to the size of the electrode. In the one provided with an inter-electrode servo control device for performing inter-electrode servo control between the electrode and the work, and a jump control device for causing the electrode to perform a jump operation at regular time intervals or according to a machining state, A jump pattern table group in which a large number of jump speed control patterns are stored, a position error detection device for detecting a position error amount between a movement command and an actual movement amount for the electrode during a jump operation, and an electrode based on the detected position error amount. Select the electrode area calculation device for calculating the area and the jump speed control pattern corresponding to the calculated electrode area from the jump pattern table group It is obtained by a jump pattern setting device for setting the Jump controller.

The electric discharge machining apparatus according to the second invention is
An adaptive control device for setting an optimal jump speed control pattern is provided in place of the jump pattern table group, and the adaptive control device calculates the electrode area calculated by the electrode area calculation device and the jump operation time. The optimum jump speed control pattern is determined from the machining state, the movement of the electrode, etc., which can be read from the movement command of 1. and set in the jump control device.

[0014]

According to the size of the electrode, a position error occurs between the actual movement amount of the electrode and the movement command, and the position error amount is roughly proportional to the electrode area. Therefore, since the electrode area can be calculated by detecting the position error amount, the jump speed control pattern corresponding to the electrode area is selected from the jump pattern table group in which many jump speed control patterns are stored in advance. Then, by setting the jump control device, the electrodes perform a jump operation in a jump speed control pattern according to the electrode area.

In addition, the adaptive control device determines whether the jump speed control pattern is appropriate or not based on the electrode area calculated by the electrode area calculation device and the machining state and the movement of the electrode that can be read from the movement command during the jump operation. The parameter of the jump speed is changed in an appropriate direction, and the optimum jump speed control pattern is determined and set in the jump control device in the direction in which the processing efficiency is further increased, that is, in the direction in which the jump time is shortened.

[0016]

【Example】

Example 1. 1 is a block diagram showing an electric discharge machine according to a first embodiment of the present invention. In the figure, reference numerals 1 to 17 are the same as those in FIG. Reference numeral 18 is an encoder, 19 is a position error detecting device that calculates a position error amount from the actual movement amount of the encoder 18 and the output pulse amount of the memory 15, and 20 is a memory that stores the position error amount calculated by the position error detecting device 19. , 21 is an electrode area calculation device for calculating the machining electrode area from the position error amount of the memory 20, 22 is a memory for storing the machining electrode area, 23 is a jump pattern table group for storing a large number of jump speed control patterns, and 24 is a memory 22.
A jump speed control pattern suitable for the machining electrode area of the memory is selected from the jump pattern table group 23, and the memory 12
Jump pattern setting device to be set in the jump pattern table of No. 30, reference numeral 30 denotes the voltage between contact detection device 3 and the output device 1
The NC control device controls the gap between the electrode 1 and the work 2 including the position error detection device 19 to the jump pattern setting device 24.

Next, the operation of the first embodiment will be described. The gap servo processing and the jump processing of the first embodiment are performed according to the flowchart of FIG. 5 as in the above-described conventional example, and therefore the description thereof is omitted here. In the first embodiment, the NC servo control device 4 is used in the NC control device 30.
While controlling the gap between the electrode 1 and the work 2 by the jump control device 10, a jump speed control pattern suitable for the machining electrode area stored in the memory 22 is set by the jump pattern setting device 24 in the jump pattern table group 23. And is set in the memory 12 when the jump activation device 9 has not activated the jump. Therefore, in the above jump processing, the jump control is performed according to the flow from step 110 to step 141 of FIG. 5 by the data of the jump speed control pattern preset in the memory 12.

That is, until the machining is completed, the jump speed is set by the jump pattern setting device 24 in parallel with the control of the gap servo by the gap servo control device 4 and the jump of the electrode by the jump control device 10. Set the control pattern.

The machining electrode area is calculated by the electrode area calculating device 21 by multiplying the position error amount stored in the memory 20 by a certain constant. When the electrode becomes large, a position error amount occurs between the actual movement amount and the output pulse amount of the memory 15 as a movement command due to the positive pressure or the negative pressure of the machining liquid applied to the electrode 1. This position error amount is roughly proportional to the electrode area, that is, the maximum cross-sectional area of the electrode, and the machining electrode area can be obtained by appropriately selecting a constant. Therefore, the encoder 18 attached to the motor 17 detects the actual movement amount of the electrode 1, and the difference between the actual movement amount and the output pulse amount of the memory 15 is calculated by the position error detection device 19 and stored in the memory 20. As a result, the sectional area of the electrode 1 being processed can be calculated by the electrode area calculation device 21 as described above. The machining electrode area calculated in this way is stored in the memory 22. Then, as described above, the jump pattern setting device 24 selects the jump speed control pattern corresponding to the machining electrode area of the memory 22 from the jump pattern table group 23 and sets it in the memory 12. Therefore, the jump operation of the electrode 1 can be controlled by the jump speed control pattern corresponding to the machining electrode area.

[0020] FIG. 2 shows an example of the jump pattern table group, in this example, a 100 mm ² or less by the maximum cross-sectional area of the electrode, and 100～2500Mm ^2, 25
The jump backward speed, the jump forward speed, the jump end position, the speed change position, and the speed at the time of change are defined respectively in three ranges of 00 mm ² or more, and thus the jump speed control pattern according to the machining electrode area is set. Are stored in the memory 23 in large numbers. The jump amount is usually about several hundred μm to 2000 μm.

Example 2. Next, FIG. 3 shows a second embodiment of the present invention.
2 is a block diagram showing an electric discharge machining apparatus according to the present invention. In the figure, reference numeral 25 denotes an adaptive control device, and this adaptive control device 25 has a machining electrode area of the memory 22 and a servo state of the electrode which can be read from an output pulse of the memory 15, that is, a machining state. The optimum jump speed control pattern is determined from the movement of the electrodes and the like and is set in the memory 12. An adaptive control device 25 is provided instead of the jump pattern table group 23 of the first embodiment, and the output pulse of the memory 15 is input to the electrode area calculation device 21 and the adaptive control device 25. Other configurations are the same as those in the first embodiment.

In the NC control device 30 of the second embodiment, while the inter-electrode servo control device 4 and the jump control device 10 perform the inter-electrode control of the electrode 1 and the work 2, the adaptive control device 25 stores the memory 20 in the memory 20. Whether the jump speed control pattern is appropriate or not is determined from the position error, the machining electrode area of the memory 22, the servo state of the electrode read from the output pulse of the memory 15, that is, the machining state, the movement of the electrode, and the like. Whether the jump speed control pattern is appropriate or not is determined by whether the machining is stable or unstable. If this judgment is unsuitable, the jump speed parameter is changed in the appropriate direction, and if it is suitable, the optimum jump speed control pattern is determined in the direction in which the machining efficiency is further increased, that is, the jump time is shortened. Then, it is set in the memory 12. Therefore, the above-mentioned jump processing is performed according to the optimum jump speed control pattern data set in the memory 12 in step 1 of FIG.
The jump control is performed according to the flow from 10 to step 141.

In the above embodiments, as the jump pattern table, the electrode retreat amount at the time of jump, that is, the jump amount, the jump backward speed at the jump backward, the jump forward speed at the jump forward, the jump end position, the speed change position. Although the speed at the time of speed change is increased and the speed control at the time of jump is performed by these, any number of these parameters may be possessed, and a function having the position of the electrode, time and the like as parameters may be used.

[0024]

As described above, according to the present invention, it is possible to perform stable and efficient machining because even a large electrode can change the speed in the vicinity of the work at the time of jump, the jump end position, etc. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a jump pattern table group according to the first embodiment.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a conventional electric discharge machine.

FIG. 5 is a flowchart showing the flow of jump control according to the present invention and the conventional jump control.

FIG. 6 is a diagram showing the movement of electrodes during a jump.

FIG. 7 is a diagram showing a phenomenon that occurs between an electrode and a work due to high-speed jump movement when a large electrode is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 electrode 2 work 4 servo control device between poles 10 jump control device 12 jump pattern table (memory) 19 position error detection device 23 jump pattern table group (memory) 24 jump pattern setting device 25 adaptive control device

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[Procedure amendment]

[Submission date] January 17, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012]

In order to achieve the above object, the electric discharge machining apparatus according to the first invention is capable of changing the pattern of jump speed control according to the size of the electrode. In the one provided with an inter-electrode servo control device for performing inter-electrode servo control between the electrode and the work, and a jump control device for causing the electrode to perform a jump operation at regular time intervals or according to a machining state, A jump pattern setting device for setting a jump speed control pattern corresponding to the area of the electrode in the jump control device is provided.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

The electric discharge machining apparatus according to the second invention is
In addition to the electric discharge machining apparatus according to the first aspect of the present invention, a position error detection apparatus that detects a position error between a movement command and an actual movement amount for the electrode during a jump operation, and an electrode area is calculated from the detected position error amount. And an electrode area calculation device. Further, an electric discharge machine according to a third aspect of the present invention is the same as the electric discharge machine according to the first aspect of the present invention, with a jump pattern table group in which a large number of jump speed control patterns are stored, instead of the jump pattern setting device. A jump pattern setting device for selecting a jump pattern corresponding to the electrode area from the jump pattern table group and setting it in the jump control device is provided. The electrical discharge machining apparatus according to a fourth aspect of the present invention includes an adaptive control device that sets an optimum jump speed control pattern, instead of the above jump pattern table group. The optimum jump speed control pattern is determined from the machining state, the movement of the electrode, and the like which can be read from the movement command during the jump operation, and is set in the jump control device.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

[Function] Since the jump pattern can be changed according to the size of the electrode, it is possible to prevent the electrode from being deformed by the pressure of the machining fluid or the vibration of the electrode which is caused by the high jump speed when machining with a large electrode. You can Further, depending on the size of the electrode, a position error occurs between the actual movement amount of the electrode and the movement command, and the position error amount is roughly proportional to the electrode area. Therefore, since the electrode area can be calculated by detecting the position error amount, the jump speed control pattern corresponding to the electrode area is selected from the jump pattern table group in which many jump speed control patterns are stored in advance. Then, by setting the jump control device, the electrodes perform a jump operation in a jump speed control pattern according to the electrode area.

Claims (2)

[Claims] 1. An electric discharge comprising: an inter-electrode servo control device for performing inter-electrode servo control between an electrode and a work; and a jump control device for causing the electrode to perform a jump operation at regular time intervals or according to a machining state. In the processing device, a jump pattern table group in which a large number of jump speed control patterns are stored, a position error detection device that detects a position error amount between a movement command for the electrode and an actual movement amount during a jump operation, and the position error. An electrode area calculation device for calculating an electrode area from the position error amount detected by the detection device, and a jump speed control pattern corresponding to the electrode area calculated by the electrode area calculation device are selected from the jump pattern table group. And a jump pattern setting device which is set in the jump control device. 2. An electric discharge comprising an inter-electrode servo control device for performing inter-electrode servo control between an electrode and a work, and a jump control device for causing the electrode to perform a jump operation at regular time intervals or according to a machining state. In a processing device, a position error detection device that detects a position error amount between a movement command and an actual movement amount for the electrode during a jump operation, and an electrode that calculates an electrode area from the position error amount detected by the position error detection device Area calculation device, a machining state that can be read from the movement command at the time of the jump operation and the electrode area calculated by the electrode area calculation device,
An adaptive control device for determining the optimum jump speed control pattern from the movement of the electrodes and setting the jump control device,
An electric discharge machine comprising: