# US 10,307,848 B2 · Electrical discharge machining electrode wire and manufacturing method for same

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- Number: US 10,307,848 B2
- Document ID: US10307848B2
- Status: Granted
- Kind: B2
- Application number: 15/107,119
- Filed: 2014-11-07
- Published: 2017-09-14
- Granted: 2019-06-04
- Earliest claimed: 2014-11-07
- Assignees: Hitachi Metals, Ltd.
- Applicants: Hitachi Metals, Ltd.
- Inventors: Takayuki Tsuji; Hiromitsu Kuroda; Tetsuya Tokumitsu; Takamitsu Kimura; Yosuke Shiba; Hiroshi Matsuzaki; Yuichi Komuro; Shingo Amamiya
- Web page: https://patentgrep.com/patent/US10307848B2

## CPC

- B23H 7/08: Wire electrodes
- C22F 1/08: of copper or alloys based thereon
- C25D 3/22: of zinc
- C25D 5/50: by heat-treatment
- C25D 7/0607: {Wires}
- B23H: WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL (processes for the electrolytic or electrophoretic production of coatings, electroforming, or apparatus therefor C25D; processes for the electrolytic removal of material from objects C25F; manufacturing printed circuits using precipitation techniques to apply the conductive material to form the desired conductive pattern H05K3/18)
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR

## Abstract

An electrical discharge machining electrode wire includes a core including a copper or a copper alloy, and a covering layer covering a periphery of the core and including a zinc. The covering layer includes an inner layer including a γ-phase of copper-zinc based alloy and covering the periphery of the core, and an outer layer including an ε-phase of copper-zinc based alloy and covering a periphery of the inner layer. An x-ray diffraction intensity of (0001) of the ε-phase is more than twice an x-ray diffraction intensity of (332) of the γ-phase.

## Claims

### Claim 1

An electrical discharge machining electrode wire, comprising:
a core comprising copper or a copper alloy; and
a covering layer covering a periphery of the core and including zinc,
wherein the covering layer comprises an inner layer including a γ-phase of copper-zinc based alloy and covering the periphery of the core, and an outer layer including an ε-phase of copper-zinc based alloy and covering a periphery of the inner layer,
wherein an x-ray diffraction intensity of (0001) of the ε-phase is more than twice an x-ray diffraction intensity of (332) of the γ-phase, and
wherein an amount of warpage from an axis along a vertical direction is not less than 40 mm/m and not more than 80 mm/m when the electrical discharge machining electrode wire is suspended vertically after annealing with wound onto a bobbin.

### Claim 2 (depends on 1)

The electrical discharge machining electrode wire according to claim 1, wherein the outer layer is an outermost layer.

### Claim 3 (depends on 2)

The electrical discharge machining electrode wire according to claim 2, wherein the core comprises a brass.

### Claim 4 (depends on 1)

The electrical discharge machining electrode wire according to claim 1, wherein the core comprises a brass.

### Claim 5 (depends on 1)

The electrical discharge machining electrode wire according to claim 1, wherein the outer layer is an outermost layer.

### Claim 6 (depends on 1)

The electrical discharge machining electrode wire according to claim 1, wherein the core comprises a brass.

### Claim 7 (depends on 1)

The electrical discharge machining electrode wire according to claim 1, wherein the electrical discharge machining electrode wire is produced by:
plating the core with the zinc;
drawing the plated core; and
after the drawing and then winding the plated core onto the bobbin, heat treating in a heat treatment condition in a range from 100° C. to 120° C. for 3 hours to 24 hours.

### Claim 8 (depends on 7)

The electrical discharge machining electrode wire according to claim 7, wherein the heat treatment condition is in the range from 100° C. to 120° C. for 3 hours to 18 hours.

### Claim 9 (depends on 7)

The electrical discharge machining electrode wire according to claim 7, Wherein the heat treating under the heat treatment condition is conducted for 3 hours to 7 hours when the covering layer has a thickness of less than 1.5 μm.

### Claim 10 (depends on 9)

The electrical discharge machining electrode wire according to claim 9, the heat treating under the heat treatment condition is conducted for 7 hours to 18 hours when the covering layer has the thickness of not less than 1.5 μm.

### Claim 11 (depends on 1)

The electrical discharge machining electrode wire according to claim 1, wherein the amount of warpage is in a range from 40 mm/m to 70 mm/m.

### Claim 12 (depends on 1)

The electrical discharge machining electrode wire according to claim 1, wherein a difference between a maximum amount of the warpage and a minimum amount of the warpage is at most 30 mm/m.

### Claim 13 (depends on 1)

The electrical discharge machining electrode wire according to claim 1, wherein the amount of warpage is not less than 40 mm/m and not more than 80 mm/m over an entire length of the electrical discharge machining electrode wire.

### Claim 14

A method for manufacturing an electrical discharge machining electrode wire comprising a core comprising copper or a copper alloy and a covering layer covering a periphery of the core and including zinc, the method comprising:
plating the core with a zinc or a zinc alloy once;
drawing the plated core; and
after the thawing and then winding the plated core onto a bobbin, heat treating in a heat treatment condition under which the covering layer comprises an inner layer including a γ-phase of copper-zinc based alloy and an outer layer including an ε-phase of copper-zinc based alloy and coveting a periphery of the inner layer, an x-ray diffraction intensity of (0001) of the ε-phase is more than twice an x-ray diffraction intensity of (332) of the γ-phase, and the heat treatment condition is in a range from 100° C. to 120° C. for 3 hours to 24 hours,
wherein an amount of warpage from an axis along a vertical direction is not less than 40 mm/m and not more than 80 mm/m when the electrical discharge machining electrode wire is suspended vertically after annealing with wound onto the bobbin.

### Claim 15 (depends on 14)

The method according to claim 14, wherein the heat treatment condition is in the mime from 100° C. to 120° C. for 3 hours to 18 hours.

### Claim 16 (depends on 14)

The method according to claim 14, wherein the heat treating milder the heat treatment condition is conducted for 3 hours to 7 hours when the covering layer has a thickness of less than 1.5 μm.

### Claim 17 (depends on 16)

The method according to claim 16, wherein the heat treating under the heat treatment condition is conducted for 7 hours to 18 hours when the covering layer has the thickness of not less than 1.5 μm.

### Claim 18 (depends on 14)

The method according to claim 14, wherein the amount of warpage is in a range from 40 mm/m to 70 mm/m.

### Claim 19 (depends on 14)

The method according to claim 14, wherein a difference between a maximum amount of the warpage and a minimum amount of the warpage is at most 30 mm/m.