JPH10309630A - Electric discharge machining control method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten machining time by computing and automatically setting a value of each set condition of jumping motion in accordance with each data value at a current machining position at the time of detection and discrimination when a working command signal of the jumping motion is output and starting opening work of the jumping motion of the set condition. SOLUTION: A jumping motion control part 18 has a fuzzy inference part 19 of a jumping motion condition and a starting judgement part 20 of jumping motion. The starting judgement part 20 of the jumping motion judges whether to simultaneously an inference practicing command in the fuzzy inference part 19 and a starting command of the jumping motion in parallel by judging them from a changing signal of a voltage pulse supply condition of voltage pulse cessation width output to a machining voltage pulse supply electric power source 10, etc., by a machining state discrimination signal from a machining state detection discrimination device 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for generating an intermittent discharge between opposing workpieces with a small gap in a machining fluid by using a rod-shaped or full-shaped electrode. In electric discharge machining of engraving, etc., which performs drilling, engraving, etc. on the workpiece, the reciprocating movement of the electrode or the workpiece relative to the relative separation and separation in addition to the servo feed for gap maintenance control during machining More specifically, the present invention relates to an electric discharge machining control method and an electric discharge machining method for improving machining efficiency by minimizing the jump motion for performing machining while performing a so-called jump motion intermittently.

[0002]

2. Description of the Related Art There are already various types of modes of operation and control of the above-mentioned jumping motion, and typical ones are a repetition period and a stroke (jump amount, that is, a separation distance) of the jumping motion. , And various types of automation are available, such as a mode in which the operator selects and sets it and switches it as necessary. That is, for example, one or more jump conditions are set and set, such as setting and setting a stroke of a jumping motion, and the detection and determination of the processing state by the processing state detecting device deteriorates beyond a certain level (for example, processing waste or the like). When the normal discharge occurrence ratio is reduced to a predetermined value or less due to the accumulation or excessive concentration of), the jump of the set stroke is performed, and a combination of a plurality of large and small jump strokes and a processing time (period) when approaching. In order to respond to the increase in the depth of the machining hole, the elapse of machining time, or the deterioration of the machining state in the machining gap, the separation distance of the reciprocating motion is set A device that sequentially increases and decreases the proximity processing time during proximity in a short period (for example, Japanese Patent Publication Nos. 54-7,998 and 56-56).
In recent years, the stability of the electric discharge machining state and its change rate are calculated from the values of the voltage and current detected from the gaps and their waveform characteristics, and the stability and the change rate of the stability are calculated. And outputs the increment of the jump period and the increment of the jump distance by fuzzy inference to change and control the jump period and the distance (see JP-A-2-303,720).

[0003]

The jump operation during the electric discharge machining as described above involves the followings: material, combination, dimensions, shape, electrode machining area, selectively set electric machining conditions, The shape of the processing hole, the current depth of the processing hole, the conditions for supplying the processing liquid to the processing gap, the flow conditions of the processing liquid due to the increase in the depth of the processing hole according to the progress of processing, and the setting processing gap Depending on the servo control conditions of the maintenance, etc., each value of the jump stroke, the processing time or cycle at the time of proximity, the speed of reciprocating movement, particularly the feed speed at the time of separation or proximity, and each value when combined, There is an appropriate value, it is almost difficult to adjust to the optimum value, and even if a certain amount of adjustment can be made, the depth of the hole, the area and the shape of the hole will change as the machining proceeds Then, the appropriate value of each jump condition changes From Rukoto, Te is at the actual machining conventionally hardly occur arcing during machining, the electrode-
The selection and setting of the conditions on the safety side that do not cause shaking on the workpiece are performed. Therefore, in the conventional machining, the machining dead time during machining by performing the jump control (when the gap state such as a normal gap length between the electrode and the workpiece is maintained, the repetition rate is close to a predetermined repetition rate. Period during which the state discharge does not occur repeatedly)
For this reason, the average processing speed is greatly reduced from the estimated or theoretical processing speed based on the set processing conditions. Therefore, according to the present invention, the jumping motion during electric discharge machining can be quantitatively and qualitatively controlled by controlling the number of times, frequency, amount of jump, movement speed, etc. without causing the operator to perform operations such as setting and switching. The object is to provide an optimum and minimum necessary, to improve the processing efficiency, and to shorten the processing time.

[0004]

SUMMARY OF THE INVENTION The above-mentioned object of the present invention is as follows.
(1) A machining liquid is interposed in a minute machining gap formed between a machining electrode and a workpiece to face each other, and is intermittently applied with a pause while maintaining the machining gap by servo control feed. An electric discharge machining performed by electric discharge generated by a voltage pulse, wherein the original gap position after opening of the machining gap is different from the servo control feed for maintaining the gap to an electrode or a workpiece during machining. In an electric discharge machining control method in which machining is performed while performing a jump motion approaching to the vicinity when an operation command signal is input, at least the separation distance, which is a setting condition of the jump motion, is an electrode at a current machining position. From the processing conditions including the data of the processing area and the depth of the processing hole, the moving speed including the relative moving speed characteristic of the separation and proximity, which is another setting condition of the jumping motion, is at least the above-mentioned. It is configured so that it can be automatically set by fuzzy inference from the processing area of the electrode at the current processing position and the processing conditions including the data of the processing gap length, and the voltage pulse is applied to the processing state of the processing gap during processing. When the operation command signal of the jumping motion is output by the detection discrimination of the period to be performed, the value of each setting condition of the jumping motion is automatically calculated based on each data value at the current machining position at the time of the detection discrimination. In addition, the above-described electric discharge machining control method for activating the opening operation of the jumping motion under the set conditions is achieved.

Another object of the present invention is to provide (2) a machining liquid interposed in a machining gap formed between a machining electrode and a workpiece while facing each other, and maintaining the machining gap by servo control feed. This is electric discharge machining in which machining is performed by electric discharge generated by a voltage pulse intermittently applied with a pause, and the machining is performed on an electrode or a workpiece different from the servo control feed during machining. After the opening of the gap, machining is performed while a jumping motion approaching to the vicinity of the original gap position is performed when an operation command signal is input, and the voltage pulse is paused by the machining state detection signal during machining by servo control feed. In the electric discharge machining control method, the time is controlled to increase sequentially according to the deterioration of the machining state, and the control is performed while performing the pause time control so as to gradually decrease to a set value according to the normalization. The separation distance, which is the setting condition of the stepping motion, is based on at least the processing area including the electrode processing area and the hole depth data at the current processing position, and the separation distance, which is another setting condition of the jumping motion. The moving speed including the relative moving speed characteristic of at least the processing area of the electrode at the current processing position and the processing conditions including the data of the processing gap length can be automatically set by fuzzy inference, respectively, during the processing. The value of each setting condition of the jump motion is calculated based on the respective data values at the current machining position at the time of the pause time control as a signal that the pause time has reached a predetermined increase control level by the pause time control. The above-described electric discharge machining control method, which is more preferably and surely achieved by automatically setting and activating the separating operation of the jump motion under the set conditions, is performed. .

It is another object of the present invention to (3) increase the discharge repetition frequency of the machining gap from the position immediately before the machining gap, which is the end of the started jumping motion, returns to the position at the start of jumping. 3. The method according to claim 1, wherein the detection is repeatedly performed, and while the detection discharge repetition frequency is increasing, the detection and determination of the processing state of the processing gap for generating and outputting the operation command signal of the jumping motion is suppressed. The electric discharge machining control method described in (1) can achieve better.

Another object of the present invention is to (4) calculate the average machining voltage of the machining gap from the position immediately before the machining gap, which is the end of the started jumping motion, returns to the position at the start of the jump. The jump motion is activated while the detected average machining voltage is equal to or higher than a reference voltage for servo control feed for machining or a half of a non-negative voltage of a machining voltage pulse. The electric discharge machining control method according to claim 1 or 2, which suppresses the detection and determination of the machining state of the machining gap for generating and outputting the command signal, can be achieved even better.

Another object of the present invention is to provide: (5) a machining liquid interposed in a minute machining gap formed between a machining electrode and a workpiece to face each other, and the machining gap is maintained by servo control feed. In a control apparatus for electric discharge machining, which performs machining by electric discharge generated by a voltage pulse applied intermittently with a pause time, a different relative to the servo control feed to the electrode or the workpiece during machining. A jump drive control means for performing a jumping movement to approach the vicinity of the original gap position after the opening of the machining gap when an operation command signal is input, and the voltage pulse based on a machining state detection signal during machining by servo control feed. A voltage pulse supply control means of the voltage pulse supply power supply, which controls the intermission time to sequentially increase according to the deterioration of the machining state, and controls to decrease gradually to a set value according to normalization. A jump motion control unit and a fuzzy inference unit of the jump motion condition and a jump motion of the activation determination section, the fuzzy inference unit of the jump motion condition,
Infer the separation distance of the jumping motion from the depth data of the machining hole based on the current feed position detection signal of the electrode and the current machining area data obtained from the input machining condition data or machining progress state and infer the jump movement separation distance. A jump amount inference unit that outputs a signal to the jump drive control unit; and a processing of the jump motion from the processing area data and the input processing condition data or the processing gap length data obtained from the current and past feed position detection data of the electrode. A jump movement speed inference unit that outputs a jump movement speed signal including a relative movement speed characteristic to the jump drive control unit; and at least a jump signal and a jump movement speed based on a determination signal from at least the jump motion activation determination unit. Execute the inference in the inference unit and output the jump amount and the moving speed signal to the jump drive control means. Both have a fuzzy inference unit control means for outputting a start instruction signal of the jump motion to jump drive control means, is further activation determination of the jump motion,
When the output state of the control signal of the pause time control output to the voltage pulse supply power supply by the voltage pulse supply control means exceeds a predetermined level of the pause time control pattern set as input, a determination signal of an inference command is output. This is achieved by the electric discharge machining control device described above.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a block diagram showing a schematic configuration of an apparatus for implementing an electric discharge machining control method according to the present invention, wherein 1 is a machining electrode, and 2 is a workpiece. Reference numeral 3 denotes an xy axis driving servomotor 3 in which a processing tank 4 for housing a stage (not shown) on which the workpiece 2 is mounted is installed.
The movable cross table 5 having x and 3y is supplied and stored from a working fluid circulation supply device (not shown) so as to keep the working gap in the Z-axis direction between the electrode 1 and the workpiece 2 immersed in the working fluid. The processing fluid 6 in the processing tank 4 feeds the electrode 1 to the workpiece 2 by the servo control in the Z-axis direction, and when a jump motion command is output, the motion control signal causes the Z-axis to move from the current processing position to the Z-axis. The Z-axis feed servo motor, which also performs a so-called jumping drive feed for returning the electrode 1 to the vicinity of the original machining gap position after raising and separating the electrode 1 by a predetermined amount to the vicinity of the original machining gap position, 7 Is a feed position detecting device such as an encoder which detects the current feed position of the electrode 1 by the motor 6 at the normal tip, and 8 detects the ascending and descending feed speed of the electrode 1 by the motor 6. Rotational speed detection device speed indicating generator, etc., or the encoder 7 or the like because there can be also used, 9 is a driving device of the servo motor 6.

Reference numeral 10 denotes a machining voltage pulse power supply which is connected in parallel between the electrode 1 and the workpiece 2 and repeatedly applies a rectangular wave-shaped voltage pulse after a pause to generate an intermittent discharge. Voltage pulse supply control means for controlling the voltage pulse supply conditions of the pulse supply power supply 10, and mainly the above-mentioned inter-voltage-pulse pause time conditions during processing, and 12 processes the processing state in the discharge gap between the electrode 1 and the workpiece 2. A voltage, a current, or an impedance in an average gap or during a discharge pulse, or an AC component such as a high frequency superimposed on the gap is detected, and a machining state determination signal is detected by the power pulse supply control unit 11 and the machining. A machining state detection and discrimination device that outputs servo control feed and jump drive control means 13 and the like, a display device 15 such as a CRT, an input device 16 such as a keyboard, and the like. A computer-controlled controller constituting a numerical control or other setting control device for an electric discharge machine having a storage information reading device 17 or the like of an external storage medium such as paper, magnetic tape, FD, or CD; The jump motion control unit includes a fuzzy inference unit 19 and a jump motion start determination unit 20.

The fuzzy inference unit 19 of the jumping motion control unit 18 drives the drive unit 9 such as a motor driver in accordance with a command signal from the machining servo control sending unit of the machining servo control sending and jump drive control unit 13. The signal (D) of the feed electrode position of the machining electrode 1 and the depth data of the machining hole by the motor 6 operated by the motor 6 is input from the position detecting device 7 via the control sending means 13 and the machining electrode 1 The signal (S) of the machining area data at the current machining hole depth position is obtained from the initial setting, input machining conditions and machining data in the control device 14 as shown in the figure, or mainly the electrical setting machining conditions. The amount of jump (separation distance of the jump motion) is inferred from the relationship between the machining feed speed per unit time or the machining feed amount per unit time according to the set machining conditions, and A jump amount inference unit 19A for outputting an amount signal to the jump drive control means 13, a processing area data signal (S) of the processing electrode 1 and a processing gap length data signal (G) as shown in FIG. Obtain as the discharge gap length data determined by the initial setting and input machining conditions, or the depth of the deepest machining hole and electrode tip position estimated from various machining data up to now, and the current position detection device Inference of the jump speed (moving speed including the relative moving speed characteristics of the separation and proximity) from the signal (G) of the processing gap length data obtained from the detection data of the electrode tip position obtained from 7 and the like. A jump speed inference unit 19B for outputting a jump speed signal to the jump drive control means 13; a signal of input selection setting processing condition data from the control device 14; Cross section 2
Fuzzy inference unit control means for executing the inference of each of the inference units 19A and 19B in the fuzzy inference unit 19 according to the judgment signal from 0 and outputting a jump motion start command signal to the jump drive control means 13. . Further, the jump motion start-up judging unit 20 outputs a voltage such as a pause between voltage pulses which the voltage pulse supply control means 11 outputs to the machining voltage pulse supply power supply 10 according to a machining state discrimination signal from the machining state detection and discrimination device 12. A pulse supply condition change signal, and preferably further from the control device 14,
The inference execution command and the jump motion start command in the fuzzy inference unit 19 are determined mainly from the processing condition data relating to the voltage pulse supply control condition, and it is determined whether or not to output simultaneously in parallel. When a jump motion is being executed by the jump drive control means 13, the signal being executed is input as feedback so that another jump motion is not started by being overlapped with the jump motion being executed. This is to stop the start determination.

In the electric discharge machining, built-in machining conditions of the control device 14, machining data, and various machining programs are stored in the electric discharge machining.
Depending on the electrode 1 to be used, the material, dimensions, shape, type of processing, target surface roughness, target dimensions / accuracy, and other processing purposes input from the input device 16 or the external information reading device 17. A logical operation is performed to obtain a processing condition of the setting control, and a voltage or a discharge pulse such as an on-time or a discharge time of a voltage pulse or a discharge pulse, the pause time, and a discharge pulse amplitude of the discharge pulse is supplied to the processing voltage pulse supply power supply 10. The condition, the voltage pulse supply control means 11 includes a waveform such as a rising characteristic of a discharge pulse, a cut-off condition from the middle of the discharge pulse, a control condition or a control pattern for increasing / decreasing the pause time, and the like. The machining servo control feed and jump drive control means 13 includes a servo reference voltage, a servo drive speed, a jump amount of jump drive control, a jump moving speed and a speed characteristic. Data such as input and set, and the Z
Driving device 9 for shaft servomotor and machining state detection / determination device 1
2 and the like as necessary or depending on the configuration, for example, a moving speed, a condition for switching between servo control and jump motion,
The timing or the discrimination level of the machining state, the response sensitivity, the discrimination processing conditions and the like are selectively set, and the jumping motion control unit 18 exchanges the various data and conditions described above for the electric discharge machining. It shifts to execution. In FIG. 1 and the description, machining in a state in which a relative rocking motion is applied in a direction perpendicular to the facing direction between the electrode 1 and the workpiece 2 by drive control of the xy-axis servo motors 3x and 3y of the cross table 3 And processing by jumping motion to drive and control the three-dimensional path, recovery and processing of the processing liquid 5 in the processing tank 4, configuration and operation of recirculation supply by filtration, and rough processing from the electrode 1 and the workpiece 2 to finishing processing The processing for the processing by sequentially switching the plurality of processing steps as described above is omitted.

The electric discharge machining gap between the electrode 1 and the workpiece 2 is
The no-load voltage of the voltage pulse output from the machining voltage pulse power supply 10 is such that a high-voltage auxiliary pulse power supply or the like is not used. For hydrocarbon mineral oil,
From the relationship of the dielectric breakdown voltage, when the gap-interposed working fluid is clean, the gap length is about 3 μm. However, when electric discharge is performed in the gap, the processing chips of the workpiece 2 are removed in the working fluid in the gap.
Since the consumable pieces of the electrode 1 and the product pieces generated by the decomposition, burning, carbonization, etc. of the working fluid are interposed, the working gap length is widened, and the working gap length during normal electric discharge machining is the same as the dielectric breakdown gap. Processing is performed about 10 times the length. Then, the electric discharge machining in such a machining gap is carried out by using some liquid from the machining waste generated by the discharge pulse generated by the machining voltage pulse supplied at a high frequency and the machining gap in which the electric discharge machining is performed. Due to forced or semi-forced flow and physical diffusion phenomena, the amount of machining waste flowing out of the machining gap together with some machining fluid is almost balanced, and machining in the machining fluid in the machining gap is performed. When the concentration of dust and the like is maintained within a substantially predetermined range, machining is performed between the electrode 1 and the workpiece 2 in a normal discharge state maintained at the machining gap length. The advanced machining feed is given by the rotation of the motor 6, and the machining proceeds.

However, the amount of machining debris generated by the discharge of the supply voltage pulse is compared with the amount of machining debris which is discharged from the machining gap to the outside of the gap due to physical phenomena or electric discharge together with the interposed machining fluid. The processing conditions, mainly the electrical conditions such as voltage pulses, are set so that the renewal liquid flow acts on the processing gap by any means as described above. Alternatively, it is necessary to cause the suction, agitation, and discharge actions by the pump action by the above-mentioned jumping motion to keep the concentration of the processing chips in the processing gap at a predetermined value or less. Depending on the type, the purpose of processing, etc., the machining fluid flow may not be able to act uniformly on the machining gap, or it may not be able to act on it. From where smooth elimination becomes difficult, the control of the concentration of such processing refuse by the generation processing refuse such emissions in the machining gap in which employed, application of the jump motion is important. That is, as control of machining conditions and the like corresponding to the machining state of the machining gap in electric discharge machining, responses and voltage pulse supply control (11), servo control feed (13), and jump drive control (13) are performed in this order. When the processing state detection / determination device 12 detects the deterioration of the processing state or the like, or when the deterioration state exceeds a certain level, the voltage pulse supply control means 11 is first activated by the processing state detection / determination device 12 from a place where much longer time is required by the corresponding processing. The conditions of the voltage pulse supplied by the machining voltage pulse supply power source 10, for example, the pause between voltage pulses,
The control operation will be performed in response to the time speed of μS so that the processing average current is reduced and the processing load is reduced.

In this case, the machining is continued in a state where the machining load is reduced by a predetermined amount by the control operation as described above. If the signal 12 continues to repeatedly output a signal due to the detection of the deterioration state of the machining state, the machining is continued in that state, and the servo control feed and jump drive control means 13 waits until the responsive time elapses. Mean 13
And the voltage pulse supply control means 11 is applied to the machining voltage pulse supply power supply 10 over two or more stages until the response time of the means 13 elapses. The conditions of the supply voltage pulse reduce the processing load in multiple stages one after another.For example, the pause between the voltage pulses is set according to the material combination of the electrode / workpiece, the processing shape and size, the type of processing, and the like. It is not necessary to shift to the control operation of the servo control feed / jump drive control means 13 by changing the control one after another such as twice, four times, eight times, 128 times, etc. of the time. It may be a control type or other desired mode of supply condition control of the voltage pulse. The control of the supply conditions of the machining voltage pulse such as the cut-off in the middle of the discharge pulse and the control of increasing the magnification of the inter-pulse pause time as described above eliminates machining dust generated by machining. Damage to electrodes / workpieces due to the occurrence and repetition of arc-like defective discharges when the deposition state reaches a certain level due to the deterioration of conditions and environment, and the concentration of generated discharges at the relevant locations (concentrated discharge) In order to prevent marks, discharge spots, and the like, machining is performed with control that does not significantly change machining performance and has the fastest response, and then machining is performed under detection and determination of a discharge state in machining under the control conditions. The normal operation is repeated until the response by the servo control.

In the above-mentioned case, the output of the discrimination signal by the detection and discrimination of the machining gap by the machining state detection discrimination device 12 is performed during a period in which a plurality of machining voltage pulses are applied by the power supply 10, for example, when each successive voltage is applied. Within the period in which 2 to 100 pulses or predetermined sampling voltage pulses are applied, the voltage, current, or impedance level at the average of the machining gap or during the discharge pulse, or the high frequency superimposed on the same It is discriminated and output by detecting the state of the component or detecting the state of the no-load time until the start of the discharge of each voltage pulse, and the output is continuously repeated or the period of a predetermined plurality of voltage pulses is outputted. Is repeated and sent to the voltage pulse supply control means 11 and the machining servo control feed and jump drive control means 13,
The control execution signal is output after processing such as determination. Then, the jumping motion activation determining unit 20 may determine the jumping motion introduction and activation based on the frequency or the number of the discrimination signal output from the machining state detection discriminating means 12.

When the machining state detection / judgment device 12 sends a judgment signal to the machining servo control sending means 13 indicating that the gap state is bad, that an arc discharge has occurred, or that the machining servo control sending means 13 is in a concentrated discharge state, etc. Depending on the frequency of occurrence and the content of the signal, when the response time of the means 13 has elapsed since the start of the supply of the determination signal to the servo control sending means 13, if the determination signal is still being sent, With the signal from the servo control feeding means 13, the motor 6 starts rotating, the electrode 1 is retracted (elevated), separated from the workpiece 2, the gap is widened, and the generated discharge is normalized. The moving distance for raising and lowering the electrode 1 by this servo control feed is usually as small as several tens of μm or less. Although the working fluid is sucked into and discharged from the processing gap, the moving speed of the raising and lowering is slow. Unless the machining hole is too shallow, products such as machining chips are rarely discharged out of the machining gap and return to a normal discharge state. And does not return to a normal discharge state due to a concentrated discharge or the like. It is necessary to discharge the products such as machining chips from the machining gap and to reduce the concentration of machining chips in the inclusions in the machining gap to a predetermined value or less. It is necessary to perform the operation of jetting the machining fluid, giving a jumping motion, or discharging the machining debris out of the machining gap by combining them, etc. in such a case. Assuming that exercise is necessary, the user should perform a jump exercise under necessary conditions (jump amount and jump moving speed).

FIG. 2 is a graph of one embodiment for explaining the operation of such a jumping motion. The vertical axis represents the jump amount and the separation distance L, and the horizontal axis represents the time t. The broken line P indicates the position of the temporal jump movement. Ll and Ls on the vertical axis are the positions of the maximum and minimum gaps under the servo control feed, and are assumed to be at the position of Lm on average. Lp is the expected jump highest position, and Lj is the expected jump amount. At time t1, the processing surface forming the processing gap on the tip end side of the electrode 1 is at the position P
1, i.e., assuming that it is at the position Lm where the average gap length is formed, a judgment signal of a jump command is output here, and assuming that the jumping motion is started, the period until the next time t2 is: During the slow-up period of the approach to increase the jump ascending movement speed to the predetermined set value, the position P1 rises to the position P2, from which a speed command signal for performing the ascending movement Vu at the set jumping movement speed V0. Is output during the period t2 to t3, and the predetermined jump amount Lj
To reach the position P3 (Lp), and control the deceleration and stop until time t4 to reach the highest ascending position P4, where the ascent stops. Then, the descent movement V of the jump movement speed V0 set during the time t5 from this time t4 or the immediately preceding time position.
d, a signal of a speed command for performing the operation t is supplied, and the time t
5, descends to the position P5, from here until time t6, or t
Until an appropriate time position up to 6, the process proceeds to the slowdown period of descending deceleration, and until it descends to the position P6 (Lm),
The jumping motion is ended, the process shifts to the proximity processing period by the servo control feed, and the processing is continued until the start determination signal of the next jumping motion is output from the determination unit 20.

Here, the time and speed characteristics during the ascending acceleration period from the position P1 to P2 from time t1 to t2 and the descending and decelerating period from position P5 to P6 from time t5 to t6 are different depending on the machining gap. The deceleration and the gradual increase / deceleration are set in order to prevent the adverse effects of the negative pressure and the positive pressure that are generated, but the former is calculated by fuzzy inference, which will be described later. It is preferable that the logic selection is set by the moving speed Vu and the jump amount Lj of the moving object, and also by the moving speed Vd of the jump descent and the descending amount (≒ Lj). A slow-up / slow-down control system or the like according to the ascending / descending moving speeds Vu and Vd may be used. In addition, the respective moving speeds of the ascent and descent may be set to the same value Vu = Vd, but from the viewpoint of increasing the effect of discharging the machining chips from the machining gap, the latter is set to be larger Vu <Vd. Alternatively, the former is set smaller and Vu <Vd may be set smaller with an emphasis on prevention of the operation of generating a large load at the time of lifting and separating the electrodes. If the slowdown control is introduced at the end of the rise at the speed Vu, there is no overshoot to the position P4, and the vehicle falls from the right position P3 to the position P5 at time t5−t4 = 0 at the speed Vd. It becomes a characteristic diagram.

Next, two conditions of the jump motion in the present invention, the jump amount (L) and the jump moving speed (V)
Fuzzy inference from the former with the respective membership functions of machining area (S) and machining depth (D), and the latter with the respective membership functions of machining area (S) and machining gap length (G). An example of a method for obtaining the above will be described. Note that the fuzzy inference example below shows a case where each set of membership functions in each set is divided into three large, medium, and small sets in order to avoid complication of the inference results. Of course is not limited to this. A, B, and C in FIG. 3 represent a machining area (S) and a machining depth (S) as each membership function for inferring the jump amount (Lj) and the moving speed (normally V0 ≒ Vu = Vd). FIG. 9 shows the membership of the above-described large, medium, and small sets as a whole with respect to the values of each example of D) and the machining gap length (G). 4A and 4B are the machining area (S) and machining depth (D) of the membership function.
And a fuzzy inference rule B for inferring a jump moving speed (V0) from a machining area (S) and a machining gap length (G). Fuzzy inference rules can be expressed as the following logical tables, respectively. In the above rule tables of A and B, S, D, and G represent a processing area, a processing depth, and a processing gap length, respectively.
And G by small letters suffixes L, M, and S to mean large, medium, and small, respectively.
L and V denote the jump amount and the moving speed, respectively, and fast, medium and slow, respectively, by the small letter suffixes H, M and S attached to L and V, respectively. Things.

The following logic table is an example of an inference rule for the jump amount (Lj). (Rule A) If the machining area is small and the machining depth is large, the jump amount is large. If the machining area is small and the machining depth is medium, the jump amount is large. If the machining area is small and the machining depth is small, the jump amount is medium.If the machining area is medium and the machining depth is large, the jump amount is large. If the machining depth is medium, the jump amount is medium.If the machining area is medium and the machining depth is small, the jump amount is small.If the machining area is large and the machining depth is large. If the machining area is large and the machining depth is medium, the jump amount is medium.If the machining area is large and the machining depth is small, the jump amount is medium. ,small

The following logical table is an example of an inference rule of the jump moving speed (V0). (Rule B) If the processing area is small and the processing depth is large, the jump speed is high. If the processing area is small and the processing depth is medium, the jump speed is high. If the machining area is small and the machining depth is small, the jump speed is fast.If the machining area is medium and the machining depth is large, the jump speed is fast.If the machining area is medium, If the processing depth is medium, the jump speed is normal.If the processing area is medium and the processing depth is low, the jump speed is normal.If the processing area is large and the processing depth is high. If the machining area is large and the machining depth is medium, the jump speed is slow.If the machining area is large and the machining depth is small, the jump speed is ,slow

FIGS. 5A and 5B show large, medium, small, and fast values of the jump amount and the jump moving speed in each embodiment.
Usually, the membership of each of the slow sets is shown as a whole.

In the present invention, the output frequency of the discrimination signal of the machining gap by the machining state detection and discrimination device 12 with respect to a predetermined machining time or the like, the output frequency or the number of times with respect to a predetermined number of voltage pulses or discharge pulses, or the like. Exceeds the predetermined level, based on the setting judgment condition of the jump start judging means 20 of the jumping motion control unit 18, the judging means 20
Outputs an inference command signal to the fuzzy inference unit 19 to infer the jump amount and the jump moving speed, and sets the jump amount (Lj) and the jump moving speed (V0) obtained by the inference. , To instruct and execute the start of the jumping motion under the conditions set by the inference.
More preferably, the present invention repeatedly outputs the machining state detection / determination device 12 so that the judgment by the jump start determination means 20 is performed more accurately and surely in a state matching the machining gap state. In response to the detection determination signal, the voltage pulse supply control means 11 sequentially increases the voltage pulse supply conditions supplied from the processing voltage pulse supply power supply 10, particularly the pause between voltage pulses, according to the deterioration of the processing state. Conversely, the control of the supply control means 11 is configured to perform control to sequentially decrease to a set value in accordance with the normalization of the processing state, and the method of increasing the idle time is determined by the electrode / workpiece. Depending on the material, combination, type of processing, dimensions and shape, purpose of processing, etc., a plurality of types are prepared, for example, τoffA and B in FIG. In the control change pattern of ff, for example, in the case of τoffA, the pause time control is prepared so as to correspond to the continuous output frequency 6 of the deterioration determination signal, and in the case of τoffB, to correspond to the continuous output frequency 7. The highest control signal is supplied from the supply control means 11 to the voltage pulse power supply 1
When the control signal is output to 0, the jump start determination unit 20 receives this control signal, immediately outputs an inference command signal to the fuzzy inference unit 19, and instructs the start of the jump motion under the conditions set as described above. , To run. In the above-described control change pattern of the pause time, for example, when the number of continuous outputs of the deterioration determination signal of τoffA is 5, the number of times is 4, and when the pause time control reaches the highest control level, the next determination signal Is in the waiting state (whether the machining gap condition has improved or is still bad), the execution of the inference is performed at the stage when the number of times 4 is reached. It is desirable to select a time when it is determined that

As described above, the jump start determining unit 2
When the inference command is input from 0 to the fuzzy inference unit 19, the jump amount inference unit 19A infers the jump amount (Lj) from the machining area data of the electrode or the like currently being machined and the machining depth data currently being machined, Jump movement speed inference unit 1
9B infers a jump moving speed (V0) from the machining area data and the machining gap length data, outputs the jump movement speed (V0) to the jump drive control means 13 together with a jump start command signal, and executes the jump motion under the inferred set conditions at the above time. Start and let it run. Thus, the processing area data of the electrode or the like currently being processed as described above is most simply obtained by the input device 1 before starting the processing.
From the Z-axis direction projected area data of the electrode obtained from the electrode / workpiece shape and dimension data and the like input to the controller 14 from 6 or from the input shape and dimension data and From the current machining position or the current machining feed position data obtained from the position detection device 7 or by integrating the machining removal amount per discharge pulse according to the set machining conditions by the number of generated discharge pulses per predetermined machining time. The processing area data obtained by dividing the processed amount by the processing feed size per the predetermined processing time may be used. The machining depth data may be, for example, a machining start position obtained from the various input and setting conditions and data by the control device 14 in an NC manner, or an electrode / workpiece provided at the start of machining by feeding the electrode / workpiece in close proximity. The position at which the discharge occurs or a position having a predetermined relationship with the position is defined as the machining start position, and can be obtained from the current machining feed length position data obtained from the position detection device 7 based on the machining start position. The data of the machining gap length is most simply obtained by the control device 14 receiving the input and setting of the target machining performance and machining information and the like determined by the machining conditions and the like, such as logical operation and selection setting. The average machining gap length is used as data, or the machining start position data is obtained at the same time, or the gap data obtained by short-circuiting with the machining start position or the position during machining, and the closest depth at the time of measuring the desired machining gap length. The machining gap length data currently being machined can be obtained from the relationship between the machining feed position data and the like.

Then, the necessary jump amount (L
By performing the inference of j) by combining the machining area during machining or the like and the machining depth data of the machining hole, the inferior machining scrap at the current machining position is generated according to the amount of accumulated machining debris currently being machined. It is possible to infer and set the jump amount (Lj) of the electrode separation suitable for the discharge and concentration control of the like, and to infer the necessary jump moving speed (V0) by combining the data of the processing area and the processing gap length. By doing so, when the machining area is large and the gap length is small on one side, the occurrence of abnormal negative pressure and positive pressure acting on the machining gap at the time of opening and approaching is prevented, and the electrode, workpiece, and electrode The movement speed of the jump motion that can eliminate the effect of mechanical force on the spindle, machining head, etc. and overload on the servo motor, while shortening the time required for the jump motion, while increasing the pump action. (V0) is preferred It is those that can be inferred setting.

As described above, during the electric discharge machining, when it is necessary to recover the machining gap state by discharging machining chips and the like from the machining gap due to the jumping motion, another jumping motion that cannot be replaced is performed. It is possible to perform a jumping motion having a jump amount and a jump moving speed condition according to the processing condition and the processing state. However, according to the method of the present invention, the processing state of the processing gap is reduced to a certain extent. Directly or indirectly, such as the control state of the controlled pause time, by a signal configured to activate the start of the jumping motion, the electrode after the jump separation performs a predetermined jump amount jump, Next, it descends at the inferred movement speed, returns to the vicinity of the machining gap position before the start of the jumping motion, and the machining voltage pulse supply power supply 10 is turned on to discharge. Then, the state shifts to the servo control feed state (the position in FIG. 2, P5 and between P5 and P6), or the voltage pulse supply power supply 10 starts the jump movement (the position P1 in FIG. 2 and the position from P1 to P2 in FIG. 2). In the meantime, when it returns to near the original machining gap position without being shut off without interruption and the discharge resumes spontaneously and shifts to the machining state, intense conditions such as flow agitation in the machining gap occur. The machining discharge state is unstable, probably because of the remaining, and the machining state detection / determination device 12 detects and determines that the machining state has deteriorated in the same manner as at the start of the start of the jumping motion.
At the time of or near immediately after the position P6, a jump motion may be started by a new inference setting. Therefore, there is a high possibility that the machining efficiency is reduced due to excessive jump motion. .

For this reason, in the present invention, when the jumping motion is started and performed according to the present invention described above, at the end of the motion, the jumping motion is moved to a position near the machining gap before the start (near the position P6 in FIG. 2). Until the electrode 1 descends and approaches, the detection discrimination signal or the supply control signal for judging the start of the jumping motion from both or one of the detection discriminating device 12 and the supply control means 11 is a jump motion start-up judging unit. 20
The jump drive control means 13 supplies a determination suppression signal to the determination unit 20 so that the determination unit 20 does not output a fuzzy inference command signal based on the determination even when the determination signal is input to the determination unit 20. . After the descent to the vicinity of the position P6, the state shifts to the machining state of the servo control, and after the judgment suppression signal from the jump drive control means 13 is canceled and disappears, the detection determination device 12 and the supply control means 1
In the case where a detection determination signal or a supply control signal for determining the start of the jumping motion is input to the determining unit 20 from both or any one of the above-described embodiments, even if it is immediately after the end of the previous jumping motion, the present invention is applied. Is naturally performed as the next jumping motion by

Further, in the present invention, at the end of the jumping movement, the electrode 1 descends to a position near the machining gap before the start (near the position P6 in FIG. 2 described above), and the machining by servo control feed is performed. Until the transition, the restarting of the jump motion as described above is not started, so that the detection discrimination signal from the processing state detection discrimination device 12 is not input to at least the discrimination unit 20, or the supply control is further performed. Means 1
The supply control means 11 which has not returned to the condition of the voltage pulse supply control of the set processing condition due to the jump motion being performed even if it is not input to 1 or the input to the means 11 is not input to the determination unit 20. Is desirable. Then, it is determined whether or not the electrode once descends and approaches the position near the machining gap (near the position P6 in FIG. 2) before the end of the end of the jumping motion and the process shifts to machining by servo control. It is preferable to adopt a different method as described below depending on the formation and supply form of the rectangular wave voltage pulse by switching on / off the voltage pulse supply power supply 10 for use.

One of them is that the power supply of the machining voltage pulse supplies a rectangular-wave-shaped voltage pulse with a pause, and a voltage pulse application time signal by turning on a switch element is supplied to the discharge gap. The voltage pulse is increased as a function of the discharge start delay period from the start of application of the pulse to the start of discharge in the discharge gap, that is, the voltage pulse is set so that the discharge duration of each discharge pulse always becomes a constant value for each discharge. A so-called on-clamp voltage pulse generation and supply system in which the measurement of the discharge duration signal is started from the start of the discharge in the discharge gap after the start of application of the voltage, and the switch element is turned off when the measurement is completed to shift to a pause time due to the end of the discharge. In the case of (for example, see Japanese Patent Publication No. 44-13,195), for example, the lowering position of the electrode 1 is changed from the position near P5 to the discharge of the machining gap. The repetition frequency is repeatedly detected, and while the detected discharge repetition frequency is increasing each time it is detected, it is determined that the machining gap is being adjusted and controlled to return to the normal machining gap state. The configuration is such that the detection determination signal is not supplied from the detection determination device 12 to the voltage pulse supply control means 11 and the jump start determination unit 20.

The other is that a constant ON duration signal and OFF pause time signal of a preset machining condition are set except for a case where the switch element is changed and controlled based on discharge state detection information of a machining gap. In the case of a voltage pulse generation and supply system using a free-running pulsar signal that supplies a voltage pulse repeatedly and regularly (for example, see Japanese Patent Publication No. 41-9,399), for example, the electrode 1 The average machining voltage of the machining gap is repeatedly detected from the position near P5 at the descent position of P5, and the detected average machining voltage is the reference voltage for servo control feed for machining or the absence of machining voltage pulse. 1 / of load voltage
When the voltage is equal to or higher than 2, the machining gap is determined to be being adjusted and controlled to return to the normal machining gap state, and the detection discrimination signal from the machining state detection discrimination device 12 is jumped to the voltage pulse supply control means 11. The configuration is such that it is not supplied to the activation determination unit 20.

[0032]

According to the first aspect of the present invention, a jump motion different from servo control feed for maintaining a machining gap in drilling using a bar-shaped or full-form electrode or the like, or in a die-sinking electric discharge machining, is performed. Regardless of various strokes and cycle settings in advance, it is activated only when it is determined that it is really necessary from the detection of the machining state of the machining gap, and the separation distance of the jump motion is set to the current machining position. From the machining area including the machining area of the electrode and the machining conditions including the data of the depth of the machining hole, and the movement speed including the relative movement speed characteristic of the separation and proximity of the jumping motion, the movement speed of the electrode at the current machining position is determined. From the machining conditions including the machining area and machining gap length data, the jump motion is fuzzy inferred based on the signal determined to be necessary, and the jump motion is made practical with the automatically set data. When is needed, and since to be performed by quantitative conditions requiring at that time, it is possible to improve the machining speed and the machining performance of the electrical discharge machining, such as 斯種 engraving.

According to the second aspect of the present invention, a jumping motion different from the servo control feed for maintaining a machining gap in drilling using a bar-shaped or full-form electrode or the like, or in a die-sinking electric discharge machining is performed in advance. Regardless of the setting of various strokes and cycles, the processing voltage is detected by the processing state detection signal during processing by servo control feed so that the processing is started when it is really needed from the processing state detection of the processing gap. The pause time between pulses is sequentially controlled to increase at a preset magnification in accordance with the deterioration of the processing state, and conversely, is gradually reduced to a predetermined value in accordance with normalization. When the pause time increases to a predetermined magnification value due to deterioration of the state or the like, the command signal generated initiates the start of the jump movement opening operation, and the command signal generates the jump movement separation executed. distance The former is based on the processing conditions including the data of the electrode processing area and the depth of the processing hole at the current processing position, and the latter is based on the processing area and processing of the electrode at the current processing position. Since it is automatically set by inferring by fuzzy inference from the processing conditions including the gap length data, it is possible to more accurately judge when the jumping motion is necessary and to perform the jumping motion more accurately and execute it. Since the conditions of the amount and speed of the jump motion to be performed conform to the required conditions, the machining speed and machining performance of the electric discharge machining such as this type of engraving can be further improved.

According to each of the first and second aspects of the present invention, the jumping motion under the required and satisfactory conditions should have been performed when necessary during the electric discharge machining. Upon completion, the operation is returned to the vicinity of the machining gap position before the start of the jumping motion, and is then shifted to a normal machining state by gentle downward feed so that the operation command signal of the jumping motion is not output when the machining is resumed. According to the third aspect of the present invention, the processing voltage pulse supply power supply switches the ON time signal of the switch element that generates the rectangular wave voltage pulse from the start of the application of the voltage pulse to the discharge gap. Increases as a function of the discharge start delay period until discharge starts in the discharge gap,
That is, after the start of the application of the voltage pulse so that the discharge duration of each discharge pulse always becomes a constant value for each discharge, measurement of the discharge duration signal is started from the start of discharge in the discharge gap, and upon completion of the measurement, It is intended to better achieve the purpose when applied to the so-called on-clamp type voltage pulse generation method in which the switch element and the off state are shifted to the idle time,
According to the fourth aspect of the invention, the machining voltage pulse supply power supply controls a switch element for generating a rectangular wave voltage pulse by a predetermined constant except for a case of changing and controlling the switch element based on discharge state detection information of a discharge gap. It can be applied to the case of the voltage pulse generation and supply system using the pulse signal of the free-running oscillation which supplies the voltage pulse in which the ON duration signal and the OFF pause time signal are alternately and regularly repeated. is there.

According to the fifth aspect of the present invention, the apparatus for implementing the electric discharge machining method according to the third aspect of the present invention is configured to have a high degree of perfection, and the objects and effects of the invention can be further improved. It is possible to provide an electric discharge machining control device that can be reliably achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an apparatus in which an electric discharge machining control method according to the present invention is implemented.

FIG. 2 is a graph of an embodiment for explaining an operation of a jumping motion in the present invention.

FIGS. 3A, 3B and 3C are membership functions for inferring a jump amount and a moving speed A: machining area (S), B:
The figure which shows the relationship between the set of machining depth (D) and C: machining gap length (G), and membership.

FIGS. 4A and 4B are fuzzy inference rules for inferring a jump amount (L) and a jump moving speed (V).

FIGS. 5A and 5B are diagrams showing a relationship between a set and a membership for each example value of a jump amount (L) and a jump moving speed (V).

FIG. 6 is a table showing two examples of an increase characteristic by controlling a pause time (τoff) between voltage pulses.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Processing electrode 2 Workpiece 3 xy cross table 3x, 3y Each axis drive servomotor 4 Processing tank 5 Processing liquid 6 Z-axis feed servomotor 7 Feed position detection device 8 Rotation speed detection device 9 Drive device 10 Processing voltage pulse supply Power supply 11 Voltage pulse supply control means 12 Machining state detection and determination device 13 Machining servo control sending means and jump drive control means 14 Control device 15 Display device 16 Input device 17 External storage device 18 Jump motion control unit 19 Fuzzy inference unit 19A Jump amount Inference unit 19B Jump movement speed inference unit 20 Jump activation judgment unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisanori Yamada 3-12-1 Nakamachidai, Tsuzuki-ku, Yokohama-shi, Kanagawa Prefecture Inside the Sodick Corporation Headquarters / Technical Training Center (72) Inventor Kuniharu Yamada Sakai-machi Nagaya, Sakai-gun, Fukui Prefecture 78 Sodick Fukui Office

Claims (5)

[Claims] 1. A machining fluid is interposed in a minute machining gap formed between a machining electrode and a workpiece to face each other, and is applied intermittently with a pause while maintaining the machining gap by servo control feed. The electric discharge machining is performed by electric discharge generated by the applied voltage pulse, and is different from the servo control feed for maintaining the gap to the electrode or the workpiece during the machining, the original after the machining gap is separated. In the electric discharge machining control method in which machining is performed while performing a jumping motion approaching to the vicinity of the gap position when an operation command signal is input, the separation distance which is a setting condition of the jumping motion is at least at the current machining position. Based on the machining conditions including the data of the machining area of the electrode and the depth of the machining hole, the moving speed including the relative moving speed characteristic of the separation and proximity, which is another setting condition of the jumping motion, is at least small. It is also possible to automatically set the processing conditions of the electrode at the current processing position and the processing conditions including the data of the processing gap length by fuzzy inference, respectively. When the operation command signal of the jumping motion is output by the detection discrimination of the period of application, the value of each setting condition of the jumping motion is calculated based on each data value at the current machining position at the time of the detection discrimination. The above-described electric discharge machining control method, wherein the automatic setting is performed and the opening operation of the jumping motion under the set conditions is started. 2. A machining liquid is interposed in a machining gap formed between a machining electrode and a workpiece to face each other, and is applied intermittently with a pause while maintaining the machining gap by servo control feed. This is electric discharge machining in which machining is performed by electric discharge generated by a voltage pulse, and the electrode or the workpiece is separated from the servo control feed during machining to a position near the original gap position after the machining gap is separated. The machining is performed while the adjacent jumping motion is performed when the operation command signal is input, and the pause between the voltage pulses is sequentially reduced according to the deterioration of the machining state by the machining state detection signal during the machining by the servo control feed. In the electric discharge machining control method in which machining is performed while performing a pause time control so as to increase and control and gradually decrease to a set value according to normalization, the separation distance which is a setting condition of the jump motion Is the movement including at least the processing area of the electrode at the current processing position and the processing condition including the depth data of the processing hole, and the movement including the relative movement speed characteristic of the separation and proximity which is another setting condition of the jump movement. The speed can be automatically set at least by fuzzy inference based on at least the processing area of the electrode at the current processing position and the processing conditions including the data of the processing gap length. As a signal indicating that the increase control level has been reached, the values of the respective setting conditions of the jump motion are automatically calculated based on the respective data values at the current machining position during the pause time control, and the set values are set. The above-mentioned electric discharge machining control method, characterized in that an opening operation of a jump motion under a condition is started. 3. The discharge repetition frequency of the machining gap is repeatedly detected from a position immediately before the machining gap, which is the end of the started jumping motion, returns to the position at the start of the jump. The method according to claim 1 or 2, wherein the detection of the machining state of the machining gap for generating and outputting the operation command signal of the jumping motion is suppressed while the number of the machining gaps is increasing.
3. The electric discharge machining control method according to claim 1. 4. An average machining voltage of the machining gap is repeatedly detected from a position immediately before the machining gap, which is the end of the started jumping motion, returns to a position at the start of the jump. However, while the reference voltage for the servo control feed for the machining or the voltage equal to or more than 電 圧 of the non-negative voltage of the machining voltage pulse, the machining state of the machining gap for generating and outputting the operation command signal of the jump movement is provided. The electric discharge machining control method according to claim 1 or 2, wherein the detection and determination of (i) are suppressed. 5. A machining liquid is interposed in a minute machining gap formed between a machining electrode and a workpiece to face each other, and is applied intermittently with a pause while maintaining the machining gap by servo control feed. In the electric discharge machining control device for machining by electric discharge generated by the applied voltage pulse, the original gap after the opening of the machining gap is separated from the servo control feed to the electrode or the workpiece during machining. A jump drive control means for performing a jumping motion to approach the position close to the position when an operation command signal is input and a machining state detection signal during machining by servo control feed, the pause time between voltage pulses according to the deterioration of the machining state. A voltage pulse supply control means of the voltage pulse supply power supply for controlling the voltage pulse supply power supply to sequentially increase the voltage to a set value in accordance with the normalization; A jump motion control unit having a logic unit and a jump motion activation determining unit; and a fuzzy inference unit for the jump motion condition, wherein a depth data of a processed hole based on a current feed position detection signal of the electrode and input processing condition data or processing. A jump amount estimating unit for inferring a separation distance of a jump motion from current electrode machining area data obtained by detecting from a progress state and outputting a jump amount signal to the jump drive control means; A jump for outputting a jump moving speed signal including a relative moving speed characteristic of a jumping motion to the jump drive control means from machining condition data or data of a machining gap length obtained from current and past feed position detection data of the electrode. The jump amount and the jump amount are determined based on a judgment signal from a moving speed estimating unit and at least a start judging unit of the jump motion. Fuzzy inference unit control means for executing inference in each inference unit of the jump movement speed and outputting a signal and outputting a jump movement start command signal to jump drive control means; The determination unit determines the inference command when the output state of the control signal of the pause time control output to the voltage pulse supply power by the voltage pulse supply control unit exceeds a predetermined level of the pause time control pattern set as input. The above-mentioned electric discharge machining control device, which outputs a signal.