JP7155868B2 - Electrode wire for wire electric discharge machining - Google Patents

Description

The present invention relates to an electrode wire for wire electric discharge machining.

As one of the machines for machining the contour shape of a conductive workpiece, an intermittent pulse discharge is generated between the electrode wire for wire electric discharge machining and the workpiece, and the thermal action at this time and the 2. Description of the Related Art A wire electric discharge machine is known that performs machining while melting and removing a workpiece by impact force.

Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2007-136579) describes an electrode wire for wire electric discharge machining having a square cross section. Further, Patent Document 2 (Japanese Unexamined Patent Application Publication No. 6-143038) describes that an electrode wire for wire electric discharge machining is twisted in order to improve the speed of wire electric discharge machining.

JP 2007-136579 A JP-A-6-143038

Regarding the wire electric discharge machining technology, there is a general problem to improve the machining speed by electric discharge. In addition, if the consumption of wire electric discharge machining electrode wires can be reduced with respect to the amount of machining by improving the machining speed, the cost required for exchanging the wire electric discharge machining electrode wires can be suppressed, and the machining cost can be reduced. It is possible.

Here, when machining is performed using a wire electric discharge machining electrode wire having a circular cross section, when the wire electric discharge machining electrode wire is brought close to the workpiece, electric discharge occurs only at the closest point. There is a problem that the portion where the workpiece is melted by the electric discharge is limited, resulting in a slow machining speed.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode wire for wire electric discharge machining which can increase the machining speed when electric discharge machining is performed and which is less likely to be worn out.

Other objects and novel features will become apparent from the description and accompanying drawings herein.

A brief outline of representative embodiments among the embodiments disclosed in the present application is as follows.

An electrode wire for wire electric discharge machining according to one embodiment has a cross section orthogonal to an extending direction of a regular polygon having five or more angles, and a plurality of side surfaces orthogonal to the cross It consists of a regular polygonal prism with a flat surface along the existing direction.

According to one embodiment disclosed in the present application, it is possible to provide an electrode wire for wire electric discharge machining that can increase the machining speed when performing electric discharge machining and that is less likely to be worn out.

1 is a schematic perspective view of a wire electric discharge machine including a wire electric discharge machining electrode wire according to a first embodiment of the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of an electrode wire for wire electric discharge machining and a workpiece according to Embodiment 1 of the present invention; FIG. 6 is a cross-sectional view of a wire electric discharge machining electrode wire and a workpiece according to a second embodiment of the present invention; FIG. 6 is a cross-sectional view of a wire electric discharge machining electrode wire and a workpiece according to a second embodiment of the present invention; FIG. 5 is a cross-sectional view of an electrode wire for wire electric discharge machining and a workpiece as a comparative example;

Hereinafter, embodiments will be described in detail based on the drawings. In addition, in all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted. Also, in the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

(Embodiment 1)
The electrode wire for wire electric discharge machining of Embodiment 1 has a regular polygonal cross section (cross-sectional shape), and a regular polygonal prism composed of a plurality of side surfaces perpendicular to the cross section that are flat along the extending direction. As a result, electrical discharge is generated between the electrode wire for wire electrical discharge machining and the workpiece on the surfaces facing each other, thereby reducing wear due to wire electrical discharge and increasing the machining speed.

<Structure of electrode wire for wire electric discharge machining>
The structure of the electrode wire for wire electric discharge machining according to the present embodiment will be described below with reference to FIGS. 1 and 2. FIG. FIG. 1 is a schematic perspective view of a wire electric discharge machine including an electrode wire for wire electric discharge machining according to the first embodiment. FIG. 2 is a sectional view of the electrode wire for wire electric discharge machining according to the first embodiment and a workpiece to be machined by the electrode wire for wire electric discharge machining. The X direction and the Y direction shown in FIGS. 1 and 2 are directions in which the wire electric discharge machining electrode wire can move relative to the workpiece in a plan view. is the direction. The X direction and the Y direction are directions orthogonal to each other in plan view. The Z direction shown in FIGS. 1 and 2 is the extending direction of the electrode wire for wire electric discharge machining, and is the direction perpendicular to the X direction and the Y direction.

As shown in FIG. 1, the wire electric discharge machine has an electrode wire 1 for wire electric discharge machining which is a consumable part and is replaceable, and the electrode wire 1 for wire electric discharge machining is fixed in a stretched state so as to extend in the Z direction. It has rollers 3 and 4 for Although not shown, the wire electric discharge machine has a table around the electrode wire 1 for wire electric discharge machining, which can be moved in the X and Y directions. (Processing object, workpiece, steel material) 2 is fixed. A roller 3 is positioned above the table and the workpiece 2 respectively, and a roller 4 is positioned below the table and the workpiece 2 respectively. In FIG. 1, a start hole 5 is formed penetrating from the upper surface to the lower surface of a plate-shaped workpiece 2, and wire electric discharge is performed to machine a predetermined area from the start hole 5. As shown in FIG. Although not shown, the workpiece 2 is immersed in the working fluid. The working liquid is, for example, a liquid having constant conductivity, and insulating oil, ion-exchanged water, or the like is used.

The wire electric discharge machine generates intermittent pulse electric discharge between the electrode wire 1 for wire electric discharge machining and the workpiece 2, and the workpiece is melted and removed by the thermal action and impact force at this time. is performed. Here, machining is performed by moving the table and the workpiece 2 in the X direction or the Y direction. That is, although it is the workpiece 2 that actually advances, the direction in which the wire electric discharge machining electrode wire 1 advances relative to the workpiece 2 is called the advancing direction (scanning direction) in the present application. The wire electric discharge machining electrode wire 1 is fixed without moving in the X and Y directions, but is sent downward or upward in the Z direction as the rollers 3 and 4 rotate during machining. This is to prevent deterioration of machining accuracy and disconnection due to consumption of the electrode wire 1 for wire electric discharge machining due to electric discharge.

The electrode wire 1 for wire electric discharge machining is made of a conductive material, for example, brass. Moreover, the workpiece 2 is also made of a conductive member. In the wire electric discharge machining, the wire electric discharge machining electrode wire 1 is caused to scan the workpiece 2 while electric discharge is generated between the wire electric discharge machining electrode wire 1 and the workpiece 2 which are both conductive. A workpiece 2 is processed. Since the wire electric discharge machine can process relatively hard materials, it is used for processing, for example, when making molds.

As shown in FIG. 2, a cross section (hereinafter simply referred to as a cross section) of the wire electric discharge machining electrode wire 1, which is a plane orthogonal to the extending direction (Z direction) of the wire electric discharge machining electrode wire 1, is It is a regular polygon. Specifically, the wire electric discharge machining electrode wire 1 has a regular dodecagonal cross section. However, the cross section of the electrode wire 1 for wire electric discharge machining is preferably neither an equilateral triangle nor an equilateral quadrangle, but a regular polygon having five or more angles. The diameter of the wire electric discharge machining electrode wire 1 is, for example, 0.05 to 0.3 mm. In FIG. 2 and FIGS. 3 to 5 used in the following description, hatching is omitted even in cross sections for the sake of clarity. In addition, in FIGS. 2 to 5, one or more arrows indicate locations where discharge occurs. FIG. 2 shows, as an example, the structure during the machining process when the Y direction is the traveling direction of the electrode wire 1 for wire electric discharge machining.

Since the cross section (cross section) of the wire electric discharge machining electrode wire 1 is a regular polygon having a plurality of corners (vertices), the side surface (machined surface) of the machined workpiece 2 has a shape similar to that of the wire electric discharge machining electrode. It has a shape with surfaces facing each of the plurality of side surfaces of the wire 1 . This is because the cross section of the wire electric discharge machining electrode wire 1 is polygonal, so when the wire electric discharge machining electrode wire 1 advances in the Y direction and approaches the workpiece 2, the wire electric discharge machining electrode wire 1 This is because not the corner but the entire side surface of the workpiece 2 comes closest to the workpiece 2 and discharge occurs on the entire side surface.

The main feature of the present embodiment is that by causing the discharge over the entire surface in this way, the discharge generating region is widened and the machining speed is increased. From the viewpoint of obtaining such an effect, it is desirable that one side surface 9 of the wire electric discharge machining electrode wire 1 having a regular polygonal cross section faces the advancing direction (Y direction). In other words, it is desirable that one side surface 9 of the wire electric discharge machining electrode wire 1 having a regular polygonal cross section is perpendicular to the advancing direction (Y direction).

In addition, among the 12 side surfaces of the electrode wire 1 for wire electric discharge machining, two side surfaces 10 at both ends in a direction (X direction) perpendicular to the traveling direction (Y direction) in a plan view are each machined. It is parallel to the side surface of the workpiece 2 . Since the wire electric discharge machining electrode wire 1 has a cross section of a regular polygon having 12 corners, which is a multiple of 4, when one side face 9 faces the traveling direction as described above, Each of the two side surfaces 10 that are perpendicular to each other in plan view, that is, the two side surfaces 10 that are directly lateral to the advancing direction, are always along the advancing direction, and the side surfaces of the machined workpiece 2 are also along the advancing direction. In other words, the side surface 10 is parallel to the traveling direction of the electrode wire 1 for wire electric discharge machining. Therefore, the side surface 10 and the side surface of the processed workpiece 2 are parallel to each other and face each other. Moreover, the cross section of the wire electric discharge machining electrode wire 1 is axisymmetrical, and the two side surfaces 10 are parallel to each other.

For this reason, the side surface 10 of the portion forming the wire electric discharge machining electrode wire 1 traveling in the Y direction, for example, does not come closest to the workpiece 2 . Therefore, electric discharge is less likely to occur between the side surface 10 and the side surface of the workpiece 2, and the electric discharge is generated in the electrode wire 1 for wire electric discharge machining located on the traveling direction side (the side of the workpiece 2 to be machined) relative to the side surface 10. occurs between the surface and the workpiece 2; In other words, electric discharge occurs between the surface of the wire electric discharge machining electrode wire 1 and the workpiece 2 within the range of the angle θ1 from the center of the wire electric discharge machining electrode wire 1 in the cross section toward the direction of travel. The angle θ1 is an angle between lines connecting the center of the wire electric discharge machining electrode wire 1 in the cross section of the two side surfaces 10 and the ends of the two side surfaces 10 in the traveling direction. Therefore, the area where the electrode wire 1 for wire electric discharge machining is consumed is limited to within the range of the angle θ1. The angle θ1 is an obtuse angle smaller than 180 degrees.

Here, the wire electric discharge machining electrode wire 1 is not twisted between the rollers 3 and 4 . That is, each of the 12 side surfaces of the electrode wire 1 for wire electric discharge machining faces only one direction between the rollers 3 and 4 . In other words, each of these side surfaces is configured as a continuously flat surface in the extending direction (Z direction) of the wire electric discharge machining electrode wire 1 .

This is because when the wire electric discharge machining electrode wire 1 is twisted, in the extending direction (the Z direction) of the wire electric discharge machining electrode wire 1, electric discharge is likely to occur and electric discharge is difficult to occur. And it is because there is a possibility that a decrease in processing speed may occur. Therefore, in the present embodiment, the electrode wire 1 for wire electric discharge machining is used, which is formed of a regular polygonal prism having no twists and having all flat sides. That is, when the side surface of the wire electric discharge machining electrode wire 1 at a certain height faces a predetermined direction such as the traveling direction (for example, the Y direction), the side surface of the wire electric discharge machining electrode wire 1 at another height is , point in the same predetermined direction (eg, the Y direction). By stretching the electrode wire 1 for wire electric discharge machining without being twisted in this way, it is possible to prevent a decrease in machining accuracy and machining speed.

Wire electric discharge machining performed using such a wire electric discharge machining electrode wire 1 can produce, for example, a mold, a metal part, or a tool (such as a cutting edge of a drill). Further, the electrode wire 1 for wire electric discharge machining having a regular polygonal cross section as in the present embodiment is drawn through a wire drawing die having a regular polygonal hole, for example, so that the metal wire is formed into a desired shape. It can be manufactured by narrowing down to

<Effects of this embodiment>
The effects of this embodiment will be described below with reference to FIG. FIG. 5 is a cross-sectional view of an electrode wire for wire electric discharge machining and a workpiece as a comparative example.

As shown in FIG. 5, the wire electric discharge machining electrode wire 8 of the comparative example differs from the wire electric discharge machining electrode wire of the present embodiment in that its cross section is circular. That is, the cross-sectional profile of the electrode wire 8 for wire electric discharge machining does not have corners or straight lines. In other words, the side surface of the electrode wire 8 for wire electric discharge machining does not have a flat surface. The cross section of the electrode wire 8 for wire electric discharge machining is, for example, a perfect circle.

Wire electric discharge machining is a technique that enables high-precision machining, but the problem is that the machining speed is slow. Increasing the processing speed also leads to a reduction in processing costs due to a reduction in the time required for processing and a reduction in the amount of wire used.

Electric discharge in wire electric discharge machining occurs when the electrode wire for wire electric discharge machining and the workpiece come close to a certain distance. Therefore, when the wire electric discharge machining electrode wire 8 has a circular cross section as in the comparative example shown in FIG. happens. Since the electrode wire 8 for wire electric discharge machining extends in the Z direction, if the Z direction (height direction) is also taken into account, it can be said that in the comparative example, electric discharge occurs not in points but in lines.

As a result, the melted portion of the workpiece 2 is limited to one point in plan view, and the range that can be machined by one discharge of the intermittent pulse discharge is limited to a narrow range. Therefore, there is a problem that the speed of electric discharge machining of the workpiece 2 is slow.

In the case of the wire electric discharge machining electrode wire 8 having a perfectly circular cross section, the surface of the wire electric discharge machining electrode wire 8 within the range of the angle θ4 that spreads in the direction of travel from the center of the cross section and the workpiece 2 A discharge occurs between The angle θ4 is 180 degrees. This is because the cross section of the wire electric discharge machining electrode wire 8 is a perfect circle, so that the entire area of the semicircle on the advancing direction side of the surface of the wire electric discharge machining electrode wire 8 is closest to the workpiece 2 . This is because there is a possibility that The fact that electric discharge occurs over a wide range of the side surfaces of the wire electric discharge machining electrode wire 8 in this way means that the wire electric discharge machining electrode wire 8 is consumed more by the electric discharge. When the range and amount of wear due to electric discharge are large, the electrode wire 8 for wire electric discharge machining becomes thinner by performing electric discharge, and the possibility of disconnection of the electrode wire 8 for wire electric discharge machining increases.

In order to prevent wire breakage, it is conceivable to increase the replacement speed (the speed of feeding in the Z direction) of the electrode wire 8 for wire electric discharge machining, but this causes an increase in machining costs. In order to prevent wire breakage, it is conceivable to lower the power applied to the workpiece 2 and the electrode wire 8 for wire electric discharge machining. The amount may also decrease, resulting in a decrease in the speed of electrical discharge machining.

On the other hand, in the present embodiment, as shown in FIG. 2, the wire electric discharge machining electrode wire 1 has a regular polygonal cross section. For this reason, in wire electric discharge machining, the wire electric discharge machining electrode wire 1 is brought closest to the workpiece 2 not by one point at a predetermined corner but by the entire one of the 12 side surfaces. That is, electric discharge occurs on the surface of the electrode wire 1 for wire electric discharge machining. At this time, electric discharge occurs simultaneously on each of a plurality of side surfaces with a single application of electric power, so that the surface of the workpiece 2 can be melted over a much wider range than in the comparative example, so the machining speed is dramatically increased. can be increased to Further, even when electric discharge occurs only on one of the plurality of side surfaces of the electrode wire 1 for wire electric discharge machining by applying electric power once, electric discharge occurs at one point or line as in the comparative example. Compared to the case, the amount of melting of the workpiece can be increased, thereby increasing the processing speed.

The above effect can also be obtained when the number of corners of the regular polygon of the cross section of the wire electric discharge machining electrode wire 1 is an odd number, or when the number of corners is an even number other than a multiple of four. In other words, the above effect can be obtained when the cross section of the electrode wire 1 for wire electric discharge machining according to the present embodiment is a regular polygon having five or more corners.

If the number of corners of the cross section of the wire electric discharge machining electrode wire 1 is a multiple of 4 (for example, 12), the wire electric discharge machining electrode wire 1 is arranged with respect to the traveling direction regardless of whether machining is performed in the Y direction or the X direction. The sides of the can be turned, and the corners are not turned in the direction of travel. As a result, it is possible to prevent the machining speed from decreasing as in the comparative example due to the discharge occurring only at one point between the corner and the workpiece 2 . In addition, uneven consumption of the electrode wire 1 for wire electric discharge machining and deterioration of machining accuracy can be prevented. These effects are difficult to obtain when the number of corners of the cross section of the electrode wire 1 for wire electric discharge machining is an odd number compared to when the number of corners is a multiple of four. In addition, when the number of corners is an even number other than a multiple of 4 (for example, a regular hexagon), these effects are obtained when the wire electric discharge machining electrode line 1 is scanned in one direction (for example, the Y direction). can be obtained, it is difficult to obtain when the wire electric discharge machining electrode line 1 is scanned in a direction perpendicular to the direction (for example, the X direction).

Further, when the wire electric discharge machining electrode wire 1 has an odd number of corners in its cross section, the wire electric discharge machining electrode wire 1 is provided between the rollers 3 and 4 so that a desired side surface of the wire electric discharge machining electrode wire 1 faces the workpiece 2 . It is difficult to fix to

Also, the angle θ1 shown in FIG. 2 is smaller than the angle θ4 (180 degrees) shown in FIG. That is, the range in which the electrode wire 1 for wire electric discharge machining is consumed by electric discharge is narrower than in the comparative example. This is because the side surface of the wire electric discharge machining electrode wire 1 and the machined side surface of the workpiece 2 face each other and are parallel to each other in the direction orthogonal to the traveling direction in plan view. . In this way, since the consumption of the electrode wire 1 for wire electric discharge machining can be reduced, it is possible to prevent disconnection caused by thinning of the electrode wire 1 for wire electric discharge machining due to consumption. In addition, since the durability against wire breakage can be improved, the tension of the electrode wire 1 for wire electric discharge machining can be strengthened, and the machining accuracy can be improved. Moreover, since the durability against disconnection can be improved, it is possible to apply a larger electric power to the electrode wire 1 for wire electric discharge machining. Therefore, it is possible to increase the processing speed while preventing disconnection.

The effect of narrowing the range of wear of the electrode wire 1 for wire electric discharge machining as described above is that the number of corners in the cross section of the electrode wire 1 for wire electric discharge machining is an odd number compared to the case where the number of corners is even. Hard to get in some cases. In addition, when the number of corners is an even number other than a multiple of 4 (for example, a regular hexagon), these effects are obtained when the wire electric discharge machining electrode line 1 is scanned in one direction (for example, the Y direction). can be obtained, it is difficult to obtain when the wire electric discharge machining electrode line 1 is scanned in a direction perpendicular to the direction (for example, the X direction).

As described above, the effect of the present embodiment is obtained by making the cross section of the electrode wire 1 for wire electric discharge machining a regular polygon. From the viewpoint of reducing wear of the wire 1, it is desirable that the cross section of the electrode wire 1 for wire electric discharge machining be a regular polygon having angles of multiples of four. In other words, the wire electric discharge machining electrode wire 1 has a first direction (for example, the Y direction) along the cross section of the wire electric discharge machining electrode wire 1 and a second direction (for example, It is desirable to have two planes parallel in each of the X directions).

However, when the wire electric discharge machining electrode wire 1 has a rectangular cross section, the two corners, which are both end portions of the surface of the wire electric discharge machining electrode wire 1 in the advancing direction, are too close to the workpiece 2. The electric discharge concentrates at two places, the machining speed decreases, and the parts of the electrode wire 1 for wire electric discharge machining are worn out unevenly, which may lower the machining accuracy. Further, when the wire electric discharge machining electrode wire 1 has a rectangular cross section, if the work piece 2 is machined in an oblique direction other than the Y direction and the X direction, the places where the electric discharge occurs are limited, and the machining speed and machining accuracy increase. drops sharply. In other words, there is a possibility that the degree of freedom in processing is reduced. These problems also occur when the cross section of the electrode wire 1 for wire electric discharge machining is an equilateral triangle. Therefore, the cross section of the electrode wire 1 for wire electric discharge machining needs to be a regular polygon with more corners than a regular quadrangle. That is, the cross section of the electrode wire 1 for wire electric discharge machining of this embodiment is a regular polygon having five or more corners.

Moreover, it is more desirable that the cross-section of the electrode wire 1 for wire electric discharge machining is a regular polygon having angles that are multiples of four more than four. In this case, if n is an integer larger than 1, the cross section of the electrode wire 1 for wire electric discharge machining is a regular polygon having 4n corners. That is, the cross section of the electrode wire 1 for wire electric discharge machining is a regular polygon having 4n (n>1, n is an integer) corners.

(Embodiment 2)
In the first embodiment, the wire electric discharge machining electrode wire has a regular dodecagon cross section, but the cross section may have a number of corners other than twelve. Here, FIG. 3 shows a wire electric discharge machining electrode wire 6 having a regular hexagonal cross section, and FIG. 4 shows a wire electric discharge machining electrode wire 7 having a regular octagonal cross section.

When the cross section of the wire electric discharge machining electrode wire 1 has a relatively large number of corners like the wire electric discharge machining electrode wire 6 shown in FIG. 3, the cross section of the wire electric discharge machining electrode wire 1 approaches a perfect circle. As a result, it is possible to increase the processing accuracy when processing the workpiece 2 so that the contour thereof has corners or curves. However, as described in the first embodiment using the comparative example, when the cross section of the wire electric discharge machining electrode wire 1 is a perfect circle, the electric discharge occurs at one side of the wire electric discharge machining electrode wire 1 during machining. It is easy to concentrate on a part, the machining speed decreases, and the consumption of the electrode wire 1 for wire electric discharge machining increases. From the viewpoint of preventing such problems from occurring, the number of corners of the regular polygon in the cross section of the wire electric discharge machining electrode wire 1 should not be excessively increased, and is preferably 24 or less. This also applies to the first embodiment. Note that the angle θ2 is larger than the angle θ1 shown in FIG.

When the cross-sectional corners of the wire electric discharge machining electrode wire 1 are relatively small like the wire electric discharge machining electrode wire 7 shown in FIG. It is possible to prevent the problem (decrease in machining speed and increase in wear of the electrode wire 1 for wire electric discharge machining) when the cross section of the electrode wire 1 for electric discharge machining is a perfect circle. In addition, since the corners are small, the discharge area can be increased. Further, since the angle .theta.3 is smaller than the angle .theta.1 shown in FIG. 2, it is possible to narrow the discharge range and suppress wear of the electrode wire 1 for wire electric discharge machining. Therefore, from the viewpoint of increasing the machining speed and suppressing wear of the electrode wire 1 for wire electric discharge machining, it is desirable that the number of corners in the cross section of the electrode wire 1 for wire electric discharge machining is small.

Although the invention made by the present inventors has been specifically described based on the embodiments, the invention is not limited to the above embodiments, and can be variously modified without departing from the gist of the invention. Needless to say.

1, 6 to 8 Wire electric discharge machining electrode wire 2 Workpiece 2
3, 4 Roller 5 Start hole 9, 10 Side

Claims (3)

A cross section orthogonal to the extending direction is a regular polygon having 4n (n>1, n is an integer) and 12 or more and 24 or less angles, and a plurality of side surfaces orthogonal to the cross section An electrode wire for wire electric discharge machining comprising a regular polygonal prism composed of flat surfaces along the extending direction. The electrode wire for wire electric discharge machining according to claim 1 ,
The electrode wire for wire electric discharge machining, wherein the regular polygon has 12 or 16 corners. In the electrode wire for wire electric discharge machining according to claim 1 or 2 ,
The electrode wire for wire electric discharge machining, wherein the plurality of side surfaces have two side surfaces that are parallel to each other, and the two side surfaces are continuously parallel to each other in the extending direction.

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