JP3330779B2 - Positioning method and apparatus for wire electric discharge machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for positioning a wire electric discharge machine.

[0002]

2. Description of the Related Art Generally, a wire electrode stretched in a substantially vertical direction is renewed and a discharge phenomenon is generated between the wire electrode and a workpiece, so that the wire electrode has a desired shape. As a device that performs processing with a contour shape at the place,
Wire electric discharge machines are known. This type of wire electric discharge machine has extremely high machining accuracy and is suitable for precision machining. When performing machining, in order to perform machining at a predetermined location on the workpiece with high precision, the wire electrode is brought into contact with the reference surface or reference hole of the workpiece, which is a reference for the machining position, and the contact position is determined. The contact position
Each position on the workpiece is relatively determined as a reference position of the electric discharge machining . Therefore, seeking the reference position before machining
Positioning for positioning the wire electrode with respect to the workpiece has a great effect on processing accuracy and is a very important operation.

Here, a method for positioning a conventional wire electric discharge machine will be described with reference to FIG. As shown in the figure, the workpiece W is fixed to a work stand 4 provided on the XY table 2, and a wire supply / transporting means 8 for moving the wire electrode 6 toward the workpiece W.
Is arranged so that the wire electrode 6 wound around the wire bobbin 9 is sandwiched between the most downstream recovery roller 10 and the pinch roller 12 and is pulled out with a constant force, and is sent out. The tension applying mechanism 22 including the powder brake 18 and the pinch roller 20 and the pulleys 21 and 23 are interposed. In addition, wire electrodes 6 are arranged above and below the workpiece W so as to sandwich it.
An upper guide 24 and a lower guide 26 for guiding the traveling direction of the vehicle are arranged.

[0004] Further, above the upper guide 24, a power supply 2 for contacting the wire electrode 6 and supplying power thereto.
A machining voltage supply unit 30 for supplying a pulse-like machining voltage between the power supply 28 and the work stand 4 and a contact detection unit 3 used when determining the center position.
2 are connected. An NC device 33 composed of a microcomputer or the like controls these operations, and controls a drive motor 36 via a driver 38 based on coordinate information from an encoder 34 provided in the XY table 2. Thus, the relative position between the wire electrode 6 and the workpiece W is controlled. Although the upper guide 24 or the lower guide 26 is actually moved to control the relative position, it is omitted in the illustrated example for the sake of simplicity. In such a configuration, the position where the wire electrode 6 and the workpiece W first make contact with each other is detected by the contact detection unit 32, and the coordinates of each unit are determined using this as a reference position or reference coordinates. .

The tension of the wire electrode is given by a tension applying mechanism 22 provided between the wire supply side and the wire electrode take-up side. Guide 2
It is inevitable that a slight vibration occurs between 4, 26. Causes of this vibration include elongation of the wire electrode due to the application of tension, frictional resistance between the power supply 28 and the wire,
Although the vibration is generated due to the fluctuation of the tension due to the tension control, the vibration cannot be set to the non-vibration state even if the vibration is designed to be as small as possible. The vibration frequency of the wire is a state in which a plurality of frequencies are mixed, but about 1 KHz to 2 KH.
Vibration of about z greatly affects positioning accuracy.

Therefore, in consideration of such vibration of the wire electrode, as an example, the following various positioning methods have been proposed. In JP-A-63-93524,
Using a jig having upper and lower contact detection electrodes, the upper and lower groove widths to be detected are provided symmetrically, and the contact detection position where the travel of the wire electrode is stopped there, and the wire electrode is moved. The vibration width is determined from the difference between the contact detection position in a state where the wire electrode is running and the contact detection position in a state where the wire electrode is running, and true vertical coordinates are obtained. Also, Japanese Patent Application Laid-Open No. 2-1
According to Japanese Patent No. 60423, if the positioning is performed while the wire electrode is running, the running causes micro-vibration in the wire electrode, which lowers the accuracy and reproducibility. Therefore, the running of the wire electrode is stopped and a predetermined tension is applied. There has been proposed a configuration in which positioning is performed while being given.

Further, in Japanese Patent Application Laid-Open No. Hei 1-306132, the wire electrode and a vertical jig having two detection points at the top and bottom are used to vertically set the wire electrode. The number of times the wire electrode contacts the detection point is counted, for example, only the upper portion, only the lower portion, both the upper and lower portions, and no upper and lower contacts, and the upper wire guide is driven forward or backward by each count. This discloses a configuration in which the wire electrode is vertically corrected.

[0008]

However, each of the above-mentioned conventional devices has the following problems. First,
In the technique disclosed in Japanese Patent Application Laid-Open No. 63-93524, the wires are brought into contact in a running state and a stopped state, and the difference is regarded as the vibration width of the wire electrode to correct the difference. However, when the wire electrode is stopped and positioned, the position where the wire electrode is stopped does not always stop at the same position but stops at some point in the vibration width, so that the stop position is not stable. The reason is that there is a difference between the hole diameter of the guide and the diameter of the wire electrode, and that the wire electrode is always drawn by the wire feeder because the wire feeds over the wire electrode axis. It is in. In addition, there are many cases where it is caused by attached matter such as dust. Therefore, it is not possible to determine at which position of the vibration width the position of the wire electrode in contact with the workpiece is in contact. That is, when the wire electrode is not vibrating, the wire electrode and the workpiece are relatively moved and positioned by a servo to a position where it should be, but it is unknown at which vibration position of the vibrating wire electrode the contact was made. is there.

Further, since the processing is performed under a predetermined wire electrode feed speed and a predetermined tension, the position cannot be determined as a true center position during the processing unless a position is detected in a running state during the processing. In addition, the second Japanese Patent Application Laid-Open No. 2-160
In Japanese Patent No. 423, the wire electrode is stopped and positioned without vibration. However, in this case, as described in the first publication, at which position in the vibration width the wire electrode stops. Since the stop position is not known, the stop position is not stable, and has the same problems as in the first publication. Further, in Japanese Patent Application Laid-Open No. Hei 1-306132, the vertical positioning operation is performed with the wire electrode stopped, and in this case, the same problem as described above occurs.

The present invention has been made to solve the above problems. An object of the present invention is to eliminate a detection error due to vibration of a wire electrode by detecting a contact position of the wire electrode while running the wire electrode while placing the wire electrode in the same environment as during processing during contact positioning. It is an object of the present invention to provide a method and a device for positioning a wire electric discharge machine.

[0011]

[MEANS FOR SOLVING THE PROBLEMS] To solve the above problems.
Of the positioning method of the wire electric discharge machine of the present invention
Process, a pair of wire guides (24), (26) Te stretched wire electrode (6) and the positioning method smell of the workpiece (W) to perform electric discharge machining relative movement wire electric discharge machine between a step for running word ear electrodes (6) under a predetermined tension, the workpiece a ring ear electrodes (6)
A step of relatively moving to approach the (W), Wa ear electrodes (6) and the workpiece (W) and applying a detection voltage workpiece and the wire electrode (6) during the (W Between)
Detecting the voltage of the power supply, and based on the detected voltage.
The wire electrode (6) is located at the tip of the workpiece (W).
And stay at the center position (B) of the vibration width of the wire electrode (6)
So that the wire electrode (6) is in phase with the workpiece (W).
Counter-advancing or retracting, wire electrode
(6) forward or backward relative to the workpiece (W)
While retracting, the wire electrode (6) and the workpiece (W)
Repeatedly detecting the relative position of the
Center of the oscillation width of the wire electrode based on the relative position
Find the position, determine it as the reference position for EDM, and
Step for positioning the pole (6) with respect to the workpiece (W)
And Also, the wire discharge of the present invention
The basic configuration of the processing machine positioning device consists of a pair of wires
Wire electrode stretched between guides (24) and (26)
(6) a wire supply / transfer means (8) for traveling,
Tension applying machine for applying a predetermined tension to the wire electrode (6)
Structure (22), wire electrode (6) and workpiece (W)
Movement mechanism for relative movement, wire electrode (6) and work
Processing voltage supply unit (3) for supplying a voltage between the workpiece (W)
0) and the voltage between the wire electrode (6) and the workpiece (W).
And a contact detection unit (32) for detecting pressure.
In the positioning device of the electric working machine, the contact detection unit (32)
Wire electrode (6) is processed based on the voltage detected in
At the tip of the object (W), within the vibration width of the wire electrode (6)
Wire electrode (6) is applied so as to stay at the center position (B)
Move forward or backward relative to the workpiece (W)
Moving mechanism control section (41) for driving and controlling the moving mechanism
And a voltage based on the voltage detected by the contact detection unit (32).
Substantially Wai ear electrodes (6) is to the tip of the workpiece (W)
In the state of being located at the center position of the vibration width of the
When the wire electrode (6) comes into contact with the workpiece (W)
The relative position of the detected wire electrode (6) and the workpiece (W)
A coordinate storage unit (70) for sequentially storing coordinate values of the coordinates,
Coordinates of the plurality of relative positions stored in the storage unit (70)
Calculate the average value and determine it as the reference position for EDM
And a contact position calculation processing section (76).

[0012]

With the above arrangement, at the time of positioning, the wire electrode and the workpiece are relatively moved while the wire electrode is running under a predetermined tension. At the time of the relative movement, the movement of the wire electrode and the workpiece is controlled by a servo that repeatedly performs a contact operation and a separation operation. Then, the position coordinates at the time of contact / separation are stored, and if a predetermined number of position coordinates are detected, a calculation for averaging the variation of the movement control to the center position at the indefinite amplitude is performed, It is possible to more accurately determine the reference position of the electric discharge machining . In this case, if the relative movement amount deviates from the permissible range during the contact / separation operation, it is determined that an error has occurred, and the initial coordinates serving as the tentative reference position for setting the permissible range are reset and re-executed. This makes it possible to place the wire electrode under the same environment as during processing and determine the contact position while running the wire electrode.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a wire electric discharge machine according to an embodiment of the present invention; FIG. 1 is a schematic configuration diagram showing a positioning device of the wire electric discharge machine according to the present invention, and FIG. 2 is a block configuration diagram showing a control unit of the positioning device shown in FIG.
The same parts as those shown in FIG. 9 will be described with the same reference numerals.

As shown, this wire electric discharge machine is
It has an XY table 2 installed on a base 40,
The workpiece W is fixed thereon via the work stand 4. The XY table 2 has a ball screw 35 for moving the table and a drive motor 36 such as a step motor for rotating the table screw.
It can be moved to any position in the direction. The position (coordinates) of the workpiece W is determined by an encoder 34 provided in each drive motor 36 (only one is shown in the figure).
Is detected by In the illustrated moving mechanism, XY
Although only the table 2 can be moved, in practice, the upper guide 24 or the lower guide 26 can also be moved, and their positions are controlled by their relative movement. Therefore, the guide moving mechanism is omitted.

On the other hand, facing the workpiece W, a wire electrode
The wire supply / transporting means 8 for traveling the wire 6 is configured to feed the wire electrode 6 wound around the wire bobbin 9 by sandwiching the wire electrode 6 between the most downstream recovery roller 10 and the pinch roller 12 and pulling the wire electrode 6 with a constant force. cage, middle and pulley 14, pulley 16, is interposed a tension application mechanism 22 and pulley 21, 23 made of powder brakes 18 and the pinch roller 20. An upper guide 24 and a lower guide 26 for guiding the traveling direction of the wire electrode 6 are arranged above and below the workpiece W so as to sandwich the workpiece W. Further, above the upper guide 24, a power supply 28 for contacting the wire electrode 6 so as to be able to supply power thereto is arranged, and a pulse-like processing is provided between the power supply 28 and the work stand. Processing voltage supply unit 3 for supplying voltage
Positioning device 4 used to determine 0 and center position
2 is connected to a power supply line from the contact detection unit 32 constituting a part of the power supply line 2.

An NC device 33 composed of a microcomputer or the like controls these operations.
A drive motor 36 is controlled via a driver 38 based on coordinate information from an encoder 34 provided on the XY table 2 to control a relative position between the wire electrode 6 and the workpiece.
Further, the NC device 33 has a built-in moving mechanism control unit 41 which forms a part of the present invention. This moving mechanism control unit 41
A contact state counting section 44 for receiving a signal from the contact detection section 32 and counting the time of the contact state between the wire electrode 6 and the workpiece W, and a non-contact state counting section 46 for counting the time of the non-contact state. And a movement control unit 48 that outputs a forward pulse or a backward pulse each time the respective count value reaches a predetermined time, and outputs a forward pulse when both do not contact, and outputs a forward pulse when both do not contact. A backward pulse is output so that the two are not attached and are controlled so as to maintain the relationship.

The control system described above is a control system for a mechanical unit. Next, the configuration of the arithmetic unit 50 which is a feature of the present invention for obtaining a contact position will be described with reference to FIG. FIG. 2 is a block diagram showing the arithmetic unit 50. The outline of this calculation will be described. First, when the wire electrode and the workpiece approach and come into contact with each other for the first time, their coordinate values are stored, and thereafter, a predetermined number of continuously input coordinate values are stored. . During this time, the relative movement control is performed without leaving the wire electrode and the workpiece as described above, and if a predetermined number of coordinate values are stored, the average value is obtained, Is determined. However, a plurality of check steps are provided in order to obtain a predetermined number of coordinate values because various error elements may enter. For example, the first and second initial coordinates are provided as temporary reference coordinates, and when the coordinate values deviate outside of a predetermined allowable range around these coordinate values, or in the middle of an operation that does not separate without moving, An error occurs when a predetermined number of continuous movement pulses are generated in the reverse direction, and the like. In this case, the coordinate value detection operation is performed again.

First, in the figure, a first initial coordinate storage unit 52
Is a memory for storing a coordinate value when a contact signal comes from the first contact between the wire electrode and the workpiece, and the maximum allowable range is determined based on the first initial coordinates stored here. As will be described later, the coordinate values are not updated even if an error occurs, and are fixed values. The second initial coordinate storage unit 54 is a memory for storing a second initial coordinate serving as a reference. This coordinate value is different from the first initial coordinate, and is different from the first initial coordinate every time an error signal is input. Is updated to the new coordinate value.

The wide allowable range storage unit 56 is a memory for storing the maximum allowable range of the current coordinate values centered on the first initial coordinates. In the present embodiment, the memory stores the wide allowable range. In this embodiment, the wide allowable range is set to, for example, a range of ± 9 μm. The narrow area allowable range storage unit 58 is a memory that stores an allowable range that the current coordinate value can take around the second initial coordinates, and the allowable range is set narrower than the wide area allowable range. In the present embodiment, this narrow range allowable range is, for example, ± 4.
It is set in the range of μm.

The first initial coordinate comparing section 60 compares and determines whether or not the current coordinate value falls within the wide allowable range defined on the basis of the first initial coordinates. When the value deviates from the range, an error signal is output. The second initial coordinate comparing section 62 compares and determines whether or not the current coordinate value is within the narrow area allowable range determined based on the second initial coordinate. When it deviates, an error signal is output.

The continuous value counter section 64 counts the number of times when the coordinate value continuously increases or decreases by a predetermined number of times in the state where the coordinate value falls within the wide range and the narrow range allowable range. The counter unit 64 includes a continuous increase counter 64A for counting the continuous increase number and a continuous decrease counter 64B for counting the continuous decrease number. The continuous value comparing section 66 outputs an error signal when the count value of the counter section 64 reaches a predetermined value.
The comparison unit 66 includes the two counters 64A and 64B.
, A continuous increase comparator 66A and a continuous decrease comparator 66B are incorporated. In this embodiment, the set value is set to, for example, [3].

The number-of-coordinates-detection storage section 68 is a memory for storing the number of times coordinates are detected by sampling after the wire electrode first comes into contact with the workpiece. The contents of this memory are used to detect an error signal. Reset every time. The coordinate storage unit 70 is a memory for storing the detected coordinate values after the wire electrode and the workpiece have first contacted, and the contents of the memory are reset every time an error signal is detected. The reset unit 72 resets the contents of the storage units 68 and 70 each time an error signal is input from each unit.

The number-of-detections comparing section 74 compares and determines whether the value of the number-of-coordinates-detection storage section has reached a predetermined value. In the present embodiment, for example, [100] is set as the predetermined value. . When the number-of-detections comparing unit 74 determines that the number of detections has reached the set value, the contact-position calculation processing unit 76 calculates the average of the coordinate values stored in the coordinate storage unit 70 to determine the standard of the electric discharge machining. The arithmetic processing for finding the position is performed. This calculation result is displayed on a display unit 78 such as a display to notify the operator. The error count storage unit 80 is a memory that stores the error count output from each unit.

The number-of-errors comparison section 82 compares and determines whether or not the value of the number-of-errors storage section 80 has reached a predetermined value. To stop the entire operation. In this embodiment, the predetermined value is set to, for example, [5].

Next, a description will be given of a positioning method of the present invention performed by the apparatus configured as described above. After the wire electrode comes into contact with the workpiece, the apparatus simultaneously performs the vibration center movement control of the mechanical unit and the arithmetic processing of the contact position at the time of the contact so that the wire electrode and the workpiece are not attached and relatively moved. . FIG. 3 shows the flow at this time.
The above control and processing are performed in parallel by the multitask processing of the CPU. First, the processing program S
Initialization is performed by setting both T-FLG (contact flag) and END-FLG (end flag) to [0].
Then, both the vibration center movement control (S200) and the contact position calculation processing (S500) are repeatedly performed unless the END-FLG is [1]. And EN
When [1] is set in D-FLG, the determinations in S300 and S600 are NO, and the operation ends.

Next, based on FIG. 4 to FIG.
The vibration center movement control performed at 00 will be described in detail. FIG. 4 is a flowchart showing the vibration center movement control, and FIG.
Is a diagram showing the relationship between the vibration of the wire electrode and the contact detection signal,
FIG. 6 is a graph showing the relationship between the vibration of the wire electrode and the count value of each counter unit. As described above, here, when the wire electrode 6 and the workpiece W come into contact with each other for the first time, control is performed so that the wire electrode 6 and the workpiece W are not separated from each other thereafter.

First, in S201, a contact state counting section 44 (hereinafter referred to as CNT-B) shown in FIG.
K) and a non-contact state counting section 46 (hereinafter referred to as CNT).
-GO) as [0]. Also,
The F value is set to, for example, 100. Here, the F value means the feed speed of the servo motor, and determines how often the output pulse to the motor is output in one minute. In this case, if the F value is set to 100, 2 mm / m
Pulses are output at intervals such that the speed becomes in.

In S202, it is determined whether or not END-FLG is [0]. In this case, since the process for setting to [0] has not been performed, the process is executed toward [Y]. In S203, it is about to determine whether or not there is a contact signal in the contact detection unit (between the poles) 32. Here, if it is not a contact signal (NO)
In step S204, a process of counting 1 in the CNT-GO counter 46 is performed.

In step S205, the count value of the counter 46 and the set value are compared and determined by the movement control unit 48 . In this case, if, for example, 100 is input as the set value F as described above, the set value 10
The processing of S202 to S205 is repeated until the value becomes 0.
As described above, the set value 100 means the F value (feed speed) of the servo, and it is possible to set a predetermined F value by outputting the output pulse to the motor in one minute at what cycle. It is a value to determine whether it is possible. In this case, set value 1
When 00 is set, the forward servo is executed at a value of 2 mm / min. In the present embodiment, S202 to S20
The time required for one loop up to 5 is 300 μs.

In step S206, when the CNT-GO reaches 100 (Y), one forward pulse is transmitted to the motor, and the same position is maintained until this processing is executed. That is, the processes of S202 to S205 are executed until the forward pulse of the motor is output.
/ Min. Here, the movement control unit 48 sends the driver 3
One forward pulse is actually output to the motor 36 via 8. In S207, a process of clearing the CNT-GO counter 46 is performed. Here, the CNT-BK counter 44 may be cleared.

In S208, if there is a contact signal from the contact detecting section 32, that is, if YES in S203, it is determined whether or not the ST flag is [0]. S
In the case of YES at 208, the process proceeds to S209, and S209
In this example, a process for setting the ST flag to [1] is performed. This indicates that the wire electrode and the workpiece are in contact for the first time. In S210, 1 is counted in the CNT-BK counter. In step S211, the process is executed in the same manner as in step S205, but in this process, a process for retreat is performed. That is, when the count value of the counter 44 becomes the predetermined value 10
It is determined whether or not 0 has been reached.

In step S212, the same processing as in step S206 is executed, but here, the backward processing is performed. That is, when the count value reaches 100, one backward pulse is issued, the motor is moved backward, and the motor moves in a direction to separate them. In S213, the same processing as in S297 is executed,
Clear the CNT-BK counter. Here, CNT
The GO counter may also be cleared. In other words, the operations in the above series of processing will be described collectively. If the number of forward-side loops, that is, the number of times of detection of the contact state is high based on the determination of contact detection in S203,
The number of reverse output pulses to the motor increases, approaching the one to be detected for contact, and conversely, the number of reverse loops ,
That is, when the number of times of detection of the non-contact state is high, the number of reverse output pulses to the motor increases, and an operation is performed in which the number of pulses for detecting the contact is increased. By repeating such operations, the wire electrode
The relative movement of the wire electrode and the workpiece
After the wire electrode and the workpiece have once contacted each other, their relative movements are controlled so that they are not separated from each other. In other words, the number of contacts due to the vibration of the wire electrode affects the servo back or advance, and as a result,
The wire electrode vibrates at the tip of the workpiece
Operates to stay at the center of the width .

FIG. 5 shows the relationship between the vibration state of the wire electrode 6 and the state of the contact detection signal at this time. As shown
When the workpiece W gradually approaches the wire electrode 6 from the right side in the drawing, almost no load is present at the initial stage of contact, such as at point A, and the two occasionally come into contact with each other and become short-circuited. Become. Further, when the movement of the workpiece W progresses and reaches point B, for example, the no-load state and the short-circuit state become substantially the same in time. Then, when the position of the workpiece W further advances and reaches, for example, the point C, the situation is opposite to that of the point A, and the time of the short-circuit state becomes very long.

[0034] Referring now to FIG. 6 will be described change of the count value of the counter at the time of such contact. Here, the vibration frequency of the wire electrode is 2 KHz,
In the timing chart of each point when the servo operation frequency is set to 100 Hz and the contact detection frequency (sampling frequency) is set to 100 KHz, a substantially right half area is described by compressing time. Also, the set value of F is set to 1000 instead of 100, and one forward or backward pulse is output each time the count value reaches 1000. As is clear from the figure, the count values of the counter units 44 and 46 complementarily increase, and when one count value increases, the other count value stops. In the case of the point A, as described above with reference to FIG.
O counter count <br/> value (non-contact state counting section) 46 whereas increases rapidly, CNT-BK counter (contact state counting section) 46 slow increase in count values. Then, a pulse corresponding to the counter unit which has reached the set value 1000 earlier, in this case, the CNT-GO counter unit 46, that is, one forward pulse is output here.

Further, at the point B, since the contact and non-contact times between the wire electrode and the workpiece are substantially equal, the values of the counters 44 and 46 increase at substantially the same speed. That is, at this point B , as shown in FIG.
The center of oscillation width of the tip of the workpiece W is substantially the wire electrode 6
Since they are at the position, the time when both are in the contact state and the time when they are in the non-contact state are substantially the same. In other words, per unit time
Increase in the number of times the contact state is detected and the number of times the non-contact state
It becomes substantially the same amount of increase. That is, the coordinates of the point B are the contact positions (reference positions for electric discharge machining ) to be determined in advance. Further, when the position is indicated at the point C, the count state is opposite to that at the point A, and the count value of the CNT-BK rapidly increases. By performing such operation, wire Ya electrodes and the workpiece and is indecision state, that is, the wire electrode tip smell of the workpiece
The relative movement of the wire electrode 6 is controlled so that the wire electrode 6 remains at the center position B of the vibration width .

Next, a description will be given, with reference to FIG. 7, of a flow of an arithmetic processing for obtaining a contact position which is processed in parallel with the vibration center movement control as described above. First, S5
At 01, the variable values of n, E, $ B, C, and D are initialized to [0], and the storage units 68, 80, and 70 and the counters 6 are initialized.
Clear the values of 4A and 64B. Where n is the wire voltage
Pole - first a coordinate detection times after contact coordinate detection times number storage section 68 in the stored values between the workpiece, E is a number of errors of the total output, the error count storage unit 8
0 is a value stored in the coordinate storage unit 70, C is a coordinate value stored in the coordinate storage unit 70, C is a sampling number when the coordinate value continuously increases (the number of times of continuous passing through the path P1), and D is a value. Number of samples when the coordinate value continuously decreases (path P
3), and a continuous decrease counter 6
6B. S502 is ST-F
If the LG state is determined and the first contact signal is detected in the vibration center movement control (FIG. 4) described above, ST-FL is detected.
Since G = 1, this is a standby process until the first contact signal comes. When ST-FLG = 1, the process proceeds to S503, which is the next process.

In step S503, at the same time when the first contact signal between the poles is input, the coordinate value of the contact position at that time is fetched and stored in the first initial coordinate storage unit 52. still,
This value is fixed until the processing is completely completed. In S504, the same processing as in S503 is performed.
The second initial coordinate storage unit 54 stores the coordinate values at that time. This value is updated each time an error occurs. Here, the reason why the first and second initial coordinate values are provided as the initial coordinate values is that the first initial coordinate values have a certain degree of accuracy with respect to the coordinate values that are successively captured.
This is because it is necessary to provide a temporary reference line when making a determination in comparison determination processing routes S508 and S509 described later. That is, if the reference line is only the first initial coordinate value, the reference line changes every time an error occurs, and this causes a large variation in the calculation of the coordinate value, resulting in a lack of reliability. It is.

In step S505, the error circuit comparison unit 82 compares and determines the number of times of error occurrence E with a set value. Here, if an error has occurred five or more times, the operation is completely stopped. In S506, the number-of-loops detection unit 74 compares the number of loops, that is, the number n of coordinate detections, with the set value [100]. In S507, the coordinate value (n) detected between the poles
Is stored in the coordinate storage unit 70. In step S508, the coordinate values (n) successively taken in by the first initial coordinate comparison unit 60 are more limited than the tentative reference line (fixed and invariable) which is the first first initial coordinate value. A comparison is made to determine whether the distance is within ± 9 μm. This limit width is stored in the wide range allowable range storage unit 56.

In S509, the second initial coordinate comparison unit 62
In step S507, the second initial coordinate value updated only when the user enters the error route is compared with the coordinate value (n) that is successively fetched and input in step S507. This initial coordinate value is updated up to the number of errors of five. Further, the coordinate value (n) fetched in S508 is smaller than the smaller limit width ± 4 for the second initial coordinate value.
A comparison is made to determine if the distance is within μm. This limit width is stored in the narrow range allowable range storage unit 58. As described above, through the comparison determination processing in S508 and S509, first, a temporary temporary reference width of the large frame is set at the first initial coordinates.
A reference width of a frame having a smaller second initial coordinate is set in this frame. Thereby, the second initial coordinates are displaced within a range of the large frame for each error within a range of up to five errors within a range of the small frame, and are converged to obtain a good coordinate value, thereby facilitating the sieving operation. ing. That is, the coordinate values input one after another are calculated with a certain degree of accuracy so that there is no variation in the calculation.

In S510, the coordinate value comparing section 63 performs a process of comparing the coordinate value (n) with the immediately preceding coordinate value (n-1). Here, the comparison result is classified into three patterns. That is, when coordinate value (n)> coordinate value (n-1) (path P1), when coordinate value (n) = coordinate value (n-1) (path P2), coordinate value n <coordinate value (n -1) (path P3). In S512, the continuous value counter 64 counts the number of continuous times C passing through the path P1, and this value C is stored in the continuous increase counter 64A, and at the same time, the value D of the other counter 64B is cleared. S55
At 1, the number of continuous times D passing through the path P3 is counted,
This value D is stored in the continuous decrease counter 64B, and at the same time, the value C of the other counter 64A is cleared.

In S513 and S514, the continuous value comparing unit 6
In S6, a process of comparing and determining the count value in S511 and S512 with the set value [3] is performed. If any one of S513 and S514 is satisfied, an error occurs and an error signal is output. In S515, the number of loops in the number-of-coordinates detection storage unit 68, that is, the number of coordinate detections
A process for counting up the number n is performed. In S516,
The error count storage unit 80 performs a process of counting the number of errors. In S517, the reset unit 72
All variables related to arithmetic processing are cleared when the vehicle has passed the error route, and the initial state is set. Then, the process starts again from S504.

In S518, the number of loops , that is, the coordinates
When the number of detections n becomes equal to or greater than the set value [100], the average value of the coordinate values stored so far in the coordinate storage unit 70 is calculated by the contact position calculation processing unit 76, and this value is output. I do. The result is displayed on the screen of the display unit 78 such as a CRT. In S519, END-FLG =
As shown in FIG. 3, the flow of the vibration center position movement control and the contact position calculation processing ends as 1.

Here, the situation of the above-mentioned error judgment will be specifically described with reference to FIG. In the figure, black circles indicate coordinate values. a. Description of error determination 1. FIG. 8A shows S507 to S51 for a plurality of detected coordinates.
4 shows the processing status in the process between four. First, S5
03, the first and second initial coordinates are input in S504, and a temporary reference line for performing the comparison determination process is set. Then, the process proceeds from S505 to S509 properly and proceeds to S5.
When it reaches 10, it is sorted into three patterns based on the comparison judgment. Now, assuming that the loop is the first time, P2
Processing route. Then, after S513 and S514, 1 is added to the loop count in S515, and S5
It enters the processing of 06. Here, the number of loops is compared and determined, and the coordinate value is stored in the next memory. Assuming that the coordinate value is larger than the initial coordinate, a comparison determination process is performed in S510, and the process enters a processing route of P1. And S5
12 is performed, C becomes +1 and D becomes 0. The figure shows that the result of performing the processing five times has the same coordinate value in all five times. As a result of the comparison judgment, the coordinate values gradually increase from the sixth time onward. That is, C increases by +1.

In this case, the coordinate value increases three consecutive times,
Since C = 3, the process moves to the NO route in the comparison process of S513, and an error process is performed. Assuming that the direction in which the coordinate value increases is +, the wire electrode is pressed against the first contact reference position. On the other hand, in the negative direction, it is away from the reference position.

B. Explanation of error judgment 2. FIG. 8B shows the process of the comparison judgment in S508. The first point is as described above in S503 to S50.
The processing up to 7 is the same. Next, at the third time, the coordinate value (3) captured at the third time with respect to the first initial coordinates (reference coordinate line) is ± 9 μm which is the wide range allowable range.
Error, an error occurs and an error is counted. And the variables needed for the previous calculations are cleared,
The reference line of the second initial coordinates is updated to the next adopted coordinate value. Subsequent processing is performed in the same manner as described above. After the second initial coordinate value updated due to the error, the second to fifth times and the error continue, and an error stop is performed due to count over.

C. Explanation of error judgment 3. FIG. 8C illustrates the process of the comparison determination in S509. Here, a description is given of a second initial coordinate value that is within the reference width of the first initial coordinate of the large frame and further provides a narrow reference width within the width. Here, the description will be given on the premise that the comparison determination processing of S508 has been performed.
First, the first point is the same as in the above S508. Then, in the second time, the captured coordinate value (2) deviates from the reference width (narrow range allowable range) of the second initial coordinates, causing an error, and enters an error route. After one error is counted up, the variable is cleared. Then, the acquired coordinates are updated as the next new second initial coordinates. This time, the updated second initial coordinates become a new reference line, and accordingly, the narrow area allowable range also varies.

As described above, according to the present invention, the coordinates are obtained while the wire electrode is placed in the same environment as that for machining, and the wire electrode is moved so that the workpiece is not attached to the workpiece and is not separated. As a result, the detection error due to the vibration of the wire electrode is suppressed and
By relatively moving the wire electrode and the workpiece so as to stay , the reference position of the electric discharge machining can be accurately determined.

In the above embodiment, directly from S515,
Although step S506 has been entered, it is preferable to provide a delay time insertion step for performing a delay during this time. This is because, in the above-described servo flow, in order to time the process of performing the forward and backward servo drive and the process of capturing the coordinate values, for example, the time during which one feed pulse of the servomotor is output ( If the coordinate value capturing processing time is earlier than the so-called F value (which changes depending on the set value of the number of loops), the capturing of the coordinates is terminated while the motor drive pulse is not output (the motor is stopped), and the calculation is performed. The same coordinate value is taken in for 100 set values of the number of processing loops, and this is to avoid this.

By the way, the described flows, for example, in the view shown in FIG. 6, the workpiece W is relatively moved while repeatedly forward FukuUtsuri movement between point A and point C and finally discharged
Although it is guaranteed by a program to obtain the coordinates of the processing reference position (point B), if the vibration state of the wire electrode 6 is relatively regular, the wire electrode relatively moves from point A to point B. , The count values of the CNT-BK counter unit and the CNT-GO counter unit are
As shown in (2), the waveform at point A transitions smoothly to the waveform at point B. Therefore, in this case, the contact position as the final target is obtained without the wire electrode relatively moving to the point C side.

The increment of the count value of the CNT-BK counter for counting the time of the contact state between the wire electrode and the workpiece, and the count of the CNT-GO count section for counting the time of the non-contact state between the two. When the increments of the values are substantially the same, in other words, as shown by the waveform at the point B in FIG. 6, the coordinate position when the increments of the two count portions are substantially the same is determined as the contact position. A program may be incorporated. With this configuration, as described above, when the wire electrode oscillates relatively regularly, as the wire electrode relatively moves from the point A to the point B, the value of the counter unit becomes larger at the point A. The waveform smoothly transitions from the waveform to the point B, and the increments of the two counter portions become substantially the same in the vicinity of the point B, whereby this point can be immediately determined as the contact position to be obtained. At this time, the relative movement between the wire electrode and the workpiece may be stopped.

Further, instead of counting the time of the contact or non-contact state as described above, the average value of the voltage between the wire electrode and the workpiece for a predetermined time, for example, every 10 msec (second) is obtained. The contact position may be determined by stopping the relative movement between the wire electrode and the workpiece when the applied voltage becomes approximately 略. Also,
Each of the above set values is merely an example, and is not limited to these.

[0052]

As described above, according to the method and the apparatus for positioning a wire electric discharge machine of the present invention, the following excellent operational effects can be exhibited. The wire electrode is run to make it in the same situation as during machining, and the forward / backward servo operation keeps the contact / separation repeatedly and keeps the state without sticking, so the detection point always changes due to the vibration of the wire electrode. Despite there, exactly the pressure
Move the tip of the workpiece to the center of the vibration width of the wire electrode
The reference position of the electric discharge machining can be determined. In addition, a wide allowable range is determined based on the coordinates at which the wire electrode and the workpiece first contact each other, and a plurality of coordinate values detected by setting a narrow allowable range that can be updated due to an error within this range are set. Since the center position of the vibration width was determined,
Its accuracy can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a positioning device of a wire electric discharge machine according to the present invention.

FIG. 2 is a block diagram showing a control unit of the positioning device shown in FIG.

FIG. 3 is a flowchart showing parallel processing performed by the positioning device.

FIG. 4 is a flowchart showing vibration center movement control.

FIG. 5 is a diagram illustrating a relationship between vibration of a wire electrode and a contact detection signal.

FIG. 6 is a graph showing a relationship between a vibration of a wire electrode and a count value of each counting unit.

FIG. 7 is a flowchart showing a calculation process for obtaining a contact position.

FIG. 8 is a diagram for explaining various error situations.

FIG. 9 is a schematic configuration diagram showing a positioning device of a conventional wire electric discharge machine.

[Explanation of symbols]

 2 XY table 6 Wire electrode 24 Upper guide 26 Lower guide 32 Contact detection unit 34 Encoder 36 Drive motor 41 Moving mechanism control unit 42 Positioning device 44 Contact state count unit 46 Non-contact state count unit 48 Move control unit 52 First Initial coordinate storage unit 54 Second initial coordinate storage unit 56 Wide area allowable range storage unit 58 Narrow area allowable range storage unit 60 First initial coordinate comparison unit 62 Second initial coordinate comparison unit 63 Coordinate comparison unit 64 Continuous value counter unit 64A Continuous increase counter 64B Continuous decrease counter 66 Continuous value comparator 66A Continuous increase comparator 66B Continuous decrease comparator 68 Coordinate detection count storage unit 70 Coordinate storage unit 72 Reset unit 74 Detection count comparison unit 76 Contact position calculation processing unit 80 Error count Storage unit 82 Error count comparison unit W Workpiece

Continuation of the front page (72) Inventor Tatsuo Toyonaga 3-12-1 Nakamachidai, Tsuzuki-ku, Yokohama-shi, Kanagawa Prefecture Sodick Technical Training Center Co., Ltd. Examiner Takayuki Kanzaki (56) References JP-A-3-281150 (JP, A) JP-A-1-281822 (JP, A) JP-A-4-81908 (JP, A) JP-A-62-124828 (JP, A) JP-A-62-63017 (JP, A) (58) (Int.Cl. ⁷ , DB name) B23H 7/04 B23H 7/02 B23H 7/14

Claims (8)

(57) [Claims] 1. A method for positioning a wire electric discharge machine, wherein a wire electrode stretched between a pair of wire guides and a workpiece are relatively moved to perform electric discharge machining, wherein the wire electrode is run under a predetermined tension. steps and the and away step <br/> are relatively moved so as to approach with respect to the wire electrode and the workpiece, wherein by applying a detection voltage to between the front Symbol wire electrode and said workpiece Detects the voltage between the wire electrode and the workpiece
Step a, the wire electrode is said to be based on the detected voltage
At the center of the vibration width of the wire electrode at the tip of the workpiece
The wire electrode against the workpiece so that it stays in place
Moving the wire electrode relatively to the workpiece.
Or during retraction, the wire electrode and the workpiece
Repeatedly detecting the relative position of the wire electrode; and detecting the vibration of the wire electrode based on the detected relative position.
Determine the center position of the moving width and determine it as the reference position for EDM
A step for positioning the wire electrode and the workpiece.
And a positioning method for a wire electric discharge machine. 2. The method according to claim 1, wherein the wire electrode is connected to the workpiece.
The step of relatively moving forward or backward includes the detecting step.
The wire electrode and the workpiece are separated based on the applied voltage.
The contact state that is in contact and the non-contact state that is not in contact
The contact state and the non-contact state are detected separately.
Counting the number of state detections; and
That the counted value of has reached the preset value
So that the wire electrode and the workpiece are separated from each other.
Relative to the wire electrode and the workpiece,
The counted value in the non-contact state has reached the set value
Sometimes the wire electrode and the workpiece approach
Move the wire electrode and the workpiece relative to each other
2. The wire discharge of claim 1, comprising the steps of:
How to position the processing machine. 3. The method according to claim 1, wherein the wire electrode is connected to the workpiece.
In the positioning step, the coordinate value of the relative position is set in advance.
Setting a predetermined number of times steps rather even store acquired was
And the average value of the stored coordinate values of the plurality of relative positions.
Calculate the center position of the vibration width of the wire electrode and release
Setting a reference position for electrical machining.
A method for positioning a wire electric discharge machine according to claim 1 . 4. The method according to claim 1, wherein the wire electrode and the workpiece are first
Phase between the wire electrode and the workpiece when contacting
Step for storing the coordinate value of the paired position as the first initial coordinate
And the coordinate value of the relative position detected next is
Storing the coordinates as initial coordinates; and
The coordinate value of the relative position is set based on the first initial coordinates
Based on the wide allowable range and the second initial coordinates
When any of the set narrow range tolerances is deviated,
When the stored coordinate values of the relative positions are cleared
In both cases, the coordinate value of the relative position detected next is also updated.
Storing as a second initial coordinate value.
The method for positioning a wire electric discharge machine according to claim 3, comprising : 5. A coordinate value of a relative position to be detected,
Next, by comparing with the coordinate value of the relative position detected,
The coordinate value of the relative position continuously exceeds a set number of times.
When increasing or decreasing, the stored relatives
Clearing the coordinate values of the location.
Item 4. The method for positioning a wire electric discharge machine according to Item 3 . 6. A wire stretched between a pair of wire guides.
Wire supply / transfer means for moving the wire electrode, and the wire
A tension applying mechanism for applying a predetermined tension to the electrode;
Moving device for relatively moving the wire electrode and the workpiece
And a voltage is applied between the wire electrode and the workpiece.
A processing voltage supply unit for supplying the wire electrode and the workpiece
A contact detection unit for detecting a voltage between the object and the object.
In the positioning device of the electric discharge machine, the wire is detected based on the voltage detected by the contact detection unit.
The electrode is vibrated by the wire electrode at the tip of the workpiece.
The wire electrode so that it stays at the center of the dynamic width
To move forward or backward relative to the workpiece
A moving mechanism control unit for driving and controlling the moving mechanism, before to remain in the center position of the vibration width of the wire electrode
Moving the wire electrode relative to the workpiece;
The word ear electrostatic continuously detected in a state that recession
The coordinate values of the relative position between the pole and the workpiece are sequentially stored.
A coordinate storage unit, and coordinates of the plurality of relative positions stored in the coordinate storage unit
Calculate the average value and determine it as the reference position for EDM
That the contact position calculating section and comprises a wire electric discharge machine of the positioning device. 7. The moving mechanism, wherein the wire electrode and the wire electrode
Counts the number of times that contact with the workpiece is detected.
A contact state counting section for counting,
Number of times that it was detected that the workpiece was in non-contact
A non-contact state counting unit for counting the
The moving mechanism control unit determines that the count value of the contact state counting unit is
Outputs the reverse pulse every time the preset value is reached
And the count value of the non-contact state counting section is predicted.
Output a forward pulse every time the set value is reached
7. The wire according to claim 6, wherein
Positioning device for electric machine. 8. A wire stretched between a pair of wire guides.
Wire supply / transfer means for moving the wire electrode, and the wire
A tension applying mechanism for applying a predetermined tension to the electrode;
Moving device for relatively moving the wire electrode and the workpiece
And a voltage is applied between the wire electrode and the workpiece.
A processing voltage supply unit for supplying the wire electrode and the workpiece
A contact detection unit for detecting a voltage between the object and the object.
In the positioning device of the electric discharge machine, the wire is detected based on the voltage detected by the contact detection unit.
An ear electrode is provided at the tip of the workpiece with the wire electrode
The wire electrode so that it stays at the center of the vibration width of
Move forward or backward relative to the workpiece
A moving mechanism control unit that drives and controls the moving mechanism, when the wire electrode and the workpiece first contact with each other.
Relative position of the wire electrode and the workpiece to be detected
A first initial coordinate storing the coordinate values of
The mark storage unit and the wire electrode so as to stay at the center position of the vibration width.
Moving the wire electrode relative to the workpiece;
Is the wire electric wire which is continuously detected in the retracted state.
The coordinate values of the relative position between the pole and the workpiece are sequentially stored.
A coordinate storage unit, the wire electrode and the workpiece, which are continuously detected,
The relative position detected first among the coordinate values of the relative position
Storing the coordinate value of the position as the second initial coordinate,
Every time a predetermined error is detected, it is detected next
A second initial position whose content is updated to the coordinate value of the relative position
A target storage unit and a wide allowable range set based on the first initial coordinates
And a narrow area allowable range set based on the second initial coordinates.
And a narrow-range allowable range storage unit that stores the coordinate value of the relative position newly detected is the wide- range allowable range.
First initial to output error signal when out of range
A coordinate comparison unit, wherein the coordinate value of the newly detected relative position is the narrow area
A second output of an error signal when deviating from the allowable range;
The initial coordinate comparison unit compares the coordinate values of the two consecutively input relative positions with each other.
A coordinate value comparison unit to be compared, and the coordinate value of the relative position is
When it is within the range allowable range and within the narrow range allowable range
The relative position based on the output of the coordinate value comparing unit.
A continuous increment that counts the number of times the coordinate value increases continuously
The number of times the coordinate value between the counter and the relative position continuously decreases.
A continuous value cow including a continuous decrement counter for counting the number.
And when the count value of the continuous value counter section reaches a predetermined value.
Continuous value comparing section for outputting an error signal and the detection times of the coordinate values of the relative position where the is continuously detected
A coordinate detection count storage unit for storing a number, and the coordinates of the relative position that are continuously detected and input.
A coordinate storage unit for sequentially storing values, the first initial coordinate comparing unit, and the second initial coordinate comparing unit
The error signal is output from the unit or the continuous value comparison unit.
To clear the contents of the coordinate
The setting section and the number of detections stored in the coordinate detection number storage section are predetermined.
Detection that outputs a comparison signal when the specified number of times is reached
A number comparison unit, and the coordinate storage unit according to an output from the detection number comparison unit
Calculates the average of the relative position coordinate values stored in the
A contact position calculation processing unit that determines a reference position for machining, and a positioning device for a wire electric discharge machine.