Electric discharge processing electrode wire and quality evaluation method

Abstract

To provide an electric discharge processing electrode wire that can suppress formation of a vertical stripe on a work-piece, and a quality evaluation method.SOLUTION: In an electric discharge processing electrode wire 1, a width W1 of a partial scratch 3 formed partially in a longer direction is 4.0 μm or less. A quality evaluation method evaluates quality of the electric discharge processing electrode wire 1 on the basis of the width W1 of the partial scratch 3 formed partially in the longer direction of the electric discharge processing electrode wire 1.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electrode wire for electric discharge machining and a quality evaluation method. [Background technology]

[0002] Patent Document 1 discloses an electrode wire for electrical discharge machining in which the standard deviation of the diameter at multiple points in the longitudinal direction is 0.15 μm or less. Patent Document 1 also describes that by keeping the standard deviation at 0.15 μm or less, the formation of vertical streaks on a workpiece during electrical discharge machining can be suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-119020 Summary of the Invention [Problem to be solved by the invention]

[0004] It has become clear that the state of scratches formed on the surface of the electrode wire for EDM affects the formation of vertical streaks in the workpiece.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide an electric discharge machining electrode wire and a quality evaluation method that can suppress the formation of vertical streaks in a workpiece. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides an electrode wire for electric discharge machining, in which the width of partial scratches formed partially in the longitudinal direction is 4.0 μm or less.

[0007] In order to achieve the above object, the present invention also provides a quality evaluation method for evaluating the quality of an electric discharge machining electrode wire based on the width of a partial scratch formed partially in the longitudinal direction of the electric discharge machining electrode wire. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an electric discharge machining electrode wire and a quality evaluation method that can suppress the formation of vertical streaks on a workpiece. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 2 is a schematic perspective view of an electric discharge machining electrode wire showing full-length scratches in the embodiment. [Figure 1B] FIG. 10 is a schematic perspective view of an electric discharge machining electrode wire showing parallel partial scratches in the embodiment. [Figure 1C] FIG. 2 is a schematic perspective view of an electric discharge machining electrode wire showing an inclined partial scratch in the embodiment. [Figure 2] 10 is an enlarged view of the periphery of a partial flaw in a schematic cross-sectional view of an electric discharge machining electrode wire perpendicular to the longitudinal direction of the partial flaw in the embodiment; FIG. [Figure 3] 1 is a diagram showing a schematic configuration of a wire drawing machine used to manufacture an electrode wire for electric discharge machining according to an embodiment. [Figure 4] 1 is a diagram showing an outline of an electric discharge machine in which an electric discharge machining electrode wire and a workpiece are set in an embodiment; [Figure 5] FIG. 10 is a perspective view showing the state of the workpiece after machining in an experimental example. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Embodiment Mode] An embodiment of the present invention will be described with reference to Figures 1 to 5. The embodiment described below is shown as a preferred specific example for carrying out the present invention, and although various technically preferable technical matters are specifically exemplified, the technical scope of the present invention is not limited to this specific embodiment.

[0011] (Electrode wire for electrical discharge machining) The electric discharge machining electrode wire is made of a conductive and flexible wire material. The electric discharge machining electrode wire is, for example, a single wire having a circular cross section perpendicular to the longitudinal direction. The electric discharge machining electrode wire may be made of a core material and a coating layer covering the surface of the core material, but the electric discharge machining electrode wire in this embodiment is assumed to be a brass wire without a coating layer. The diameter of the electric discharge machining electrode wire is, for example, 0.02 mm or more and 0.40 mm or less.

[0012] The electrical discharge machining electrode wire of this embodiment is made of brass wire with a zinc content of 30% by mass or more. In particular, the electrical discharge machining electrode wire of this embodiment is made of brass wire with a zinc content of 40% by mass or more (preferably more than 40% by mass). Using a brass wire with a high zinc content (particularly 40% by mass or more) as the electrical discharge machining electrode wire makes it easier for fine discharges (i.e., discharges with low energy) to occur between the electrical discharge machining electrode wire and the workpiece during electrical discharge machining. As a result, the amplitude of the electrical discharge machining electrode wire becomes smaller, and vertical streaks are less likely to form on the workpiece. The electrical discharge machining electrode wire can be, for example, a brass wire with a copper content of 57% by mass and a zinc content of 43% by mass. When the electrical discharge machining electrode wire is made of brass wire without a coating layer, as in this embodiment, the upper limit of the zinc content is preferably 50% by mass, more preferably 43% by mass. If the zinc content of the electrical discharge machining electrode wire is too high, the electrical discharge machining electrode wire becomes brittle, resulting in chipping, breakage, and other problems during wire drawing, making manufacturing difficult.

[0013] For example, the aforementioned Patent Document 1 (i.e., JP 2021-119020 A) discloses an example in which the formation of vertical streaks on the workpiece is suppressed by reducing the dimensional variation of the electrode wire for electric discharge machining so that the standard deviation of the diameter at multiple points in the longitudinal direction is 0.15 μm or less.

[0014] However, even if the zinc content of the electrical discharge machining electrode wire is increased or the dimensional variation of the electrical discharge machining electrode wire is suppressed as described in Patent Document 1, if a large partial flaw (described later) is formed in the electrical discharge machining electrode wire, the energy during electrical discharge machining increases, the amplitude of the electrical discharge machining electrode wire increases, and there is a possibility that vertical streaks will be formed in the workpiece.

[0015] Here, we will explain the scratches that can be unavoidably formed on the electric discharge machining electrode wire. Figures 1A to 1C show three types of scratches that can be formed on the surface of the electric discharge machining electrode wire 1. Note that, for convenience, Figures 1A to 1C show the three types of scratches separately, but these scratches can be formed on the same electric discharge machining electrode wire.

[0016] First, FIG. 1A shows scratches formed on the surface of the electric discharge machining electrode wire 1, which are continuously formed over the entire length of the electric discharge machining electrode wire 1 (hereinafter referred to as "full-length scratches 2"). The full-length scratches 2 are thought to be caused by an abnormality in a wire drawing die (e.g., reference numeral 44 in FIG. 3 described below) used when manufacturing the electric discharge machining electrode wire 1 by wire drawing. Possible abnormalities in the wire drawing die include, for example, adhesion of metal powder mixed in the lubricating oil surrounding the wire drawing die to the inner peripheral surface of the wire drawing die, or deformation caused by metal powder hitting the inner peripheral surface of the wire drawing die. When such an abnormality in the wire drawing die occurs, the full-length scratches 2 are formed in the manufactured electric discharge machining electrode wire 1.

[0017] 1B and 1C show scratches formed on the surface of the electric discharge machining electrode wire 1, which are partially formed in the longitudinal direction of the electric discharge machining electrode wire 1 (hereinafter referred to as "partial scratches 3"). The partial scratches 3 shown in FIG. 1B are scratches along the longitudinal direction of the electric discharge machining electrode wire 1 (hereinafter referred to as "parallel partial scratches 31"), and the scratches shown in FIG. 1C are scratches in a direction inclined with respect to the longitudinal direction of the electric discharge machining electrode wire 1 (hereinafter referred to as "inclined partial scratches 32"). Hereinafter, when there is no particular need to distinguish between the parallel partial scratches 31 and the inclined partial scratches 32, they will simply be referred to as partial scratches 3.

[0018] One cause of the partial damage 3 is thought to be collision or friction between the electric discharge machining electrode wire 1 and a component located downstream of the wire drawing die (e.g., a dancer (see reference numeral 45 in FIG. 3 described later), a capstan (see reference numeral 46 in FIG. 3), or a guide roller (see reference numeral 47 in FIG. 3)) during wire drawing of the electric discharge machining electrode wire 1. For example, if the electric discharge machining electrode wire 1 moves wildly during wire drawing, the collision or friction described above is thought to occur. For example, the inclined partial damage 32 shown in FIG. 1C is thought to be formed obliquely when the electric discharge machining electrode wire 1 collides or rubs against the side of the V-groove when the outer surface of the guide roller during wire drawing has a V-groove. Another cause of the partial damage 3 is thought to be a scratch on the surface of a component located downstream of the wire drawing die, and this scratched portion comes into contact with the electric discharge machining electrode wire 1 during wire drawing.

[0019] FIG. 2 is an enlarged view of the periphery of the partial scratch 3 in a schematic cross-sectional view of the electric discharge machining electrode wire 1 perpendicular to the longitudinal direction of the partial scratch 3. The partial scratch 3 is formed so as to recess the surface of the electric discharge machining electrode wire 1. A raised portion 33 that rises toward the outer periphery of the electric discharge machining electrode wire 1 is formed around the partial scratch 3 in the electric discharge machining electrode wire 1. This is because, as described above, the partial scratch 3 is formed when the electric discharge machining electrode wire 1 is subjected to an external force downstream of the wire drawing die during wire drawing of the electric discharge machining electrode wire 1. On the other hand, the full-length scratch 2 shown in FIG. 1A is generated such that the shape of the inner periphery of the wire drawing die is transferred to the electric discharge machining electrode wire 1 when the electric discharge machining electrode wire 1 passes through the wire drawing die. Therefore, no raised portion is formed around the full-length scratch 2. As described above, scratches formed on the electric discharge machining electrode wire 1 can include the full-length scratch 2, the parallel partial scratch 31, and the inclined partial scratch 32.

[0020] The electric discharge machining electrode wire 1 of this embodiment suppresses the formation of vertical streaks on the workpiece by setting the width W1 of the partial scratches 3 among the scratches formed on the surface to 4.0 μm or less. This value is supported by experimental examples described later, and the assumed mechanism is explained below.

[0021] As described above, raised portions 33 are formed around the partial scratches 3 of the electric discharge machining electrode wire 1. When the raised portions 33 are present, discharges occur starting from the raised portions 33 during electric discharge machining. The greater the amount of protrusion of the raised portions 33, the shorter the discharge distance between the workpiece and the electric discharge machining electrode wire 1 during electric discharge machining. This increases the repulsive force acting on the electric discharge machining electrode wire 1 during discharge, which is thought to cause the electric discharge machining electrode wire 1 to strike the workpiece more forcefully, making it more likely that vertical streaks will form in the workpiece. The amount of protrusion of the raised portions 33 is proportional to the width W1 of the partial scratches 3. Therefore, by reducing the width W1 of the partial scratches 3, the amount of protrusion of the raised portions 33 is reduced, thereby suppressing the formation of vertical streaks in the workpiece.

[0022] From the above mechanism, it is believed that by setting the width W1 of the partial flaw 3 of the electric discharge machining electrode wire 1 to 4.0 μm or less, the formation of vertical streaks in the workpiece can be suppressed.

[0023] From the viewpoint of further suppressing the amount of protrusion of the protuberance 33 around the partial scratch 3, it is preferable that the depth D of the partial scratch 3 is small, as shown in Fig. 2. As an example, the depth D of the partial scratch 3 can be 2.0 µm or less, preferably 1.0 µm or less. The depth D of the partial scratch 3 is the radial length between the surface position 1a of the electric discharge machining electrode wire 1 and the bottom of the partial scratch 3, assuming that the electric discharge machining electrode wire 1 does not have the partial scratch 3.

[0024] (Method of manufacturing the electrode wire 1 for electric discharge machining) Next, an example of a method for manufacturing the electric discharge machining electrode wire 1 will be described with reference to Fig. 3. Fig. 3 is a diagram showing a schematic configuration of a wire drawing machine 4 used in manufacturing the electric discharge machining electrode wire 1 of this embodiment.

[0025] The wire drawing machine 4 draws the brass wire 10, which will be processed into the electric discharge machining electrode wire 1, to a desired diameter by running the brass wire 10 through a wire drawing die 44, thereby forming the electric discharge machining electrode wire 1. The wire drawing machine 4 includes, in order from the upstream side, an unwinding bobbin 41, a guide roller 42, a capstan 43, a wire drawing die 44, a dancer 45, a capstan 46, a guide roller 47, and a winding bobbin 48. Note that the upstream side refers to the side opposite to the running direction of the brass wire 10 during wire drawing, and the downstream side refers to the running direction of the brass wire 10 (i.e., the direction of the arrow in FIG. 3).

[0026] The unwinding bobbin 41 is a bobbin around which the brass wire 10 before wire drawing is wound. The brass wire 10 wound around the unwinding bobbin 41 has a larger outer diameter than the electric discharge machining electrode wire 1 after wire drawing.

[0027] The brass wire 10 drawn out from the unwinding bobbin 41 is hung on the outer peripheral surface of the guide roller 42. The guide rollers 42, 47 change the running direction of the brass wire 10 on the upstream side from the running direction of the brass wire 10 on the downstream side. The brass wire 10 that has passed through the guide roller 42 is wound around a capstan 43.

[0028] The capstan 43 is disposed upstream of the wire drawing die 44, and the brass wire 10 that has passed through the guide roller 42 is wound around the capstan 43 and driven to rotate. As a result, the brass wire 10 is fed from the unwinding bobbin 41 to the wire drawing die 44 side due to the frictional force between the outer circumferential surface of the capstan 43 and the brass wire 10. Note that the configuration of the capstan 43 is not limited to this, and it may be any configuration that is capable of feeding out the brass wire 10.

[0029] The wire drawing die 44 has a hole with a portion whose diameter decreases toward the downstream side. The brass wire 10 fed from the capstan 43 passes through the hole of the wire drawing die 44 and is drawn to a desired outer diameter. Lubricating oil is supplied to the wire drawing die 44 to promote lubrication between the hole and the brass wire 10. The wire drawing die 44 may have multiple wire drawing dies, for example, with the inner diameter of the die on the downstream side becoming smaller. The brass wire 10 fed from the wire drawing die 44 is wound around a dancer 45.

[0030] The dancer 45 has, for example, a fixed roll 451 whose rotation axis is fixed, and a movable roll 452 that is movable in the radial direction of the fixed roll 451 relative to the fixed roll 451. The dancer 45 maintains a constant tension in the brass wire 10 by moving the movable roll 452 in accordance with the tension of the brass wire 10 fed from the wire drawing die 44. The brass wire 10 fed from the dancer 45 is wound around a capstan 46.

[0031] The capstan 46 has a similar configuration to the capstan 43. The capstan 46 feeds the brass wire 10 from the dancer 45 side to the take-up bobbin 48 side. The brass wire 10 fed from the capstan 46 passes through a guide roller 47 to change its running direction, and is then wound onto the take-up bobbin 48. The brass wire 10 wound onto the take-up bobbin 48 is the electrode wire 1 for electric discharge machining.

[0032] The above-described wire drawing machine 4 can be used to manufacture the electric discharge machining electrode wire 1. Note that the configuration of the above-described wire drawing machine 4 is merely an example and an outline, and various other wire drawing machines can be adopted.

[0033] In this embodiment, as described above, it is necessary to manufacture an electric discharge machining electrode wire 1 having a width of the partial flaw 3 of 4.0 μm or less. The width W1 of the partial flaw 3 formed in the manufactured electric discharge machining electrode wire 1 can be controlled, for example, by devising a manufacturing method for the electric discharge machining electrode wire 1.

[0034] For example, by using a wear-resistant material for the members located downstream of the wire drawing die 44, such as the dancer 45, capstan 46, and guide roller 47, the width W1 of the partial damage 3 in the produced electric discharge machining electrode wire 1 can be reduced. As described above, it is thought that scratches on the members located downstream of the wire drawing die 44 (i.e., the dancer 45, capstan 46, guide roller 47, etc.) are one cause of the partial damage 3 in the electric discharge machining electrode wire 1. However, by forming the members located downstream of the wire drawing die 44 from a wear-resistant material, the formation of scratches on these members can be suppressed. As a result, the width W1 of the partial damage 3 in the produced electric discharge machining electrode wire 1 can be reduced.

[0035] Furthermore, if the materials of the components located downstream of the wire drawing die 44, such as the dancer 45, capstan 46, and guide roller 47, are relatively susceptible to wear, the width W1 of the partial flaw 3 in the produced electric discharge machining electrode wire 1 can be reduced by replacing these components relatively early.

[0036] In addition, for example, the width W1 of the partial scratches 3 in the produced electric discharge machining electrode wire 1 can also be reduced by slowing down the feed speed of the electric discharge machining electrode wire 1 during wiredrawing. By slowing down the feed speed of the brass wire 10 during wiredrawing, the electric discharge machining electrode wire 1 is prevented from colliding with and being worn by members located downstream of the wiredrawing die 44 when the electric discharge machining electrode wire 1 moves wildly during wiredrawing, and as a result, the width W1 of the partial scratches 3 in the produced electric discharge machining electrode wire 1 can be reduced. For the same reason, the width W1 of the partial scratches 3 in the produced electric discharge machining electrode wire 1 can also be reduced by weakening the tension of the electric discharge machining electrode wire 1 during wiredrawing.

[0037] The above provides examples of manufacturing conditions that affect the width W1 of the partial scratch 3. However, by appropriately adjusting the manufacturing conditions that affect the width W1 of the partial scratch 3, it is possible to reduce the width W1 of the partial scratch 3 formed in the electric discharge machining electrode wire 1.

[0038] (Quality evaluation method for electric discharge machining electrode wire 1) Next, a method for evaluating the electric discharge machining electrode wire 1 manufactured as described above will be described. In the quality evaluation method for the electric discharge machining electrode wire 1 of this embodiment, the quality of the electric discharge machining electrode wire 1 is evaluated based on the width W1 of the partial flaw 3 of the electric discharge machining electrode wire 1. Specifically, if the width W1 of the partial flaw 3 of the electric discharge machining electrode wire 1 is equal to or less than a predetermined reference value of 4.0 μm, the product is evaluated as passing, and if the width W1 of the partial flaw 3 exceeds the reference value, the product is evaluated as failing. In this embodiment, the reference value is 4.0 μm. If the product passes, it is judged to be usable for electric discharge machining, and if the product fails, it is judged to be unusable for electric discharge machining.

[0039] The width W1 of the partial flaw 3 of the electric discharge machining electrode wire 1 can be measured using, for example, a scanning electron microscope (SEM). The partial flaw 3 is often formed by repeating the same flaw at each cycle of a guide roller or the like during wire drawing. In such cases, by measuring the maximum width W1 of the partial flaw 3 at one location on the electric discharge machining electrode wire 1, it is possible to determine whether the width W1 of the partial flaw 3 of the electric discharge machining electrode wire 1 is 4.0 μm or less. Furthermore, if the electric discharge machining electrode wire 1 has multiple partial flaws 3 with different widths W1, the product can be determined to be acceptable if the maximum width W1 of the multiple partial flaws 3 is 4.0 μm or less.

[0040] (Use of the electric discharge machining electrode wire 1) Next, an example of a usage mode of the electric discharge machining electrode wire 1 of this embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram showing an outline of an electric discharge machine 5 in which the electric discharge machining electrode wire 1 and a workpiece 6 are set.

[0041] The electric discharge machine 5 has a first roller 51 and a second roller 52 over which the electric discharge machining electrode wire 1 is wound. The electric discharge machine 5 is configured so that the electric discharge machining electrode wire 1 can run from the first roller 51 side toward the second roller 52 side. Electric discharge machining is performed on the workpiece 6 at the portion of the electric discharge machining electrode wire 1 between the first roller 51 and the second roller 52.

[0042] The workpiece 6 is fixed to a table (not shown) of the electric discharge machine 5. The table is configured to be movable in a direction perpendicular to the portion of the electric discharge machining electrode wire 1 between the first roller 51 and the second roller 52. During electric discharge machining, the table and workpiece 6 move relative to the electric discharge machining electrode wire 1, and the workpiece 6 is machined into a shape corresponding to the movement trajectory. A through hole called a start hole 60 is formed in the workpiece 6 in advance, and the portion of the electric discharge machining electrode wire 1 between the first roller 51 and the second roller 52 is passed through the start hole 60 and set.

[0043] The electric discharge machine 5 also includes a power supply device 53 for generating an electric discharge between the electric discharge machining electrode wire 1 and the workpiece 6. The power supply device 53 applies a voltage for electric discharge so that the workpiece 6 is positive and the electric discharge machining electrode wire 1 is negative.

[0044] The electric discharge machine 5 then runs the electric discharge machining electrode wire 1 from the first roller 51 side toward the second roller 52 side, generating an electric discharge between the electric discharge machining electrode wire 1 and the workpiece 6, thereby melting the workpiece 6 and cutting it into a desired shape. After passing through the second roller 52, the worn electric discharge machining electrode wire 1 is collected in a predetermined location. Note that the configuration of the electric discharge machine 5 described above is merely an example and an outline, and various other electric discharge machines can be used.

[0045] (Actions and Effects of the Embodiments) In the electric discharge machining electrode wire 1 of this embodiment, the width W1 of the partial flaw 3 is 4.0 μm or less. Therefore, when the electric discharge machining electrode wire 1 of this embodiment is used to electric discharge machine the workpiece 6, the formation of vertical streaks in the workpiece 6 is suppressed.

[0046] Furthermore, the electrical discharge machining electrode wire 1 includes a brass wire with a zinc content of 30% by mass or more (particularly 40% by mass or more). This reduces the amplitude of the electrical discharge machining electrode wire 1 during electrical discharge machining using the electrical discharge machining electrode wire 1, making it more difficult for vertical streaks to form on the workpiece 6.

[0047] Furthermore, the depth of the partial scratches 3 is 2.0 μm or less. Therefore, the amount of protrusion of the protrusion 33 can be reduced, and as a result, the occurrence of vertical streaks on the workpiece 6 can be easily suppressed.

[0048] Furthermore, the quality evaluation method for the electric discharge machining electrode wire 1 of this embodiment evaluates the quality of the electric discharge machining electrode wire 1 based on the width W1 of the partial flaws 3 partially formed in the longitudinal direction of the electric discharge machining electrode wire 1. In this way, by evaluating the quality of the electric discharge machining electrode wire 1 based on the width W1 of the partial flaws 3 among the flaws formed in the electric discharge machining electrode wire 1, it is possible to determine which electric discharge machining electrode wires 1 are less likely to form vertical streaks in the workpiece 6.

[0049] Furthermore, the quality evaluation method for the electric discharge machining electrode wire 1 of this embodiment evaluates the quality of the electric discharge machining electrode wire 1 based on whether the width W1 of the partial flaw 3 is equal to or less than a predetermined reference value of 4.0 μm or less. Therefore, it is easier to determine whether the electric discharge machining electrode wire 1 is less likely to form vertical streaks on the workpiece 6.

[0050] As described above, according to the present embodiment, it is possible to provide an electric discharge machining electrode wire and a quality evaluation method that can suppress the formation of vertical streaks in a workpiece.

[0051] [Experimental Example] This experimental example is an example in which the relationship between the width of the full-length flaw, the width of the parallel portion flaw, and the width of the inclined portion flaw of the electric discharge machining electrode wire and the likelihood of vertical streaks being formed in the workpiece was evaluated.

[0052] In this example, electric discharge machining electrode wires according to Examples 1 and 2 and Comparative Examples 1 to 3 were prepared, each having a different combination of the width of the full-length flaw, the width of the parallel portion flaw, and the width of the inclined portion flaw. In the electric discharge machining electrode wires according to Examples 1 and 2, the width of the parallel portion flaw and the width of the inclined portion flaw are each 4.0 μm or less, and in the electric discharge machining electrode wires according to Comparative Examples 1 to 3, at least one of the width of the parallel portion flaw and the width of the inclined portion flaw exceeds 4.0 μm.

[0053] The electrical discharge machining electrode wires of Examples 1 and 2 and Comparative Examples 1 to 3 are made of brass wires with the same basic configuration as the embodiment. That is, the electrical discharge machining electrode wires of Examples 1 and 2 and Comparative Examples 1 to 3 are all made of brass wires with a circular cross section and a copper content of 57% by mass and a zinc content of 43% by mass, and no coating layer is formed on the surface. In addition, the electrical discharge machining electrode wires of Examples 1 and 2 and Comparative Examples 1 to 3 all have a wire diameter of 0.20 mm.

[0054] Then, using the electric discharge machining electrode wires of Examples 1 and 2 and Comparative Examples 1 to 3, electric discharge machining was performed on workpieces, and the presence or absence of vertical streaks on the workpieces was investigated. The electric discharge machining was performed using a ROBOCUT α-0iE manufactured by FANUC CORPORATION. The number of machining operations was three, and the standard conditions for the first cut to the third cut, which are pre-installed on the ROBOCUT α-0iE, were used. The workpieces were 20 mm thick SKD11 plate materials, which were cut into 10 mm square pieces as shown in Figure 5 using the electric discharge machining electrode wires of Examples 1 and 2 and Comparative Examples 1 to 3. After electric discharge machining, the presence or absence of vertical streaks on the surfaces of the workpieces was visually confirmed. The results are shown in Table 1 below.

[0055] [Table 1]

[0056] As can be seen from Table 1, when electrical discharge machining was performed using the electrical discharge machining electrode wires of Examples 1 and 2, in which the widths of the parallel and inclined partial scratches were each 4.0 μm or less, no vertical streaks were observed in the workpiece. On the other hand, when electrical discharge machining was performed using the electrical discharge machining electrode wires of Comparative Examples 1 to 3, in which the widths of at least one of the parallel and inclined partial scratches exceeded 4.0 μm, vertical streaks were observed in the workpiece. These results demonstrate that the electrical discharge machining electrode wire, with a partial scratch width of 4.0 μm or less, can prevent the formation of vertical streaks in the workpiece. Furthermore, even if relatively large full-length scratches are formed in the electrical discharge machining electrode wire, the formation of vertical streaks in the workpiece can be prevented by limiting the widths of the parallel and inclined partial scratches to 4.0 μm or less.

[0057] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiments will be described by using the reference numerals and the like in the embodiments. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0058] [1] An electric discharge machining electrode wire (1) in which a width (W1) of a partial scratch (3) partially formed in the longitudinal direction is 4.0 μm or less.

[0059] [2] The electric discharge machining electrode wire 1 according to [1], which has a brass wire with a zinc content of 30% by mass or more.

[0060] [3] The electrical discharge machining electrode wire 1 according to [2], wherein the brass wire has a zinc content of 40 mass % or more.

[0061] [4] The electric discharge machining electrode wire 1 according to any one of [1] to [3], wherein the depth D of the partial flaw 3 is 2.0 μm or less.

[0062] [5] A quality evaluation method for evaluating the quality of an electrode wire for electric discharge machining based on a width W1 of a partial scratch 3 formed partially in the longitudinal direction of the electrode wire for electric discharge machining.

[0063] [6] A quality evaluation method according to [5], in which the quality of the electric discharge machining electrode wire 1 is evaluated based on whether the width W1 of the partial flaw 3 is equal to or less than a predetermined standard value of 4.0 μm or less.

[0064] [7] The quality evaluation method according to [6], wherein the electric discharge machining electrode wire 1 comprises a brass wire having a zinc content of 30 mass % or more.

[0065] [8] The quality evaluation method according to [7], wherein the brass wire has a zinc content of 40 mass% or more.

[0066] (Addendum) Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the above-described embodiments. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. Furthermore, the present invention can be appropriately modified and implemented within the scope of its spirit. [Explanation of symbols]

[0067] 1...Electrode wire for electrical discharge machining 3…Partial scratches D: Depth of partial damage W1: Width of partial scratch

Claims

1. The width of the partial scratches partially formed in the longitudinal direction is 4.0 μm or less. Electrode wire for electrical discharge machining.

2. The wire has a zinc content of 30% by mass or more. The electrode wire for electric discharge machining according to claim 1.

3. The brass wire has a zinc content of 40% by mass or more. The electrode wire for electric discharge machining according to claim 2.

4. The depth of the partial scratches is 2.0 μm or less. The electrode wire for electric discharge machining according to claim 1 or 2.

5. evaluating the quality of the electric discharge machining electrode wire based on the width of a partial scratch formed partially in the longitudinal direction of the electric discharge machining electrode wire; Quality assessment methods.

6. evaluating the quality of the electric discharge machining electrode wire based on whether the width of the partial flaw is equal to or less than a predetermined reference value of 4.0 μm or less; The quality evaluation method according to claim 5.

7. The electric discharge machining electrode wire has a brass wire with a zinc content of 30% by mass or more. The quality evaluation method according to claim 6.

8. The brass wire has a zinc content of 40% by mass or more. The quality evaluation method according to claim 7.

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