Wire Electrical Discharge Machine

Abstract

The wire electric discharge machine includes a machining tank, a wire guide that guides a wire electrode into the machining tank, and a guide section that is at least partially immersed in machining fluid stored in the machining tank, and the guide section includes a capacitance adjustment member that adjusts the capacitance between the guide section and the machining tank.

Description

[Technical Field]

[0001] The present disclosure relates to a wire electrical discharge machine. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2010-52092 describes a wire electric discharge machine including an upper guide (upper wire guide) and a lower guide (lower wire guide). A workpiece (object to be machined) is disposed between the upper wire guide and the lower wire guide. The wire electric discharge machine feeds a wire electrode from the upper wire guide toward the lower wire guide. The wire electric discharge machine applies a voltage between the electrodes of the wire electrode and the object to machine the object. Summary of the Invention

[0003] With regard to wire EDM machines, better technology is currently desired.

[0004] One aspect of the present disclosure is a wire electric discharge machine comprising a machining tank, a guide portion including a wire guide for guiding a wire electrode into the machining tank and at least a portion of which is immersed in machining fluid stored in the machining tank, the guide portion comprising a capacitance adjustment member for adjusting the capacitance between the guide portion and the machining tank. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a schematic diagram of a wire electric discharge machine according to one embodiment. [Figure 2] FIG. 2 is a schematic diagram showing a part of a wire electric discharge machine. [Figure 3] FIG. 3 is a schematic diagram showing a part of a wire electric discharge machine. [Figure 4] FIG. 4 is a conceptual diagram showing a virtual bypass capacitor formed inside the machining tank. [Figure 5] FIG. 5 is a diagram schematically illustrating an upper guide portion according to the first modification. [Figure 6]FIG. 6 is a diagram schematically illustrating an upper guide portion according to the first modification. [Figure 7] FIG. 7 is a diagram schematically illustrating an upper guide portion according to the second modification. [Figure 8] FIG. 8 is a diagram schematically illustrating an upper guide portion according to the third modification. DETAILED DESCRIPTION OF THE INVENTION

[0006] The workpiece is subjected to electrical discharge machining while immersed in a machining fluid. The smaller the stray capacitance between the wire electrode and the workpiece, the higher the frequency of the voltage that can be applied between the electrodes. Therefore, in many cases, it is considered preferable to have a smaller stray capacitance in the machining fluid.

[0007] However, when a discharge occurs between the wire electrode and the workpiece, the voltage between the electrodes is unstable. Unstable, random high-frequency voltage is one cause of electrical noise, such as radiated noise and conducted noise. From the perspective of a user (operator, etc.) of a wire electric discharge machine, there are times when it is desirable to perform electric discharge machining while suppressing the generation of electrical noise.

[0008] Based on the above preliminary explanation, one embodiment will be described below. Note that, unless otherwise specified, storage media in the following description are tangible and non-transitory storage media. Furthermore, programs (computer programs, computer software) in the following description are also referred to as computer program products. Computer program products are not limited to programs stored on storage media, but also include programs transmitted, distributed, or downloaded via a network such as the Internet.

[0009] In the following description, the U and V directions are perpendicular to each other. Furthermore, the X and Y directions are perpendicular to each other. The U and X directions may be parallel to each other. The V and Y directions may be parallel to each other. In the following description, the Z direction is perpendicular to the U, V, X, and Y directions. Each of the U, V, X, and Y directions may be parallel to a horizontal plane. The Z direction may coincide with the vertical direction (up and down direction).

[0010] (One embodiment) FIG. 1 is a schematic diagram of a wire electric discharge machine 10 according to one embodiment.

[0011] The wire electric discharge machine 10 is a machine tool that applies a voltage (pulse voltage) between the electrodes of a wire electrode WE and a workpiece WP to perform electric discharge machining on the workpiece WP. The wire electric discharge machine 10 includes a processing machine 12 and a control device 14. The processing machine 12 is a mechanical device that processes the workpiece WP. The control device 14 is an electronic device that controls the processing machine 12. For example, a computer such as a numerical control device is included in the control device 14.

[0012] The processing machine 12 has a lower part 12A and an upper part 12B supported by the lower part 12A. The processing machine 12 also has a plurality of slide mechanisms 16 that are appropriately installed in each of the lower part 12A and the upper part 12B. Each of the plurality of slide mechanisms 16 has, for example, a ball screw 18, a nut 20 that threadably engages with the ball screw 18, a linear rail 22 that extends along the axial direction of the ball screw 18, and a linear block 24. The ball screw 18 is driven to rotate by a drive source 25 such as an electric motor. The drive source 25 may be controlled by the control device 14. The linear block 24 is guided by the linear rail 22 in the extension direction of the linear rail 22 (the axial direction of the ball screw 18).

[0013] The lower portion 12A includes, for example, a bed 26, a Y-axis slider 28 (saddle), an X-axis slider 30 (slide table), a machining tank 32, and a lower arm 40. The bed 26, the Y-axis slider 28, the X-axis slider 30, the machining tank 32, and the lower arm 40 are each formed, for example, by casting. The bed 26 is a base that is placed on an installation surface such as a factory floor. When the wire electric discharge machine 10 is installed on the installation surface, the U direction, V direction, X direction, and Y direction are each parallel to the installation surface. Therefore, when the installation surface is parallel to a horizontal plane, the U direction, V direction, X direction, and Y direction are each horizontal.

[0014] A Y-axis slider 28 is provided on bed 26 via slide mechanism 16Y, one of the multiple slide mechanisms 16. Ball screw 18 (18Y) of slide mechanism 16Y is installed along the Y direction. Nut 20 (20Y) and linear block 24 (24Y) of slide mechanism 16Y are connected to Y-axis slider 28. Linear rail 22 (22Y) of slide mechanism 16Y is provided on bed 26. This allows Y-axis slider 28 to move in the Y direction on bed 26 by slide mechanism 16Y.

[0015] An X-axis slider 30 is provided above the Y-axis slider 28 via a slide mechanism 16X of the multiple slide mechanisms 16. The ball screw 18 (18X) of the slide mechanism 16X is installed along the X direction. A nut 20 (20X) and a linear block 24 (24X) of the slide mechanism 16X are connected to the X-axis slider 30. A linear rail 22 (22X) of the slide mechanism 16X is provided on the Y-axis slider 28. This allows the X-axis slider 30 to move in the X direction on the Y-axis slider 28 by means of the slide mechanism 16X. Note that when the Y-axis slider 28 moves in the Y direction, the X-axis slider 30 provided above the Y-axis slider 28 also moves in the Y direction.

[0016] A machining tank 32 is provided on the X-axis slider 30. When the slide mechanism 16Y or slide mechanism 16X is driven, the machining tank 32 moves together with the X-axis slider 30 in the Y direction or the X direction.

[0017] A machining table 32t that supports the workpiece WP is provided inside the machining tank 32. The machining table 32t and the workpiece WP are immersed in a machining liquid LQ inside the machining tank 32. The machining liquid LQ contains, for example, water, but may also contain oil. The lower arm 40 is located below the upper arm 38 and extends in the Y direction (V direction) from the column 34 to the inside of the machining tank 32. A more detailed description of the lower arm 40 will be given later.

[0018] The upper portion 12B is a portion above the processing tank 32. The upper portion 12B includes, for example, a column 34 (part of the column 34), a head support 35, a head 36, and an upper arm 38. Each of the column 34, the head support 35, the head 36, and the upper arm 38 is formed, for example, by casting.

[0019] The column 34 extends in the Z direction from the bed 26. A portion of the column 34 above the machining tank 32 may be included in the upper portion 12B of the processing machine 12. Note that another portion of the column 34 below this portion may be included in the lower portion 12A of the processing machine 12. A head support 35 is provided above the column 34 via a slide mechanism 16V among the multiple slide mechanisms 16. The ball screw 18 (18V) of the slide mechanism 16V is installed along the V direction. The nut 20 (20V) and linear block 24 (24V) of the slide mechanism 16V are connected to the head support 35. The linear rail 22 (22V) of the slide mechanism 16V is provided on the column 34. This allows the head support 35 to move in the V direction on the column 34 by the slide mechanism 16V.

[0020] The head 36 is provided on the head support 35 via a slide mechanism 16U out of the multiple slide mechanisms 16. The machining tank 32 is located below (directly below) the head 36. The ball screw 18 (18U) of the slide mechanism 16U is installed along the U direction. The nut 20 (20U) and linear block 24 (24U) of the slide mechanism 16U are connected to the head 36. The linear rail 22 (22U) of the slide mechanism 16U is provided on the head support 35. This allows the head 36 to move in the U direction by the slide mechanism 16U. Note that when the head support 35 moves in the V direction, the head 36 provided on the head support 35 also moves in the V direction.

[0021] The head 36 is provided with an upper guide portion 421, which is one of a pair of guide portions 42, via an upper arm 38. The upper guide portion 421 is a guide portion 42 that guides a wire electrode WE supplied from a wire bobbin (not shown) downward (to the machining tank 32). At least a portion of the upper guide portion 421 can be immersed in the machining liquid LQ. The wire bobbin is provided in, for example, the head 36. As the slide mechanism 16U to the slide mechanism 16V are driven, the upper guide portion 421 moves in the U direction or the V direction together with the head 36 (upper arm 38).

[0022] Although not shown in the drawings, the upper arm 38 may be configured to be displaceable in the Z direction. In this case, the processing machine 12 (head 36) may be provided with a slide mechanism 16 that displaces the upper arm 38 in the Z direction.

[0023] The lower arm 40 is located below the upper arm 38. More specifically, the lower arm 40 is located below the processing table 32t and extends from the column 34 to the inside of the processing tank 32 in the Y direction (V direction).

[0024] The lower arm 40 is provided with a lower guide part 422, which is the other of the pair of guide parts 42. The lower guide part 422 is a guide part 42 that collects the wire electrode WE supplied from the upper guide part 421. The entire lower guide part 422 can be immersed in the machining liquid LQ. The workpiece WP (machining table 32t) is located between the upper guide part 421 and the lower guide part 422. The wire electrode WE collected by the lower guide part 422 is sent to a collection box (not shown), for example, through a passage (not shown) that is formed in advance inside the lower arm 40.

[0025] As described above, the machining tank 32 is movable in the X direction or the Y direction. Therefore, the machining table 32t disposed inside the machining tank 32 and the workpiece WP supported by the machining table 32t are movable in the X direction or the Y direction. This allows relative movement between the workpiece WP and the wire electrode WE to be realized.

[0026] As described above, the upper guide portion 421 is movable in the U or V direction together with the upper arm 38. This allows relative movement between the upper guide portion 421 and the lower guide portion 422. When the relative positions of the upper guide portion 421 and the lower guide portion 422 in the U and V directions are the same, the wire electrode WE can extend parallel to the Z direction between the upper guide portion 421 and the lower guide portion 422. When the relative positions of the upper guide portion 421 and the lower guide portion 422 in at least one of the U and V directions are different, the wire electrode WE can be inclined with respect to the vertical axis (Z direction) between the upper guide portion 421 and the lower guide portion 422.

[0027] The processing machine 12 further includes an electric discharge device (not shown). The electric discharge device has a discharge circuit (not shown). The discharge circuit is a circuit that outputs a pulse voltage to the wire electrode WE via the upper guide portion 421 and the lower guide portion 422. The voltage is a pulse voltage for generating an electric discharge between the wire electrode WE and the workpiece WP. The electric discharge generated between the electrodes cuts (consumes) the workpiece WP. The processing table 32t (workpiece WP) may be earthed. The electric discharge device may be controlled by the control device 14.

[0028] 2 and 3 are each a schematic diagram showing a part of the wire electric discharge machine 10. As shown in FIG.

[0029] Each of the pair of guide portions 42 includes a wire guide 44. The wire guide 44 includes an exterior body 46 and an electrode pin, a die guide, and the like (not shown) disposed inside the exterior body 46. A wire insertion hole 46h is formed in advance in the exterior body 46. The exterior body 46 is made of, for example, a casting and is conductive. A wire electrode WE is inserted into the wire insertion hole 46h. The electrode pin contacts the wire electrode WE passing through the wire insertion hole 46h. The discharge device described above is connected to the electrode pin via wiring members and the like (not shown) and applies a voltage to the wire electrode WE via the electrode pin. The die guide is disposed in the wire insertion hole 46h. The die guide holds the wire electrode WE slidably, thereby suppressing misalignment of the wire electrode WE in a direction intersecting the extension direction (Z direction) of the wire insertion hole 46h.

[0030] The upper guide portion 421 further includes a capacitance adjusting member 48. The capacitance adjusting member 48 is a member (or a group of members) for adjusting the capacitance between the upper guide portion 421 and the processing tank 32. That is, the capacitance adjusting member 48 is a member (or a group of members) for adjusting the stray capacitance between the upper guide portion 421 and the processing tank 32. The capacitance adjusting member 48 has one or more conductive members 48a that can be attached to the exterior body 46 of the wire guide 44 included in the upper guide portion 421. The one or more conductive members 48a may be detachable from the exterior body 46. The one or more conductive members 48a may include sheet metal.

[0031] The capacitance adjusting member 48 can be set to a first state and a second state. The first state and the second state have different immersion areas, which are areas of the capacitance adjusting member 48 that are immersed in the machining fluid LQ when the machining fluid LQ in the machining tank 32 is stored up to a predetermined water level.

[0032] More specifically, the capacitance adjustment member 48 is supported by a shaft 50 provided on a side 46s of the exterior body 46 of the wire guide 44 included in the upper guide portion 421. The exterior body 46 of the wire guide 44 included in the upper guide portion 421 and the capacitance adjustment member 48 are at the same potential with respect to the reference potential of the processing machine 12. The shaft 50 may include, for example, a hinge, but is not limited to this. The immersion area changes as the capacitance adjustment member 48 rotates around the shaft 50. For example, the capacitance adjustment member 48 shown in FIG. 2 is in a first state. The capacitance adjustment member 48 shown in FIG. 3 is in a second state. The immersion area in FIG. 2 is smaller than the immersion area in FIG. 3. Note that, in the examples shown in FIGS. 1 to 3, the shaft 50 is provided on the side 46s of the exterior body 46 in the X direction, but the configuration of the upper guide portion 421 is not limited thereto. For example, the shaft 50 may be provided on the side 46s of the exterior body 46 in the Y direction. A shaft 50 (capacitance adjusting member 48) may be provided on each of the Y-direction side portion 46s of the upper guide portion 421 and the X-direction side portion 46s of the upper guide portion 421. The side portion 46s on which the shaft 50 (capacitance adjusting member 48) is provided is preferably selected so that the capacitance adjusting member 48 does not interfere with other members that may be disposed around the upper guide portion 421. For example, if the wiring member connecting the discharge device and the electrode pin described above is wired on the Y-direction side of the upper guide portion 421, the shaft 50 (capacitance adjusting member 48) is preferably provided on the X-direction side portion 46s of the upper guide portion 421.

[0033] The wire electric discharge machine 10 described above provides the following advantageous effects, for example.

[0034] The larger the surface area of ​​the upper guide portion 421 as a conductor, the greater the stray capacitance between the upper guide portion 421 and the machining tank 32. In particular, the relative dielectric constant of the machining fluid LQ is often higher than the relative dielectric constant of air. Therefore, the larger the area of ​​the upper guide portion 421 immersed in the machining fluid LQ, the more significantly the stray capacitance between the upper guide portion 421 and the machining tank 32 tends to increase. In light of this, the capacitance adjustment member 48 expands the surface area of ​​the upper guide portion 421 as a conductor. The capacitance adjustment member 48 changes the immersion area, which can change the stray capacitance between the upper guide portion 421 and the machining tank 32.

[0035] For example, when electric discharge machining is performed under machining conditions in which a relatively high-frequency voltage is applied between the workpieces, the user of the wire electric discharge machine 10 operates the capacitance adjustment member 48 to set the capacitance adjustment member 48 to the first state ( FIG. 2 ). This allows the user to reduce stray capacitance between the upper guide portion 421 and the machining tank 32. As a result, the machine 12 can perform electric discharge machining by applying a relatively high-frequency voltage between the workpieces.

[0036] FIG. 4 is a conceptual diagram showing a virtual bypass capacitor 52 formed inside the processing tank 32. As shown in FIG.

[0037] The user may operate the capacitance adjustment member 48 to set the capacitance adjustment member 48 to the second state (FIGS. 3 and 4). This increases the stray capacitance between the upper guide portion 421 and the machining tank 32 compared to when the capacitance adjustment member 48 is in the first state. This stray capacitance acts as a bypass capacitor 52 within the machining tank 32 (machining fluid LQ). As the stray capacitance functioning as the bypass capacitor 52 increases, the voltage between the electrodes is stabilized, and the generation of electrical noise is suppressed.

[0038] The upper guide portion 421 may include a plurality of conductive members 48a. In this case, the plurality of conductive members 48a may be rotatably supported by a plurality of shaft portions 50 corresponding to the plurality of conductive members 48a. This allows the user to more precisely adjust the stray capacitance between the upper guide portion 421 and the processing tank 32 by appropriately operating at least one of the plurality of conductive members 48a.

[0039] The capacitance adjusting member 48 may be detachable from the upper guide portion 421. This allows the user to more precisely adjust the stray capacitance between the upper guide portion 421 and the processing tank 32 by appropriately changing the shape, area, etc. of the capacitance adjusting member 48.

[0040] The embodiment may be modified as described below. Note that in the following description, explanations that overlap with the embodiment will be omitted as appropriate.

[0041] (Variation 1) 5 and 6 are diagrams each showing a schematic view of an upper guide portion 421 (upper guide portion 421A) according to Modification 1. As shown in FIG.

[0042] The upper guide portion 421A includes a wire guide 44, a capacitance adjusting member 48 (conductive member 48a), and an insulating member 54. When the machining fluid LQ in the machining tank 32 reaches a predetermined water level, the conductive member 48a is immersed in the machining fluid LQ. The wire guide 44 and the conductive member 48a are separated from each other. The insulating member 54 is interposed between the wire guide 44 and the conductive member 48a, connecting the wire guide 44 and the conductive member 48a. In this case, the conductive member 48a separated from the wire guide 44 is connected to the wire guide 44 via the insulating member 54.

[0043] The upper guide portion 421A further includes a switching member 56 and an actuator 58. The switching member 56 is a conductive member that contacts a side portion 46s of the wire guide 44 included in the upper guide portion 421A. For example, the switching member 56 includes a movable electrode (connection electrode). The actuator 58 displaces the switching member 56 to switch the conductive member 48a between a first state and a second state. For example, the actuator 58 includes a cylinder device, a solenoid, or the like. The operation of the actuator 58 may be controlled by the control device 14. In addition, the side portion 46s of the wire guide 44 may be provided with a rail structure (not shown) that slides the switching member 56 in the displacement direction (Z direction, etc.) of the switching member 56.

[0044] The first and second states of this modification differ in the state of conduction between the conductive member 48a and the exterior body 46 of the wire guide 44 included in the upper guide portion 421A. For example, in the first state of this modification, as shown in Fig. 5, the wire guide 44 and the conductive member 48a are separated from each other and are coupled via the insulating member 54 but are not electrically connected (non-conductive state). In this case, the area of ​​the portion of the conductive member 48a that is electrically connected to the exterior body 46 is zero.

[0045] In contrast, in the second state of this modification, as shown in FIG. 6, the switching member 56 contacts the wire guide 44 and the conductive member 48a. This electrically connects (conducts) the wire guide 44 and the conductive member 48a via the switching member 56. In this case, the area of ​​the portion of the conductive member 48a that is electrically connected to the outer casing 46 is greater than zero. The conductive member 48a that is electrically connected to the outer casing 46 and the outer casing 46 are at the same potential. As a result, the effective area of ​​the upper guide portion 421A as a conductor is expanded by the conductive member 48a. Therefore, compared to the case of FIG. 5, the stray capacitance between the upper guide portion 421A and the processing tank 32 increases.

[0046] (Variation 2) FIG. 7 is a diagram schematically showing an upper guide portion 421 (upper guide portion 421B) according to the second modification.

[0047] The capacitance adjusting member 48 may be screwed to the exterior body 46. In the example shown in Fig. 7, the capacitance adjusting member 48 (conductive member 48a) is fixed to the side portion 46s of the exterior body 46 by a screw member 60. According to this modification, the stray capacitance between the upper guide portion 421B and the processing tank 32 changes depending on whether the conductive member 48a is attached to the side portion 46s.

[0048] This modification may be applied to the lower guide portion 422 (see one embodiment). That is, the capacitance adjusting member 48 may be provided not only on the upper guide portion 421B but also on the lower guide portion 422.

[0049] (Variation 3) FIG. 8 is a diagram schematically showing an upper guide portion 421 (upper guide portion 421C) according to the third modification.

[0050] The upper guide portion 421C includes a pressing member 62. The pressing member 62 is a member that presses the capacitance adjusting member 48 (conductive member 48a) against the exterior body 46. The stray capacitance between the upper guide portion 421C and the processing tank 32 changes depending on whether the conductive member 48a contacts the exterior body 46. The pressing member 62 presses down the conductive member 48a, which is disposed on, for example, a stepped portion 64 of the exterior body 46. In this case, the conductive member 48a can be clamped between the pressing member 62 and an edge portion 64e of the stepped portion 64. The pressing member 62 includes, for example, a rubber member such as a rubber cover having a cylindrical shape that is approximately concentric with the wire insertion hole 46h, but is not limited to this.

[0051] The pressing member 62 may be detachable from the exterior body 46 of the upper guide portion 421C. In this case, the conductive member 48a is also detachable from the exterior body 46.

[0052] Similar to the second modification, this modification may also be applied to the lower guide portion 422 (see one embodiment). That is, the capacitance adjusting member 48 and the pressing member 62 may be provided not only in the upper guide portion 421C but also in the lower guide portion 422.

[0053] (Combination of multiple modifications) The above-described multiple modifications may be combined as appropriate as long as they are not inconsistent.

[0054] According to the above-described embodiment and modified examples, the wire electric discharge machine 10 can change the stray capacitance between the guide portion 42 and the machining tank 32 .

[0055] The following additional notes are disclosed regarding the above-described embodiment and modifications.

[0056] (Appendix 1) The wire electric discharge machine (10) according to the present disclosure includes a machining tank (32), a wire guide (44) that guides a wire electrode (WE) into the machining tank, and a guide portion (42) that is at least partially immersed in a machining liquid (LQ) stored in the machining tank, and the guide portion includes a capacitance adjustment member (48) that adjusts the capacitance between the guide portion and the machining tank.

[0057] (Appendix 2) The wire electric discharge machine described in Appendix 1 may be a wire electric discharge machine in which the capacitance adjustment member can be set to a first state and a second state, and the area of ​​the capacitance adjustment member immersed in the machining fluid when the machining fluid is stored to a predetermined water level differs between the first state and the second state.

[0058] (Appendix 3) The wire electric discharge machine may be the one described in Appendix 2, in which the first state and the second state are switched by rotating the capacitance adjustment member around a shaft portion (50) provided on the side portion (46s) of the wire guide.

[0059] (Appendix 4) The wire electric discharge machine described in Appendix 1 may be a wire electric discharge machine in which the capacitance adjustment member can be set to a first state and a second state, and the electrical conduction state between the capacitance adjustment member and the wire guide differs between the first state and the second state.

[0060] (Appendix 5) The wire electric discharge machine described in Appendix 4 may be a wire electric discharge machine in which the first state and the second state are switched by a switching member (56) for switching the connection state between the capacitance adjustment member and the wire guide.

[0061] (Appendix 6) The wire electric discharge machine described in Appendix 5 may be a wire electric discharge machine in which the switching member has a connection electrode for connecting the capacitance adjustment member and the wire guide, and further includes an actuator (58) for displacing the connection electrode.

[0062] (Appendix 7) The wire electric discharge machine according to Supplementary Note 1 may be a wire electric discharge machine in which the capacitance adjustment member is detachable from the wire guide.

[0063] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0064] 10: Wire EDM machine 32: Machining tank 42: Guide part 44: Wire guide 46s: Side portion 48: Capacitance adjusting member 50: Shaft portion 56: Switching member 58: Actuator LQ: Machining fluid WE: Wire electrode

Claims

1. A processing tank; a guide portion including a wire guide for guiding a wire electrode into the machining tank, and at least a portion of the guide portion being immersed in the machining fluid stored in the machining tank; Equipped with The guide portion includes a capacitance adjusting member for adjusting a capacitance between the guide portion and the machining tank.

2. 2. The wire electric discharge machine according to claim 1, the capacitance adjusting member is settable between a first state and a second state; a first state and a second state, the area of ​​the capacitance adjusting member immersed in the machining fluid when the machining fluid is stored up to a predetermined level;

3. 3. The wire electric discharge machine according to claim 2, The wire electric discharge machine is configured such that the first state and the second state are switched by rotating the capacitance adjustment member around a shaft portion provided on a side portion of the wire guide.

4. 2. The wire electric discharge machine according to claim 1, the capacitance adjusting member is settable between a first state and a second state; The wire electric discharge machine, wherein the conduction state between the capacitance adjusting member and the wire guide differs between the first state and the second state.

5. 5. The wire electric discharge machine according to claim 4, The wire electric discharge machine is configured such that the first state and the second state are switched by a switching member that switches the connection state between the capacitance adjusting member and the wire guide.

6. 6. The wire electric discharge machine according to claim 5, the switching member has a connection electrode for connecting the capacitance adjusting member and the wire guide, The wire electric discharge machine further comprises an actuator that displaces the connection electrode.

7. 2. The wire electric discharge machine according to claim 1, The capacitance adjusting member is detachably attached to the wire guide.

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