JP6150966B1 - Wire electric discharge machine and control device for wire electric discharge machine - Google Patents

Abstract

The wire electric discharge machine (1) crosses the wire electrode (10) that generates electric discharge between the workpiece (W), the wire electrode (10), and the workpiece (W) with the longitudinal direction of the wire electrode (10). A drive unit (40) for moving the wire electrode (10) in the longitudinal direction, and a wire moving unit (20) for moving the wire electrode (10) in the longitudinal direction. The wire electric discharge machine (1) includes a relative position measuring unit (90) that measures a relative position between the wire electrode (10) and the workpiece (W), and a control device (100). The control device (100) moves the wire electrode (10) to the wire moving section (20) to stop the movement of the wire electrode (10), and causes the tension applying section (50) to perform the electric discharge machining on the wire electrode (10). Apply the same tension as. The control device (100) causes the drive unit (40) to bring the wire electrode (10) and the work (W) closer to each other, and the relative position measurement unit (90) includes the wire electrode (10) and the work (W). The operation of measuring the relative position at the time of contact is repeated.

Description

  The present invention relates to a wire electric discharge machine that applies a machining voltage between a wire electrode and a workpiece to perform electric discharge machining on the workpiece, and a control device for the wire electric discharge machine.

  The wire electric discharge machine needs to accurately measure the relative position between the wire electrode and the workpiece prior to machining. As shown in Patent Document 1, the wire electric discharge machine generally uses a method of measuring the relative position between the wire electrode and the workpiece by detecting electrical contact between the wire electrode and the workpiece.

Japanese Patent No. 2832398

  When the wire electric discharge machine described in Patent Document 1 is moved along the longitudinal direction of the wire electrode, the wire electrode vibrates due to the clearance between the wire electrode and the guide, and the relative position between the wire electrode and the workpiece is determined. Since it is difficult to measure, the workpiece is brought into contact with the wire electrode while the wire electrode is stopped, and the relative position between the wire electrode and the workpiece is measured. Moreover, when measuring the relative position between the wire electrode and the workpiece, the wire electric discharge machine described in Patent Document 1 applies the same tension to the wire electrode as in the electric discharge machining, so that the wire electrode and the workpiece are relatively aligned. The position is about to be close to the same relative position as in the electric discharge machining.

  However, the wire electric discharge machine described in Patent Document 1 can change the relative position of the wire electrode with respect to the guide by the clearance between the wire electrode and the guide. For this reason, the wire electric discharge machine described in Patent Document 1 may shift the relative position between the wire electrode and the workpiece during electric discharge machining from the relative position measured in a state where the wire electrode is stopped. There was a problem that it became difficult to perform electric discharge machining accurately.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a wire electric discharge machine capable of approaching the relative position during electric discharge machining when measuring the relative position between the wire electrode and the workpiece. And

  In order to solve the above-described problems and achieve the object, the present invention is a wire electric discharge machine including a relative position measurement unit that measures a relative position between a wire electrode and a workpiece, and a control device. The control device performs the operation in which the relative position measuring unit measures the relative position at the time of contact when the wire electrode and the workpiece are in contact with each other by changing the position of the wire electrode in contact with the workpiece in the longitudinal direction of the wire electrode. repeat.

  The wire electric discharge machine according to the present invention has an effect that the relative position between the wire electrode to be measured and the workpiece can be brought close to the relative position at the time of electric discharge machining.

The figure which shows the structure of the wire electric discharge machine which concerns on Embodiment 1 of this invention. The figure which shows the state which stopped the wire electrode of the wire electric discharge machine shown in FIG. The figure which shows the state which is moving the wire electrode shown by FIG. The top view which shows the workpiece | work hold | maintained at the workpiece holding part of the wire electric discharge machine shown by FIG. The flowchart which shows a part of process of measuring the relative position at the time of the wire electrode and workpiece | work of the wire electric discharge machine which concern on Embodiment 1 of this invention contact mutually. The flowchart which shows the remainder of the process of measuring the relative position at the time of the wire electrode and workpiece | work of the wire electric discharge machine which concern on Embodiment 1 of this invention which mutually contact. The figure which shows the measurement result of the relative position at the time of the wire electrode and workpiece | work of the wire electric discharge machine which concern on Embodiment 1 of this invention contact mutually. The flowchart which shows a part of process of measuring the relative position at the time of the wire electrode and workpiece | work of the wire electric discharge machine which concern on Embodiment 2 of this invention contact mutually. The flowchart which shows a part of process of measuring the relative position at the time of the contact which the wire electrode and workpiece | work contact of the wire electric discharge machine which concerns on Embodiment 3 of this invention mutually. The flowchart which shows a part of process of measuring the relative position at the time of the contact which the wire electrode and workpiece | work of the wire electric discharge machine concerning Embodiment 4 of this invention contact mutually. The figure which shows an example of the structure of the hardware of the control apparatus of the wire electric discharge machine which concerns on each embodiment The figure which shows the structure which implement | achieved the function of the contact detection part of the wire electric discharge machine which concerns on each embodiment with hardware.

  Hereinafter, a wire electric discharge machine and a control apparatus for the wire electric discharge machine according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a wire electric discharge machine according to Embodiment 1 of the present invention. FIG. 2 is a view showing a state in which the wire electrode of the wire electric discharge machine shown in FIG. 1 is stopped. FIG. 3 is a diagram illustrating a state in which the wire electrode illustrated in FIG. 2 is being moved.

  The wire electric discharge machine 1 is an apparatus for performing wire electric discharge machining on a workpiece W. As shown in FIG. 1, the wire electrode 10 serving as a discharge electrode and the wire electrode 10 are moved along the longitudinal direction of the wire electrode 10. A wire moving unit 20, a workpiece holding unit 30 that holds the workpiece W, and a drive unit 40 that relatively moves the wire electrode 10 and the workpiece W. The wire electric discharge machine 1 includes a tension applying unit 50 that applies tension to the wire electrode 10, a relative position measuring unit 90 that measures a relative position between the wire electrode 10 and the workpiece W, and each configuration of the wire electric discharge machine 1. A control device 100 for controlling elements is provided.

  The wire electrode 10 generates electric discharge between the workpiece W and a machining voltage. The wire electrode 10 is made of a conductive metal and is formed in a long shape. The cross-sectional shape of the wire electrode 10 is formed in a circular shape. In the first embodiment, the outer diameter of the wire electrode 10 is 20 μm or more and 300 μm or less.

  The wire moving unit 20 includes a wire bobbin 21 that winds and supplies the wire electrode 10, a plurality of wire feed rollers 22, a machining head 24 that includes an upper nozzle 23 that feeds the wire electrode 10 toward the workpiece W, and a wire electrode 10 and a collection roller 26 for collecting the wire electrode 10. The wire feed roller 22 is supported so as to be rotatable around an axis. At least one wire feed roller 22 is provided between the wire bobbin 21 and the machining head 24, and the wire electrode 10 is wound to guide the wire electrode 10 from the wire bobbin 21 to the machining head 24. At least one wire feed roller 22 is provided between the lower nozzle 25 and the collection roller 26, and the wire electrode 10 is wound to guide the wire electrode 10 from the lower nozzle 25 to the collection roller 26. The wire feed roller 22 rotates as the wire electrode 10 moves.

  The machining head 24 is attached to the head main body 24a through which the wire electrode 10 is passed, the contact 24b provided on the head main body 24a and in contact with the wire electrode 10, and the lower surface of the head main body 24a facing the workpiece W. And a nozzle 23. As shown in FIGS. 2 and 3, the upper nozzle 23 includes a guide hole 23 a through which the wire electrode 10 is passed. A difference D1 between the inner diameter of the guide hole 23a and the outer diameter of the wire electrode 10 is several μm.

  The lower nozzle 25 is disposed below the upper nozzle 23 of the processing head 24. As shown in FIGS. 2 and 3, the lower nozzle 25 includes a guide hole 25 a through which the wire electrode 10 is passed. A difference D2 between the inner diameter of the guide hole 25a and the outer diameter of the wire electrode 10 is several μm. The upper nozzle 23 and the lower nozzle 25 support the wire electrode 10 linearly between the upper nozzle 23 and the lower nozzle 25 by passing the wire electrode 10 through the guide holes 23a and 25a. In the first embodiment, the upper nozzle 23 and the lower nozzle 25 are opposed to each other with an interval in the vertical direction, and support the wire electrode 10 between the upper nozzle 23 and the lower nozzle 25 in parallel with the vertical direction. The direction in which the upper nozzle 23 and the lower nozzle 25 face each other and the longitudinal direction of the wire electrode 10 between the upper nozzle 23 and the lower nozzle 25 may intersect the vertical direction.

  The collection roller 26 sandwiches the wire electrode 10 with the wire feed roller 22 and is rotated by a wire collection motor 27. The recovery roller 26 is rotated by a wire recovery motor 27 when performing electrical discharge machining on the workpiece W, so that the wire electrode 10 passed through the guide hole 23a of the upper nozzle 23 and the guide hole 25a of the lower nozzle 25 is removed. Collect in the collection box 28. The collection roller 26 can change the moving speed of the wire electrode 10 by changing the rotation speed of the wire collection motor 27. The wire recovery motor 27 is controlled so that the moving speed of the wire electrode 10, that is, the rotational speed of the recovery roller 26 becomes a predetermined constant speed during electric discharge machining. The wire recovery motor 27 has a built-in encoder that measures the rotation angle of the recovery roller 26, and outputs the measurement result of the encoder to the control device 100.

  The work holding unit 30 is made of a conductive metal, and the outer edge has a planar shape in a square frame shape. The work holding unit 30 has a flat surface and is arranged in parallel with the horizontal direction. The work holding unit 30 passes the wire electrode 10 between the upper nozzle 23 and the lower nozzle 25 inside.

  The drive unit 40 relatively moves the wire electrode 10 and the workpiece W in a direction intersecting the longitudinal direction of the wire electrode 10 between the nozzles 23 and 25. In the first embodiment, the drive unit 40 includes an X direction orthogonal to the longitudinal direction of the wire electrode 10 between the nozzles 23 and 25 and parallel to the horizontal direction, and a Y direction parallel to the horizontal direction and orthogonal to the X direction. The wire electrode 10 and the workpiece W can be moved relative to each other. The drive unit 40 can move the wire electrode 10 and the workpiece W relatively along the X direction, and can relatively move the wire electrode 10 and the workpiece W along the Y direction. Y-direction drive unit 40Y.

  The X-direction drive unit 40X includes a motor 41X incorporating an encoder, a ball screw (not shown) that is rotated around the axis of the shaft of the motor 41X by the motor 41X, and a ball screw that is not shown in the drawing. And a nut (not shown) attached to the work holding unit 30. The motor 41X is connected to the control device 100 via the amplifier 42. The motor 41X rotates the ball screw around its axis. The encoder built in the motor 41 </ b> X measures the rotation angle of the ball screw and outputs the measurement result to the control device 100. The X-direction drive unit 40 </ b> X moves the workpiece W held by the workpiece holding unit 30 in the X direction with respect to the wire electrode 10 by the motor 41 </ b> X rotating the ball screw around the axis.

  The Y-direction drive unit 40Y includes a motor 41Y including an encoder, a ball screw (not shown) that is rotated around the shaft center of the motor 41Y by the motor 41Y, and extends in a direction parallel to the Y direction. And a nut (not shown) attached to the support plate 31 that supports the motor 41X. The motor 41Y is connected to the control device 100 via the amplifier 42. The motor 41Y rotates the ball screw around its axis. The encoder built in the motor 41Y measures the rotation angle of the ball screw and outputs the measurement result to the control device 100. The support plate 31 is made of a conductive metal, and the outer edge has a planar shape in a square frame shape. The support plate 31 is attached to the motor 41X. The support plate 31 has a flat surface and is arranged in parallel with the horizontal direction. The support plate 31 is disposed at a position where the inner hole communicates with the inner hole of the work holding unit 30, and allows the wire electrode 10 between the upper nozzle 23 and the lower nozzle 25 to pass therethrough. The Y-direction drive unit 40Y causes the work W held by the work holding unit 30 to move to the wire electrode 10 via the motor 41X supported by the support plate 31 when the motor 41Y rotates the ball screw around the axis. To move in the Y direction.

  The drive unit 40 moves the workpiece W in the X direction and the Y direction, so that the workpiece W approaches the wire electrode 10 between the nozzles 23 and 25 or away from the wire electrode 10 between the nozzles 23 and 25. Move the workpiece W. In the first embodiment, the drive unit 40 moves the workpiece W in a direction orthogonal to the longitudinal direction of the wire electrode 10 between the nozzles 23 and 25, but the workpiece W is moved in the longitudinal direction of the wire electrode 10 between the nozzles 23 and 25. You may make it move in the direction which intersects without being orthogonal to. Further, the drive unit 40 may move both the wire electrode 10 between the nozzles 23 and 25 and the workpiece W, and the wire electrode 10 between the nozzles 23 and 25 is moved to the workpiece W without moving the workpiece W. You may move it.

  A machining voltage is applied between the wire electrode 10 and the workpiece W from the power supply 80. The power source 80 is electrically connected to the wire electrode 10 through the contact 24 b and is connected to the work W through the work holding unit 30. The power supply 80 applies a machining voltage between the wire 24 and the workpiece W by applying a machining voltage between the contact 24 b and the workpiece holding unit 30. The machining voltage applied by the power supply 80 is a voltage that breaks the insulation between the wire electrode 10 between the nozzles 23 and 25 and the workpiece W, generates a discharge, and removes a part of the workpiece W by the discharge. In the first embodiment, when the inter-electrode distance, which is the distance between the wire electrode 10 between the nozzles 23 and 25 and the workpiece W, is 10 μm or more and 20 μm or less, the machining voltage is between the wire electrode 10 and the workpiece W. The distance between the electrodes of the wire electrode 10 and the workpiece W is not limited to 10 μm or more and 20 μm or less.

  The tension applying unit 50 applies tension to the wire electrode 10 when a machining voltage is applied to the wire electrode 10 and the workpiece W is subjected to electric discharge machining. The tension applying unit 50 includes a tension applying roller 51 and a main tension motor 52 that can rotate the tension applying roller 51. The tension applying roller 51 is provided between the wire bobbin 21 and the processing head 24, and sandwiches the wire electrode 10 between the wire feed roller 22. The main tension motor 52 rotates the tension applying roller 51 in a direction in which the wire electrode 10 is wound around the wire bobbin 21. The driving torque of the main tension motor 52 is weaker than the driving torque of the wire recovery motor 27. The tension applying unit 50 causes the main tension motor 52 to rotate the tension applying roller 51 with a driving torque weaker than the driving torque of the wire recovery motor 27 when the workpiece W is subjected to electric discharge machining. A tension is applied along the longitudinal direction of the wire electrode 10 between the nozzles 23 and 25. The main tension motor 52 is controlled so that the tension applied to the wire electrode 10 at the time of electric discharge machining becomes a predetermined constant tension.

  The relative position measurement unit 90 detects the relative position between the X-direction linear scale 60 </ b> X that detects the relative position between the X-direction workpiece holding unit 30 and the wire electrode 10, and the Y-direction workpiece holding unit 30 and the wire electrode 10. A Y-direction linear scale 60 </ b> Y and a contact detection unit 70 that detects electrical contact between the workpiece W and the wire electrode 10 are provided. The X-direction linear scale 60X includes a linear scale 61X that is parallel to the X direction, and a detector 62X that is provided on the scale 61X so as to be movable in the X direction and is fixed to the work holding unit 30. The X-direction linear scale 60X measures the relative position in the X direction between the workpiece W and the wire electrode 10 by measuring the position of the detector 62X with respect to the scale 61X. The X-direction linear scale 60X outputs the measurement result to the control device 100.

  The Y-direction linear scale 60Y includes a linear scale 61Y that is parallel to the Y direction, and a detector 62Y that is provided on the scale 61Y so as to be movable in the Y direction and is fixed to the support plate 31. The Y-direction linear scale 60Y measures the relative position in the Y direction between the workpiece W and the wire electrode 10 by measuring the position of the detector 62Y with respect to the scale 61Y. The Y-direction linear scale 60Y outputs the measurement result to the control device 100.

  The contact detection unit 70 is electrically connected to the wire electrode 10 via the contact 24 b and the workpiece W via the workpiece holding unit 30. The contact detection unit 70 includes a potential difference applying unit 71 that applies a potential difference between the wire electrode 10 and the workpiece W, and a detection unit 72 that measures a potential difference between the wire electrode 10 and the workpiece W. The potential difference applied between the wire electrode 10 and the workpiece W by the potential difference applying unit 71 is a potential difference at which no discharge occurs between the wire electrode 10 and the workpiece W. When the detection unit 72 detects that the potential difference between the wire electrode 10 and the workpiece W has changed, the contact detection unit 70 detects that the potential difference has changed, that is, electrical contact between the wire electrode 10 and the workpiece W. The detection result is output to the control device 100.

  Thus, the relative position between the wire electrode 10 and the workpiece W measured by the relative position measuring unit 90 is the position of the detectors 62X and 62Y with respect to the scales 61X and 61Y of the linear scales 60X and 60Y.

  The control device 100 is a numerical control device that generates a machining condition by executing a numerical control program and outputs the machining condition to each part of the wire electric discharge machine 1, thereby operating each part of the wire electric discharge machine 1. Is controlled to perform electric discharge machining on the workpiece W. The control device 100 executes a numerical control program before performing electric discharge machining on the workpiece W, thereby measuring a relative position at the time of contact between the wire electrode 10 in each of the X direction and the Y direction and the workpiece W. That is, the control device 100 performs an operation in which the relative position measuring unit 90 measures the relative position at the time of contact when the wire electrode 10 and the workpiece W are in contact with each other. Repeat several times with different lengths.

  In the first embodiment, the control device 100 measures the information necessary for generating the machining conditions and the relative position at the time of contact between the wire electrode 10 and the workpiece W in the X direction and the Y direction, respectively. An input device 101 is connected to input information necessary for the operation. The control device 100 is connected to a display device 102 for displaying a relative position at the time of contact where the wire electrode 10 and the workpiece W in the X direction and the Y direction contact each other. Further, the wire electric discharge machine 1 includes a machining liquid supply unit (not shown) that supplies a machining liquid to the wire electrode 10 between the nozzles 23 and 25.

  The wire electric discharge machine 1 having the above-described configuration starts a machining operation when information necessary for generating machining conditions is input from the input device 101 to the control device 100 and a machining start command is input. In the machining operation, the wire electrode 10 and the workpiece W are positioned based on the relative positions at the time of contact between the wire electrode 10 and the workpiece W in the X direction and the Y direction, respectively. After positioning the wire electrode 10 and the workpiece W, the control device 100 generates a processing condition based on the input information, and the generated processing condition is determined based on the driving unit 40, the wire moving unit 20, the tension applying unit 50, and the power supply. Output to 80. Then, in the wire electric discharge machine 1, the power source 80 applies a machining voltage between the wire electrode 10 and the workpiece W, applies tension to the wire electrode 10, and moves the wire electrode 10 in the longitudinal direction. Electric discharge is generated between the workpiece 10 and the workpiece W, and the workpiece W is subjected to electric discharge machining.

  In the wire electric discharge machine 1, before the wire electrode 10 is moved by the wire moving unit 20, the wire electrode 10 is stopped between the nozzles 23 and 25 as shown in FIG. When the wire electric discharge machine 1 moves the wire electrode 10 along the longitudinal direction by the wire moving unit 20, the solid line in FIG. 3 is obtained due to the differences D1 and D2 between the outer diameter of the wire electrode 10 and the inner diameters of the nozzles 23 and 25. As shown, the wire electrode 10 vibrates in a direction orthogonal to the moving direction of the wire electrode 10 between the nozzles 23 and 25. Since the wire electrode 10 vibrates during the electric discharge machining due to the differences D1 and D2 between the outer diameter of the wire electrode 10 and the inner diameters of the nozzles 23 and 25, the wire electric discharge machine 1 has X and Y directions before electric discharge machining. It is necessary to measure the relative position when the wire electrode 10 and the workpiece W are in contact with each other with high accuracy.

  Next, a process of measuring the relative position at the time of contact where the wire electrode 10 and the workpiece W in the X direction and the Y direction of the wire electric discharge machine 1 according to Embodiment 1 are in contact with each other will be described based on the drawings. FIG. 4 is a plan view showing the work held by the work holding unit of the wire electric discharge machine shown in FIG. FIG. 5 is a flowchart showing a part of a process of measuring the relative position at the time of contact between the wire electrode and the workpiece of the wire electric discharge machine according to Embodiment 1 of the present invention. FIG. 6 is a flowchart showing the remainder of the process of measuring the relative position during contact when the wire electrode and the workpiece contact each other in the wire electric discharge machine according to Embodiment 1 of the present invention.

  In the first embodiment, the wire electric discharge machine 1 uses the one corner of the workpiece W shown in FIG. 4 as the reference position SP, and makes the wire electrode 10 contact the reference position SP, whereby the X direction and the Y of the reference position SP are set. The position in each direction is measured, and the relative position between the wire electrode 10 and the workpiece W is measured. In the first embodiment, the reference position SP is one corner of the workpiece W, but the reference position SP can be set to an arbitrary position of the workpiece W. When measuring the relative position between the wire electrode 10 and the workpiece W, the control device 100 of the wire electric discharge machine 1 first receives a measurement direction for measuring the relative position from the input device 101 (step S1). In step S1, the accepted measurement direction is the X direction or the Y direction.

  The control device 100 of the wire electric discharge machine 1 causes the wire moving unit 20 to stop the wire electrode 10 and supplies the machining liquid to the machining liquid supply unit (step S2). The control device 100 of the wire electric discharge machine 1 causes the tension applying unit 50 to apply the same tension to the wire electrode 10 as in the electric discharge machining (step S3). The control device 100 of the wire electric discharge machine 1 causes the drive unit 40 to move the workpiece W in the direction approaching the wire electrode 10 at the first movement speed along the measurement direction received in step S1 (step S4).

  The control device 100 of the wire electric discharge machine 1 determines whether or not the contact detection unit 70 has detected an electrical contact between the wire electrode 10 and the workpiece W (step S5). When the control device 100 of the wire electric discharge machine 1 determines that the contact detection unit 70 has not detected the electrical contact between the wire electrode 10 and the workpiece W (step S5: No), the control device 100 returns to step S4 and contacts. Steps S4 and S5 are repeated until it is determined that the detection unit 70 has detected electrical contact between the wire electrode 10 and the workpiece W.

  When the control device 100 of the wire electric discharge machine 1 determines that the contact detection unit 70 has detected an electrical contact between the wire electrode 10 and the workpiece W (step S5: Yes), the workpiece W is wired to the drive unit 40. The position is retracted to a position where contact with the electrode 10 is avoided (step S6). In the first embodiment, the control device 100 of the wire electric discharge machine 1 separates the workpiece W from the wire electrode 10 to the driving unit 40 until the contact detection unit 70 does not detect the contact between the wire electrode 10 and the workpiece W. Thereafter, the workpiece W is moved to the drive unit 40 in a direction in which the workpiece W is separated from the wire electrode 10 by a preset distance. The preset distance is determined according to the differences D1 and D2 between the outer diameter of the wire electrode 10 and the inner diameters of the nozzles 23 and 25, and the workpiece W and the wire electrode 10 are not reliably in contact with each other. This is the distance at which the workpiece W and the wire electrode 10 are positioned as close as possible.

  The control device 100 of the wire electric discharge machine 1 moves the wire electrode 10 to the wire moving unit 20 (step S7). Based on the measurement result of the encoder of the wire recovery motor 27, the control device 100 of the wire electric discharge machine 1 determines whether or not the wire electrode 10 has moved a specified distance set in advance from the start of the movement in step S7 (step S7). S8). When the control device 100 of the wire electric discharge machine 1 determines that the wire electrode 10 has not moved by the preset designated distance (step S8: No), the control device 100 returns to step S7 until the wire electrode 10 moves by the designated distance. Steps S7 and S8 are repeated. In the first embodiment, the specified distance is the distance between the nozzles 23 and 25, but may be the thickness of the workpiece W along the longitudinal direction of the wire electrode 10 between the nozzles 23 and 25. Further, in step S8, the control device 100 determines whether or not a predetermined time set in advance has elapsed since the start of the movement of the wire electrode 10 by the wire moving unit 20 in step S7 instead of the specified distance. Also good.

  When the control device 100 of the wire electric discharge machine 1 determines that the wire electrode 10 has moved a predetermined distance set in advance (step S8: Yes), the wire moving unit 20 stops the movement of the wire electrode 10 (step S9). ). The control device 100 of the wire electric discharge machine 1 has a second movement speed that is lower than the first movement speed in the direction in which the workpiece W approaches the wire electrode 10 to the drive unit 40 along the measurement direction received in step S1. Move (step S10). In the first embodiment, the second moving speed in step S10 is the moving speed at which the workpiece W moves a preset distance during the sampling time for detecting the contact between the wire electrode 10 of the contact detection unit 70 and the workpiece W. Yes. The preset distance of the workpiece W is determined according to the measurement accuracy of the relative position at the time of contact when the wire electrode 10 and the workpiece W are in contact.

  The control device 100 of the wire electric discharge machine 1 determines whether or not the contact detection unit 70 has detected an electrical contact between the wire electrode 10 and the workpiece W (step S11). When the control device 100 of the wire electric discharge machine 1 determines that the contact detection unit 70 has not detected the electrical contact between the wire electrode 10 and the workpiece W (step S11: No), the control device 100 returns to step S10 and contacts. Steps S10 and S11 are repeated until it is determined that the detection unit 70 has detected electrical contact between the wire electrode 10 and the workpiece W.

  When the control device 100 of the wire electric discharge machine 1 determines that the contact detection unit 70 has detected an electrical contact between the wire electrode 10 and the workpiece W (step S11: Yes), the movement of the workpiece W to the drive unit 40 is performed. Is stopped (step S12). The control device 100 of the wire electric discharge machine 1 makes contact with the measurement result of the linear scales 60X and 60Y corresponding to the measurement direction received in step S1, that is, the wire electrode 10 in the measurement direction received in step S1 and the workpiece W. The relative position at the time of contact is stored (step S13).

  The control device 100 of the wire electric discharge machine 1 determines whether or not the relative position at the time of contact when the wire electrode 10 in the measurement direction received in step S1 and the workpiece W are in contact with each other is stored. (Step S14). The wire electric discharge machine 1 determines that the relative position at the time of contact when the wire electrode 10 in the measurement direction received in step S1 and the workpiece W are in contact with each other is not stored (step S14: No) returns to Step S6, and Steps S6 to S14 are repeated until the relative position at the time of contact when the wire electrode 10 in the measurement direction received in Step S1 and the workpiece W are in contact is stored for a specified number of times. In the first embodiment, the designated number of times is five, but is not limited to five. Thus, the control device 100 of the wire electric discharge machine 1 is configured such that the wire moving unit 20 moves the wire electrode 10 along the longitudinal direction and then stops the movement of the wire electrode 10, and the driving unit 40 is connected to the wire electrode 10. The operation of bringing the workpiece W closer to each other and the operation of the relative position measuring unit 90 measuring the relative position at the time of contact when the wire electrode 10 and the workpiece W are in contact are repeated in order several times.

  The control device 100 of the wire electric discharge machine 1 determines that the relative position at the time of contact when the wire electrode 10 in the measurement direction received in step S1 and the workpiece W are in contact is stored (step S1). S14: Yes), and the contact relative position that can be regarded as noise is removed from the stored contact relative positions for the designated number of times (step S15). In the first embodiment, the control device 100 of the wire electric discharge machine 1 calculates the average value of the contact relative positions for the specified number of times stored and the variance value of each contact relative position, and each contact relative position. The relative position at the time of contact exceeding the sum of the average value and the value determined according to the difference D1, D2 between the outer diameter of the wire electrode 10 and the inner diameter of the nozzles 23, 25 is defined as noise.

  The control device 100 of the wire electric discharge machine 1 calculates an average value of the contact relative position excluding the contact relative position removed as noise, and the average value is a relative position where the wire electrode 10 and the workpiece W are in contact with each other. (Step S16). As described above, the control device 100 of the wire electric discharge machine 1 determines the wire based on the contact relative position when the wire electrode 10 and the workpiece W contacted by the relative position measurement unit 90 a plurality of times in Step S16. The relative position between the electrode 10 and the workpiece W is calculated.

  The control device 100 of the wire electric discharge machine 1 moves the workpiece W to the drive unit 40 to the relative position where the wire electrode 10 and the workpiece W which are the average values calculated in step S16 are in contact with each other. The relative position where the wire electrode 10 and the workpiece W are in contact with each other is displayed on the display device 102 (step S17), and the flowcharts of FIGS. 5 and 6 are ended. In the first embodiment, the average value of the contact relative position calculated in step S15 and the average value of the contact relative position calculated in step S16 are arithmetic average values, but may be geometric mean values. .

  The wire electric discharge machine 1 and the control device 100 execute step S3 and repeat the steps S6 to S14 for the designated number of measurements to move the wire electrode 10 to the wire moving unit 20 along the longitudinal direction. In a state where the movement of the wire electrode 10 is stopped and the tension applying unit 50 is applied with the same tension as that in the electric discharge machining, the driving unit 40 brings the wire electrode 10 and the workpiece W closer to each other, The operation of causing the position measuring unit 90 to measure the relative position at the time of contact when the wire electrode 10 and the workpiece W are in contact is repeated a plurality of times.

  As described above, the wire electric discharge machine 1 and the control device 100 according to Embodiment 1 stop the movement of the wire electrode 10 after moving the wire electrode 10 along the longitudinal direction in the wire moving unit 20. With the tension applied to the wire applying force applied to the wire electrode 10 applied to the tension applying unit 50, the wire electrode 10 and the work W are brought close to the drive unit 40, and the wire electrode 10 and the work are applied to the relative position measuring unit 90. The operation of measuring the relative position at the time of contact with W is repeated a plurality of times. For this purpose, the wire electric discharge machine 1 and the control device 100 move the wire electrode 10 in the longitudinal direction while measuring the relative position between the wire electrode 10 and the workpiece W, so that the relative relationship between the wire electrode 10 and the workpiece W is increased. The positions of the wire electrodes 10 in the nozzles 23 and 25 at each measurement time for measuring the position can be dispersed within the range of the aforementioned differences D1 and D2. As a result, when measuring the relative position between the wire electrode 10 and the workpiece W, the wire electric discharge machine 1 and the control device 100 bring the relative position between the wire electrode 10 and the workpiece W closer to the relative position at the time of electric discharge machining. Can do.

  In addition, the wire electric discharge machine 1 and the control device 100 according to the first embodiment causes the wire moving unit 20 to move the wire electrode 10 along the longitudinal direction by a specified distance, and then stops the movement of the wire electrode 10, thereby increasing the tension. And the operation of measuring the relative position between the wire electrode 10 and the workpiece W is repeated a plurality of times, so that the relative position is not detected or the portion of the wire electrode 10 that is not subjected to electric discharge machining and the workpiece W Measure the relative position of. For this reason, the wire electric discharge machine 1 and the control device 100 do not measure the relative position between a part of the wire electrode 10 and the workpiece W that have been corroded by applying the machining voltage, and the contact of the workpiece W The relative position between a part of the bent wire electrode 10 and the workpiece W is not measured. As a result, the wire electric discharge machine 1 and the control device 100 can accurately measure the relative position between the wire electrode 10 and the workpiece W.

  Further, the wire electric discharge machine 1 and the control device 100 according to the first embodiment remove the relative position at the time of contact that can be regarded as noise among the relative positions at the time of contact between the wire electrode 10 and the workpiece W of the designated number of times. Therefore, the exact relative position between the wire electrode 10 and the workpiece W can be measured. Further, the wire electric discharge machine 1 and the control device 100 according to the first embodiment measure the relative position at the time of contact when the wire electrode 10 and the workpiece W are brought close to each other and contacted in steps S10 and S11. Further, the wire moving unit 20 stops the movement of the wire electrode 10. For this reason, since the wire electrode 10 does not vibrate when measuring the relative position during contact, the wire electric discharge machine 1 and the control device 100 according to Embodiment 1 move the wire electrode 10 along the longitudinal direction. Measurement time can be shortened compared with the case of measuring.

  Next, the wire electrode measured when the control device 100 of the wire electric discharge machine 1 according to the first embodiment executes the process up to step S14 of the flowchart shown in FIGS. FIG. 7 shows the relative position to the workpiece. FIG. 7 is a diagram showing the measurement result of the relative position at the time of contact between the wire electrode and the workpiece of the wire electric discharge machine according to Embodiment 1 of the present invention.

  The trial times on the horizontal axis in FIG. 7 indicate the respective measurement times executed up to step S14 in the flowcharts shown in FIGS. 5 and 6, and the vertical axis in FIG. 7 indicates the wire electrode 10 measured in each measurement time. The relative position at the time of contact with the workpiece W is shown in arbitrary units. FIG. 7 shows a relative position at the time of contact when the measured wire electrode 10 and the workpiece W are in contact with each other by a rhombus, and the relative position at the time of contact when the measured wire electrode 10 and the workpiece W are in contact at each measurement time. Average values are indicated by black circles. FIG. 7 shows a range of variation in positioning results that can be measured by double arrows.

  According to FIG. 7, the wire electric discharge machine 1 and the control device 100 execute the flowcharts shown in FIGS. 5 and 6, so that the outer diameter of the wire electrode 10 and the inner diameters of the nozzles 23 and 25 are determined at each measurement time. It was found that the relative position at the time of contact when the wire electrode 10 and the workpiece W contact each other varies within the range in which the wire position deviation caused by the difference D1 and D2 and the measurement error are combined. Further, according to FIG. 7, the wire electric discharge machine 1 and the control device 100 execute the control according to the flowcharts shown in FIGS. 5 and 6, so that the average value of each measurement time becomes the outer diameter of the wire electrode 10 and the nozzle. It became clear that it approached the center in the range which combined the wire position shift and measurement error resulting from difference D1, D2 with the internal diameter of 23,25. Therefore, according to FIG. 7, the wire electrode 10 is moved along the longitudinal direction to the wire moving unit 20, and then the movement of the wire electrode 10 is stopped, and tension is applied to make the wire electrode 10 and the workpiece W relative to each other. It has been clarified that repeating the position measuring operation a plurality of times can bring the relative position between the wire electrode 10 and the workpiece W when measuring the relative position closer to the relative position during electric discharge machining.

Embodiment 2. FIG.
Next, a wire electric discharge machine 1 according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 8 is a flowchart showing a part of a process of measuring the relative position at the time of contact between the wire electrode and the workpiece of the wire electric discharge machine according to Embodiment 2 of the present invention. In FIG. 8, the same parts as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The wire electric discharge machine 1 according to the second embodiment has the same configuration as that of the first embodiment. The control device 100 of the wire electric discharge machine 1 according to Embodiment 2 causes the wire moving unit 20 to move the wire electrode 10 along the longitudinal direction in order to measure the relative position at the time of contact (step S7). After the tension applied to the wire electrode 10 by the tension applying unit 50 is once weakened than the tension applied during the electric discharge machining, the tension applying unit 50 applies the same tension to the wire electrode 10 as during the electric discharge machining (step S20).

  The control device 100 of the wire electric discharge machine 1 according to the second embodiment executes step S7 after executing step S3. Therefore, when the wire moving unit 20 moves the wire electrode 10 along the longitudinal direction, tension is applied. The applying part 50 is made to apply the same tension to the wire electrode 10 as in the electric discharge machining. The control device 100 of the wire electric discharge machine 1 according to Embodiment 2 causes the drive unit 40 to retract the work W to a position where contact with the wire electrode 10 is avoided so as to avoid contact (Step S6), and then executes Step S20. Step S7 is executed. The control device 100 of the wire electric discharge machine 1 according to the second embodiment performs the same processing as that of the first embodiment except that step S20 and step S7 are sequentially performed after step S6. In the second embodiment, the controller 100 of the wire electric discharge machine 1 causes the tension applying unit 50 to zero the tension applied to the wire electrode 10 in step S20, and then causes the tension applying unit 50 to apply the wire electrode 10 to the tension applying unit 50. Is given the same tension as during EDM.

  As in the first embodiment, the wire electric discharge machine 1 and the control device 100 according to the second embodiment stop the movement of the wire electrode 10 after moving the wire electrode 10 along the longitudinal direction in the wire moving unit 20. The operation of applying the tension and measuring the relative position between the wire electrode 10 and the workpiece W is repeated a plurality of times. As a result, the wire electric discharge machine 1 and the control device 100 according to the second embodiment, as in the first embodiment, determine the relative position between the wire electrode 10 and the workpiece W when measuring the relative position at the time of electric discharge machining. You can approach the relative position.

  In addition, the wire electric discharge machine 1 and the control device 100 according to Embodiment 2 temporarily weaken the tension applied to the wire electrode 10 by the tension applying unit 50 at a timing before Step S7 than the tension at the time of electric discharge machining. After that, the tension applying unit 50 is made to apply the same tension to the wire electrode 10 as in the electric discharge machining. For this purpose, the wire electric discharge machine 1 and the control device 100 according to the second embodiment execute step S7 and step S8 to move the wire electrode 10 in the longitudinal direction and then move the wire electrode 10 and the workpiece W to each other. The position of the wire electrode 10 in the nozzles 23 and 25 for each measurement time for measuring the relative position can be dispersed within the range of the differences D1 and D2. As a result, the wire electric discharge machine 1 and the control device 100 can bring the relative position between the wire electrode 10 and the workpiece W when measuring the relative position closer to the relative position during electric discharge machining.

Embodiment 3 FIG.
Next, a wire electric discharge machine 1 according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 9 is a flowchart showing a part of a process of measuring the relative position at the time of contact between the wire electrode and the workpiece of the wire electric discharge machine according to Embodiment 3 of the present invention. In FIG. 9, the same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The wire electric discharge machine 1 according to the third embodiment has the same configuration as that of the first embodiment. The control device 100 of the wire electric discharge machine 1 according to Embodiment 3 causes the wire moving unit 20 to move the wire electrode 10 along the longitudinal direction in order to measure the relative position during contact (step S7). Then, after the tension applied to the wire electrode 10 by the tension applying unit 50 is once weaker than the tension applied during the electric discharge machining, the tension applying unit 50 applies the same tension to the wire electrode 10 as during the electric discharge machining (step S21).

  The control device 100 of the wire electric discharge machine 1 according to the third embodiment executes step S7 after executing step S3. Therefore, when the wire moving unit 20 moves the wire electrode 10 along the longitudinal direction, tension is applied. The applying part 50 is made to apply the same tension to the wire electrode 10 as in the electric discharge machining. The control device 100 of the wire electric discharge machine 1 according to Embodiment 3 causes the wire moving unit 20 to stop moving the wire electrode 10 (step S9), and then executes step S21 and executes step S10. The control device 100 of the wire electric discharge machine 1 according to the third embodiment performs the same process as that of the first embodiment except that step S21 and step S10 are sequentially performed after step S9. In Embodiment 3, the control device 100 of the wire electric discharge machine 1 causes the tension applying unit 50 to zero the tension applied to the wire electrode 10 in step S21, and then the tension applying unit 50 to the wire electrode 10. Is given the same tension as during EDM.

  As in the first embodiment, the wire electric discharge machine 1 and the control device 100 according to the third embodiment stop the movement of the wire electrode 10 after moving the wire electrode 10 along the longitudinal direction in the wire moving unit 20. The operation of applying the tension and measuring the relative position between the wire electrode 10 and the workpiece W is repeated a plurality of times. As a result, the wire electric discharge machine 1 and the control device 100 according to the third embodiment can determine the relative position between the wire electrode 10 and the workpiece W when measuring the relative position, as in the first embodiment. You can approach the relative position.

  In addition, the wire electric discharge machine 1 and the control device 100 according to the third embodiment temporarily weaken the tension applied to the wire electrode 10 by the tension applying unit 50 at a timing after step S7 than the tension during the electric discharge machining. After that, the tension applying unit 50 is made to apply the same tension to the wire electrode 10 as in the electric discharge machining. For this purpose, the wire electric discharge machine 1 and the control device 100 according to the third embodiment execute step S7 and step S8 to move the wire electrode 10 in the longitudinal direction and then move the wire electrode 10 and the workpiece W to each other. The position of the wire electrode 10 in the nozzles 23 and 25 for each measurement time for measuring the relative position can be dispersed within the range of the differences D1 and D2. As a result, the wire electric discharge machine 1 and the control device 100 can bring the relative position between the wire electrode 10 and the workpiece W when measuring the relative position closer to the relative position during electric discharge machining.

Embodiment 4 FIG.
Next, a wire electric discharge machine 1 according to Embodiment 4 of the present invention will be described with reference to the drawings. FIG. 10 is a flowchart showing a part of a process of measuring the relative position at the time of contact between the wire electrode and the workpiece of the wire electric discharge machine according to Embodiment 4 of the present invention. In FIG. 10, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The wire electric discharge machine 1 according to the fourth embodiment has the same configuration as that of the first embodiment. The control device 100 of the wire electric discharge machine 1 according to Embodiment 4 causes the wire moving unit 20 to move the wire electrode 10 along the longitudinal direction in order to measure the relative position during contact (step S7). After the tension applied to the wire electrode 10 by the tension applying unit 50 is once weakened than the tension applied during the electric discharge machining, the tension applying unit 50 applies the same tension to the wire electrode 10 as during the electric discharge machining (step S20).

  Further, the control device 100 of the wire electric discharge machine 1 according to Embodiment 4 causes the wire moving unit 20 to move the wire electrode 10 along the longitudinal direction in order to measure the relative position at the time of contact (step S7). At a timing, the tension applied by the tension applying unit 50 to the wire electrode 10 is once weakened than the tension applied during the electric discharge machining, and then the tension applying unit 50 applies the same tension as that applied during the electric discharge machining to the wire electrode 10 (step S21). ).

  Since control device 100 of wire electric discharge machine 1 according to the fourth embodiment executes step S7 after executing step S3, the tension is applied when wire actuator 10 moves wire electrode 10 along the longitudinal direction. The applying part 50 is made to apply the same tension to the wire electrode 10 as in the electric discharge machining. The control device 100 of the wire electric discharge machine 1 according to the fourth embodiment causes the drive unit 40 to retract the workpiece W to a position where contact with the wire electrode 10 is avoided (step S6), and then executes step S20. Step S7 is executed. The control device 100 of the wire electric discharge machine 1 according to Embodiment 4 causes the wire moving unit 20 to stop moving the wire electrode 10 (step S9), and then executes step S21 and executes step S10.

  The control device 100 of the wire electric discharge machine 1 according to the fourth embodiment executes step S20 and step S7 in order after step S6, and executes step S21 and step S10 in order after step S9. The same process as in the first mode is executed. In the fourth embodiment, the control device 100 of the wire electric discharge machine 1 causes the tension applying unit 50 to apply the tension applied to the wire electrode 10 to zero in step S20 and step S21, and then to the tension applying unit 50. The wire electrode 10 is given the same tension as that in the electric discharge machining.

  As in the first embodiment, the wire electric discharge machine 1 and the control device 100 according to the fourth embodiment stop the movement of the wire electrode 10 after moving the wire electrode 10 along the longitudinal direction in the wire moving unit 20. The operation of applying the tension and measuring the relative position between the wire electrode 10 and the workpiece W is repeated a plurality of times. As a result, the wire electric discharge machine 1 and the control device 100 according to the fourth embodiment, as in the first embodiment, determine the relative position between the wire electrode 10 and the workpiece W when measuring the relative position. You can approach the relative position.

  Further, the wire electric discharge machine 1 and the control device 100 according to the fourth embodiment temporarily weaken the tension applied to the wire electrode 10 by the tension applying unit 50 at both the timings before and after step S7. Then, the tension applying portion 50 is applied with the same tension as that during the electric discharge machining to the wire electrode 10. For this purpose, the wire electric discharge machine 1 and the control device 100 according to the fourth embodiment execute step S7 and step S8 to move the wire electrode 10 in the longitudinal direction and then move the wire electrode 10 and the workpiece W to each other. The position of the wire electrode 10 in the nozzles 23 and 25 for each measurement time for measuring the relative position can be dispersed within the range of the differences D1 and D2. As a result, the wire electric discharge machine 1 and the control device 100 can bring the relative position between the wire electrode 10 and the workpiece W when measuring the relative position closer to the relative position during electric discharge machining.

  Next, the configuration of the control device 100 of the wire electric discharge machine 1 according to each embodiment will be described. FIG. 11 is a diagram illustrating an example of a hardware configuration of a control device for a wire electric discharge machine according to each embodiment. The control device 100 makes contact with the information necessary for generating machining conditions from the input device 101 connected to the input / output interface 103 shown in FIG. 11, the wire electrode 10 in the X direction and the Y direction, and the workpiece W. Information necessary for measuring the relative position at the time of contact is input. The input device 101 includes a touch panel, a keyboard, a mouse, a trackball, or a combination thereof. The control device 100 displays on the display device 102 connected to the input / output interface 103 the relative position at the time of contact where the wire electrode 10 and the workpiece W in the X direction and Y direction contact each other. In each embodiment, the display device 102 is a liquid crystal display device, but is not limited to a liquid crystal display device.

  As illustrated in FIG. 11, the control device 100 is a computer including a CPU (Central Processing Unit) 104, a memory 105, and an input / output interface 103. The memory 105 stores software, firmware, or a combination of software and firmware as a program. Further, the memory 105 measures information necessary for generating the machining conditions input from the input device 101 and the relative position at the time of contact between the wire electrode 10 and the workpiece W in the X direction and the Y direction, respectively. Information necessary for this purpose is stored. The memory 105 is calculated from the relative position at the time of contact between the wire electrode 10 of each measurement time and the workpiece W detected by the contact detection unit 70 in each of the X direction and the Y direction, and the relative position at the time of contact of a plurality of measurement times. The average value is stored. The memory 105 is composed of a nonvolatile or volatile semiconductor memory, a magnetic disk, an optical disk, or a magneto-optical disk. As the nonvolatile or volatile semiconductor memory, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), or EEPROM (Electrically Erasable Programmable Read-Only Memory) is used. It is done. In the control device 100, the CPU 104 executes the program stored in the memory 105, and realizes the functions described in each embodiment.

  Next, in each embodiment, a method for realizing the function of the contact detection unit 70 will be described. FIG. 12 is a diagram illustrating a configuration in which the function of the contact detection unit of the wire electric discharge machine according to each embodiment is realized by hardware. The function of the contact detection unit 70 is realized by the processing circuit 73 shown in FIG. 12 in each embodiment.

  The processing circuit 73 that realizes the function of the contact detection unit 70 includes a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or A combination of these applies. The processing circuit 73 includes a power supply circuit 74 that implements the potential difference applying unit 71 and a detection circuit 75 that implements the detection unit 72.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  DESCRIPTION OF SYMBOLS 1 Wire electric discharge machine, 10 Wire electrode, 20 Wire moving part, 40 Drive part, 50 Tension provision part, 90 Relative position measuring part, 100 Control apparatus, W workpiece.

Claims (4)

A relative position measuring unit for measuring the relative position between the wire electrode and the workpiece;
The relative position measuring unit measures the relative position measurement unit when the wire electrode and the workpiece are in contact with each other, and the position of the wire electrode in contact with the workpiece is made different in the longitudinal direction of the wire electrode. A control device that repeats multiple times;
A drive unit that relatively moves the wire electrode and the workpiece in a direction intersecting the longitudinal direction;
A wire moving section for moving the wire electrode in the longitudinal direction;
A tension applying unit that applies tension to the wire electrode along the longitudinal direction,
The controller is configured to stop the movement of the wire electrode after the wire moving unit moves the wire electrode along the longitudinal direction, and to move the wire electrode and the workpiece closer to each other. And an operation in which the relative position measuring unit measures the relative position at the time of contact, and repeatedly repeating a plurality of times.
And the said control apparatus makes the tension | tensile_strength before and behind the said wire moving part moving the said wire electrode along the said longitudinal direction weaker than the tension | tensile_strength provided when moving the said wire electrode along the said longitudinal direction. A wire electric discharge machine. The wire discharge according to claim 1 , wherein the control device calculates a relative position between the wire electrode and the workpiece based on the relative position at the time of contact measured by the relative position measurement unit a plurality of times. Processing machine. A drive unit for the wire electrode and the word over click to relatively move in a direction crossing the longitudinal direction of the wire electrode, a wire moving portion for moving the wire electrode in the longitudinal direction, and the said wire electrode workpiece A wire electrical discharge machine control device comprising: a relative position measuring unit that measures the relative position of the wire electrode; and a tension applying unit that applies tension to the wire electrode along the longitudinal direction,
An operation for stopping the movement of the wire electrode after the wire moving unit moves the wire electrode along the longitudinal direction, an operation for the driving unit to bring the wire electrode and the workpiece close to each other, and the relative position The measurement unit repeats the operation of measuring the relative position at the time of contact when the wire electrode and the workpiece are in contact with each other multiple times in order, thereby making the relative position at the time of contact different from each other in the longitudinal direction When the wire moving part moves the wire electrode along the longitudinal direction, the tension before and after the wire moving part moves the wire electrode along the longitudinal direction is measured. controller features and to Ruwa ear discharge machine that weaker than the tension imparting electrode when moving along said longitudinal direction. The control apparatus for a wire electric discharge machine according to claim 3 , wherein the relative position between the wire electrode and the workpiece is calculated based on the relative position at the time of contact measured by the relative position measurement unit a plurality of times. .

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