TWI880835B - Upper/lower auxiliary guides and upper/lower wire guides of wire discharge processing machines - Google Patents

Abstract

The present invention provides an upper auxiliary guide, an upper wire guide, a lower auxiliary guide, and a lower wire guide of a wire discharge processing machine that can stably hold a wire electrode and suppress vibration or positional deviation. An upper auxiliary guide is provided, comprising: a holding portion having a larger aperture than the aperture of an upper main guide; an introduction wall surface that gradually narrows toward the holding portion; and an outlet wall surface that gradually widens from the holding portion, wherein a cross-section of at least a portion of the introduction wall surface has a polygonal shape or a shape obtained by bending each side of the polygonal shape inwardly into an arc shape. Alternatively, a lower auxiliary guide is provided, comprising: a retaining portion having a hole diameter larger than that of the lower main guide; an inlet wall surface gradually narrowing toward the retaining portion; and an outlet wall surface gradually widening from the retaining portion, wherein a cross-section of at least a portion of the outlet wall surface has: a polygonal shape or a shape obtained by bending each side of the polygonal shape inwardly into an arc shape.

Description

Upper/lower auxiliary guides and upper/lower wire guides of wire discharge processing machines

The present invention relates to an upper auxiliary guide used in a wire discharge machining machine and an upper wire guide including the upper auxiliary guide, and a lower auxiliary guide and a lower wire guide including the lower auxiliary guide.

When using a wire discharge machining machine to perform discharge machining, first, a wire electrode is inserted into a pair of wire guides that are set to sandwich the workpiece, and the wire electrode is set up. This operation is called wire connection. The wire guide is also called an eye mask. The wire guide guides and positions the wire electrode that is gradually fed out and moving. Voltage is supplied to the set wire electrode through a power supply assembly.

Hereinafter, based on the workpiece, the wire guide located on the upstream side of the moving direction of the wire electrode is referred to as the upper wire guide, and the guide located on the downstream side of the moving direction of the wire electrode is referred to as the lower wire guide. In addition, among the wire guides, the component that directly holds the wire electrode is referred to as the guide body. Generally, the guide body is made of an insulator with excellent wear resistance such as diamond or sapphire.

Here, as disclosed in Japanese Patent Publication No. 2007-283423, it is known that the through hole of the guide body is composed of the following parts: a holding part having a hole diameter slightly larger than the diameter of the lead electrode; an introduction wall surface of a generally inverted cone shape, which gradually narrows from the introduction side of the lead electrode toward the holding part; and an outlet wall surface of a generally conical shape, which gradually widens from the holding part toward the outlet side of the lead electrode. Since the cross-sections of the introduction wall surface and the outlet wall surface in the past are both circular, the lead electrode is supported at one point on a certain cross-section of the introduction wall surface, and is supported at one point on a certain cross-section of the outlet wall surface.

In addition, as disclosed in Japanese Patent Publication No. 03-234421, two guide main bodies may be provided on the upper wire guide and the lower wire guide, respectively. The lead electrode can be more stably held by guiding the lead electrode using a main guide having a hole diameter slightly larger than the diameter of the lead electrode and a secondary guide having a hole diameter larger than the main guide.

[Problem to be solved by the invention] In order to improve the stability of the holding of the wire electrode and realize high-precision processing, it is possible to consider reducing the hole diameter of the guide body. However, the wire electrode becomes difficult to insert, which makes it easy to fail the connection, and there is also a disadvantage that the wire is easy to break due to the increase in the contact area with the wire electrode. Therefore, there is a limit to the reduction of the diameter of the guide body.

The present invention is made in view of the above situation, and its purpose is to provide an auxiliary guide that can stably hold the wire electrode and suppress vibration or positional deviation without causing a significant adverse effect on the wire connection rate or wire disconnection rate.

[Technical means for solving the problem] According to the present invention, an upper auxiliary guide is provided, which is located on the upstream side of the travel direction of the wire electrode in a wire discharge processing machine relative to the workpiece, and guides the wire electrode together with the upper main guide, wherein the upper auxiliary guide comprises: a holding portion having a larger aperture than the aperture of the upper main guide; an introduction wall surface gradually narrowing from the introduction side of the wire electrode toward the holding portion; and an outlet wall surface gradually widening from the holding portion toward the outlet side of the wire electrode, wherein the cross section of at least a portion of the introduction wall surface has: a polygonal shape or a shape obtained by bending each side of the polygonal shape inwardly into an arc shape.

In addition, according to the present invention, a lower auxiliary guide is provided, which is located on the downstream side of the travel direction of the wire electrode closer to the workpiece in the wire discharge processing machine, and guides the wire electrode together with the lower main guide, and the lower auxiliary guide includes: a holding portion, which has a hole diameter larger than the hole diameter of the lower main guide; an introduction wall surface, which gradually narrows from the introduction side of the wire electrode toward the holding portion; and an outlet wall surface, which gradually widens from the holding portion toward the outlet side of the wire electrode, wherein the cross-section of at least a portion of the outlet wall surface has: a polygonal shape or a shape obtained by bending each side of the polygonal shape inward into an arc shape.

[Effect of the invention] According to the upper sub-guide of the present invention, the wire electrode is guided along two surfaces of a polygonal shape of the introduction wall or a shape obtained by bending each side of the polygonal shape inwardly into an arc shape. That is, the wire electrode is supported at two points on a certain section of the introduction wall of the upper sub-guide. In addition, according to the lower sub-guide of the present invention, the wire electrode is guided along two surfaces of a polygonal shape of the lead-out wall or a shape obtained by bending each side of the polygonal shape inwardly into an arc shape. That is, the wire electrode is supported at two points on a certain section of the lead-out wall of the lower sub-guide. As a result, the wire electrode is stably held, thereby suppressing the occurrence of vibration or positional deviation. Furthermore, higher precision processing can be achieved.

The following is a description of the embodiments of the present invention using the accompanying drawings. The various modifications described below can be implemented in any combination.

Fig. 1 and Fig. 2 show an upper guide unit 1 and a lower guide unit 2 of a wire discharge machining machine of the present embodiment. A workpiece W is provided between the upper guide unit 1 and the lower guide unit 2, and a voltage having a polarity opposite to that applied to the wire electrode E is applied to the workpiece W. The workpiece W is discharge-machined into a desired shape by moving the wire electrode E mounted between the upper guide unit 1 and the lower guide unit 2 relative to the workpiece W. During the discharge machining process, a machining fluid is supplied to a machining gap, which is a tiny gap between the wire electrode E and the workpiece W. The machining fluid is a dielectric fluid having pure water or oil as a main component.

The upper guide unit 1 includes a housing 11, a power-on assembly 13, an upper wire guide 3, and a jet nozzle 15. The housing 11 accommodates the power-on assembly 13 and the upper wire guide 3. In addition, the jet nozzle 15 is mounted on the lower surface of the housing 11. The power-on assembly 13 contacts the wire electrode E at the upstream side of the upper wire guide 3, and a voltage is applied to the wire electrode through the power-on assembly 13. Since the power-on assembly 13 presses the wire electrode E, the wire electrode E at the upstream side of the upper wire guide 3 is tilted. The power supply assembly 13 is configured to be able to move forward and backward, retreating during wiring so as not to hinder the travel path of the wire electrode E, and advancing after the wiring is completed to contact the wire electrode E. The upper wire guide 3 guides the inserted wire electrode E and positions it at the same time. The jet nozzle 15 sprays machining fluid into the machining gap during discharge machining. In addition, the jet nozzle 15 guides the wire electrode E by spraying machining fluid downward during wiring.

The lower guide unit 2 includes: a housing 21, a jet nozzle 25, a lower wire guide 4, and a power-on assembly 23. The housing 21 accommodates the lower wire guide 4 and the power-on assembly 23. In addition, a jet nozzle 25 is mounted on the upper surface of the housing 21. The jet nozzle 25 sprays machining fluid into the machining gap during discharge machining. The lower wire guide 4 guides and positions the inserted wire electrode E. The power-on assembly 23 contacts the wire electrode E at a more downstream side than the lower wire guide 4, and applies voltage to the wire electrode through the power-on assembly 23. Since the power supply assembly 23 presses the wire electrode E, the wire electrode E at the downstream side of the lower wire guide 4 is tilted. The power supply assembly 23 is configured to be movable forward and backward, retreating during wiring so as not to hinder the travel path of the wire electrode E, and advancing to contact the wire electrode E after wiring is completed.

As shown in FIG3 and FIG4, the upper wire guide 3 includes: an upper guide fixture 31, an upper auxiliary guide 33, and an upper main guide 35. The upper guide fixture 31 accommodates the upper auxiliary guide 33 via a support member 337, and accommodates the upper main guide 35 via a support member 357. The upper auxiliary guide 33 and the upper main guide 35 are guide bodies that directly hold the wire electrode E, and include an insulator with excellent wear resistance such as diamond or sapphire. The support members 337 and 357 include an insulator such as ceramic.

As shown in FIG3 and FIG4, the lower wire guide 4 includes: a lower guide fixture 41, a lower main guide 43 and a lower auxiliary guide 45. The lower guide fixture 41 accommodates the lower main guide 43 via a support member 437, and accommodates the lower auxiliary guide 45 via a support member 457. The lower main guide 43 and the lower auxiliary guide 45 are guide bodies that directly hold the wire electrode E, and include an insulator with excellent wear resistance such as diamond or sapphire. The support members 437 and 457 include an insulator such as ceramic.

The upper guide fixture 31 may also include: a side hole 311 for supplying a machining fluid between the upper auxiliary guide 33 and the upper main guide 35. In addition, the lower guide fixture 41 may also include: a side hole 413 for supplying a machining fluid between the lower main guide 43 and the lower auxiliary guide 45. Since the wire electrode E slides relative to the upper wire guide 3 and the lower wire guide 4, a wire powder with a scraped surface may be produced. By supplying machining fluid to the side hole 311, the wire powder accumulated inside the upper wire guide 3 can be discharged from the side of the upper auxiliary guide 33. In addition, by supplying machining fluid to the side hole 413, the wire powder accumulated inside the lower wire guide 4 can be discharged from the side of the lower auxiliary guide 45. The working fluid may be always supplied to the side holes 311 and 413 during the discharge machining.

As shown in FIG. 2 and FIG. 4 , starting from the upstream side of the moving direction of the wire electrode E, the power-on assembly 13, the upper auxiliary guide 33, the upper main guide 35, the workpiece W, the lower main guide 43, the lower auxiliary guide 45, and the power-on assembly 23 are arranged in this order. The upper auxiliary guide 33 and the upper main guide 35 are located on the upstream side of the moving direction of the wire electrode E more than the workpiece W, and guide the wire electrode E. The lower main guide 43 and the lower auxiliary guide 45 are located on the downstream side of the moving direction of the wire electrode E more than the workpiece W, and guide the wire electrode E.

The guide member holder for accommodating the main guide member and the guide member holder for accommodating the auxiliary guide member may be formed integrally or separately. In the present embodiment, the upper auxiliary guide member 33 and the upper main guide member 35 are accommodated in the upper guide member holder 31 formed integrally. The lower main guide member 43 and the lower auxiliary guide member 45 are accommodated in the first lower guide member holder 411 and the second lower guide member holder 412, respectively, and the first lower guide member holder 411 and the second lower guide member holder 412 constitute the lower guide member holder 41. As shown in FIG5, the first lower guide member holder 411 and the second lower guide member holder 412 can be separated. Of course, the upper auxiliary guide 33 and the upper main guide 35 may be housed in different guide fixtures respectively, or the lower main guide 43 and the lower auxiliary guide 45 may be housed in an integrally formed guide fixture.

Although not shown in the figure, for the convenience of loading and unloading, a part of the upper guide member fixture 31 and the lower guide member fixture 41 may be threaded. An outer thread that is threadedly engaged with the housing 11 of the upper guide unit 1 may be formed on the upper portion of the upper guide member fixture 31. An inner thread and an outer thread that are threadedly engaged with each other may be formed on the inside of the first lower guide member fixture 411 and the upper portion of the second lower guide member fixture 412, respectively. An outer thread that is threadedly engaged with the housing 21 of the lower guide unit 2 may be formed on the lower portion of the second lower guide member fixture 412.

The structures of the upper sub-guide 33, the upper main guide 35, the lower main guide 43 and the lower sub-guide 45 as the guide body are described in detail below. In addition, in this specification, unless otherwise specified, the cross section of the guide body refers to: a cross section perpendicular to the insertion direction of the wire electrode E, in other words, it refers to: a cross section perpendicular to the center line of the through hole for the wire electrode E to be inserted.

As shown in Figures 6 and 7, the upper auxiliary guide 33 has: a retaining portion 331, an introduction wall 333 and an outlet wall 335, wherein the retaining portion 331, the introduction wall 333 and the outlet wall 335 constitute a through hole. The retaining portion 331 has a hole diameter larger than the hole diameter of the upper main guide 35. The hole diameter of the retaining portion 331 only needs to be larger than the hole diameter of the upper main guide 35, for example, about 0.4 mm. The introduction wall 333 has a shape that gradually narrows from the introduction side of the wire electrode E toward the retaining portion 331. The outlet wall 335 has a roughly conical shape that gradually expands from the retaining portion 331 toward the outlet side of the wire electrode E. The outlet wall 335 has a circular cross-section.

As shown in FIG8 , the cross-section of at least a portion of the introduction wall 333 has a polygonal shape. The polygonal shape is preferably a regular polygon. In addition, if there are too few vertices, the upper auxiliary guide 33 will be large. If there are too many vertices, the internal angle becomes large, and therefore, the wire electrode E is easily offset. Therefore, the polygonal shape is particularly preferably any one of a regular hexagon, a regular heptagon, a regular octagon, a regular pentagon, and a regular decagon. According to the upper auxiliary guide 33 of this embodiment, the wire electrode E that is tilted by the power-on component 13 is guided along the two faces of the polygonal shape of the introduction wall 333, and therefore, the wire electrode E is stably maintained.

As shown in FIG9 , the upper main guide 35 has: a holding portion 351, an introduction wall surface 353, and an outlet wall surface 355, wherein the holding portion 351, the introduction wall surface 353, and the outlet wall surface 355 constitute a through hole. The holding portion 351 has a hole diameter slightly larger than the diameter of the wire electrode E. The hole diameter of the holding portion 351 is larger than the diameter of the wire electrode E, for example, in a range of about 5 μm or more and about 20 μm or less. According to the diameter of the wire electrode E, an upper wire guide 3 of an appropriate hole diameter is used. The introduction wall surface 353 has a generally inverted cone shape that gradually narrows from the introduction side of the wire electrode E toward the holding portion 351. The lead-out wall surface 355 has a substantially conical shape that gradually expands from the holding portion 351 toward the lead-out side of the lead electrode E. The introduction wall surface 353 and the lead-out wall surface 355 have a circular cross section.

As shown in FIG. 10 , the lower main guide 43 has a holding portion 431, an introduction wall 433, and an outlet wall 435, wherein the holding portion 431, the introduction wall 433, and the outlet wall 435 constitute a through hole. The holding portion 431 has a hole diameter slightly larger than the diameter of the wire electrode E. The hole diameter of the holding portion 431 is larger than the diameter of the wire electrode E, for example, in a range of about 5 μm or more and about 20 μm or less. According to the diameter of the wire electrode E, a lower wire guide 4 of an appropriate hole diameter is used. The introduction wall 433 has a generally rounded cone shape that gradually narrows from the introduction side of the wire electrode E toward the holding portion 431. The lead-out wall surface 435 has a substantially conical shape that gradually expands from the holding portion 431 toward the lead-out side of the lead electrode E. The introduction wall surface 433 and the lead-out wall surface 435 have a circular cross section.

As shown in Figures 11 and 12, the lower auxiliary guide 45 has: a retaining portion 451, an introduction wall 453 and an outlet wall 455, wherein the retaining portion 451, the introduction wall 453 and the outlet wall 455 constitute a through hole. The retaining portion 451 has a hole diameter larger than the hole diameter of the lower main guide 43. The hole diameter of the retaining portion 451 only needs to be larger than the hole diameter of the lower main guide 43, for example, about 0.6 mm. The introduction wall 453 has a roughly inverted cone shape that gradually narrows from the introduction side of the wire electrode E toward the retaining portion 451. The outlet wall 455 has a shape that gradually expands from the retaining portion 451 toward the outlet side of the wire electrode E. The introduction wall 453 has a circular cross-section.

As shown in FIG13 , the cross-section of at least a portion of the lead-out wall 455 has a polygonal shape. The polygonal shape is preferably a regular polygon. In addition, if there are too few vertices, the lower sub-guide 45 will be large. If there are too many vertices, the internal angle becomes large, and therefore, the wire electrode E is easily offset. Therefore, the polygonal shape is particularly preferably any one of a regular hexagon, a regular heptagon, a regular octagon, a regular pentagon, and a regular decagon. According to the lower sub-guide 45 of this embodiment, the wire electrode E that is tilted by the power-on assembly 23 is guided along the two faces of the polygonal shape of the lead-out wall 455, and therefore, the wire electrode E is stably maintained.

The present invention is not limited to the structure of the above-described embodiment, and various modifications or applications can be performed without departing from the technical concept of the present invention.

For example, as shown in FIG14, the cross-section of at least a portion of the introduction wall surface 333 of the upper auxiliary guide 33 may also have a shape in which each side of the polygonal shape is bent inwardly into an arc shape, instead of the polygonal shape. In addition, as shown in FIG15, the cross-section of at least a portion of the lead-out wall surface 455 of the lower auxiliary guide 45 may also have a shape in which each side of the polygonal shape is bent inwardly into an arc shape, instead of the polygonal shape. Even so, since the wire electrode E is guided along two surfaces, the wire electrode E is stably held. In particular, if it is such a shape, the wire electrode E is guided to the corner along the arc shape, so that the stable holding of the wire electrode E can be achieved more preferably.

In addition, in each guide body of the present embodiment, the inlet wall surface is directly connected to the outlet wall surface, and the retaining portion is a circular hole with substantially no height. The retaining portion may also be a cylindrical hole, but from the perspective of preventing the wire electrode E from being broken, it is ideal that the contact area with the wire electrode E is extremely small, so the retaining portion is preferably a flat hole.

1: Upper guide unit 2: Lower guide unit 3: Upper line guide 4: Lower line guide 11, 21: Housing 13, 23: Power supply assembly 15, 25: Jet nozzle 31: Upper guide fixture 33: Upper secondary guide 35: Upper main guide 41: Lower guide fixture 43: Lower main guide 45: Lower secondary guide 311, 413: Side hole 331, 351, 431, 451: Retaining part 333, 353, 433, 453: Inlet wall 335, 355, 435, 455: Outlet wall 337, 357, 437, 457: Support member 411: First lower guide fixture 412: Second lower guide fixture E: Wire electrode W: Workpiece

Fig. 1 is a perspective view of an upper guide unit and a lower guide unit. Fig. 2 is a cross-sectional view of an upper guide unit and a lower guide unit. Fig. 3 is a side view of an upper wire guide and a lower wire guide. Fig. 4 is a cross-sectional view taken along line IV-IV of Fig. 3. Fig. 5 shows a state where a first lower guide fixture and a second lower guide fixture are separated. Fig. 6 is a top view of an upper auxiliary guide. Fig. 7 is a cross-sectional view taken along line VII-VII of Fig. 6. Fig. 8 is a cross-sectional view taken along line VIII-VIII of Fig. 7, and shows a state where a wire electrode is inserted. Fig. 9 is a side cross-sectional view of an upper main guide. Fig. 10 is a side cross-sectional view of a lower main guide. Fig. 11 is a bottom view of a lower auxiliary guide. Fig. 12 is a cross-sectional view taken along line XII-XII of Fig. 11. Fig. 13 is a cross-sectional view taken along line XIII-XIII of Fig. 12, and shows a state where a wire electrode is inserted. Fig. 14 is a top cross-sectional view of an upper auxiliary guide of a modified example. Fig. 15 is a bottom cross-sectional view of a lower auxiliary guide of a modified example.

33: Upper auxiliary guide

331:Maintenance Department

333:Introduction to the wall

E: Wire electrode

Claims (8)

An upper auxiliary guide is located on the upstream side of the travel direction of the wire electrode in a wire discharge processing machine, and guides the wire electrode together with the upper main guide. The upper auxiliary guide is characterized in that it includes: a holding portion having a larger aperture than the aperture of the upper main guide; an introduction wall surface gradually narrowing from the introduction side of the wire electrode toward the holding portion; and an exit wall surface gradually widening from the holding portion toward the exit side of the wire electrode, wherein the cross section of at least a part of the introduction wall surface has: a polygonal shape or a shape obtained by bending each side of the polygonal shape inwardly into an arc shape. The upper auxiliary guide as described in claim 1, wherein the polygonal shape is any one of a regular hexagon, a regular heptagon, a regular octagon, a regular pentagon, and a regular decagon. An upper wire guide, characterized in that it comprises: the upper auxiliary guide according to claim 1; the upper main guide; and an upper guide fixture for accommodating the upper auxiliary guide and the upper main guide. The upper wire guide as described in claim 3, wherein, the upper guide fixture includes: a side hole for supplying machining fluid between the upper auxiliary guide and the upper main guide. A lower auxiliary guide is located on the downstream side of the travel direction of the wire electrode in a wire discharge processing machine, and guides the wire electrode together with the lower main guide. The lower auxiliary guide is characterized in that it includes: a holding portion having a larger aperture than the aperture of the lower main guide; an introduction wall surface gradually narrowing from the introduction side of the wire electrode toward the holding portion; and an outlet wall surface gradually widening from the holding portion toward the outlet side of the wire electrode, wherein the cross section of at least a part of the outlet wall surface has: a polygonal shape or a shape obtained by bending each side of the polygonal shape inwardly into an arc shape. The lower auxiliary guide as described in claim 5, wherein the polygonal shape is any one of a regular hexagon, a regular heptagon, a regular octagon, a regular pentagon, and a regular decagon. A lower wire guide, characterized in that it comprises: the lower auxiliary guide according to claim 5; the lower main guide; and a lower guide fixture for accommodating the lower main guide and the lower auxiliary guide. The lower wire guide as described in claim 7, wherein, the lower guide fixture includes: a side hole for supplying a machining fluid between the lower main guide and the lower auxiliary guide.

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