JPH06226542A - Compound electrode wire for wire cut electric discharge machining - Google Patents

Abstract

PURPOSE:To heighten high temperature strength and improve electric discharge characteristic and machining precision by forming an electrode wire for wire cut electric discharge machining with a core material made of a copper alloy of respectively different composition and a covering layer covering the surface of the copper alloy. CONSTITUTION:A substance composed of a copper alloy core material and a copper alloy covering layer of a separate composition covering the surface of the copper alloy core material is used as an electrode wire for wire cut electric discharge machining and the cross-section area of the core material is set to be one time or more but not more than ten times of the cross-section area. The core material copper alloy used contains at least one or more kinds of elements selected from a group composed of Zn of 10 to 20 weight percentage and Al, Mg, Sn, Ag, P, Zr, Ti, Be, Fe, rare earth elements and the like of 5 weight percentage or less and the remainder containing copper alloy while the covering layer copper alloy used contains at least one or more kinds of elements selected from a group of Zn of 30 to 45 weight percentage and the same elements mentioned above of 5 weight percentage or less and the remainder containing copper alloy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode wire used in wire cut electric discharge machining.

[0002]

2. Description of the Related Art Wire-cut electric discharge machining is performed by bringing a fine wire electrode wire into contact with a workpiece such as an iron plate placed in a dielectric fluid and rapidly energizing the wire electrode wire in contact with an object. , Is an electro-machining method that cuts a workpiece by repeatedly discharging at high speed between the electrode wire and the workpiece. Since it can form various shapes with high accuracy, it can be used for various mold manufacturing and parts processing. Widely applied in various fields.

Up to now, an electrode wire having a diameter of about 0.1 to 0.3 mm made of brass (Cu alloy containing 35% by weight of Zn) or an alloy component similar to brass has been used for wire-cut electric discharge machining.

In recent years, in the field of forming and processing, the shape of mold parts has become more complicated and the dimensions have become more precise. Therefore, even in wire-cut electric discharge machining, it is necessary to further improve the finished dimension accuracy of the workpiece, and to improve the electric discharge. There has been an increasing demand for higher processing speeds.

[0005]

In order to further increase the electric discharge machining speed in wire cut electric discharge machining, it is conceivable to increase the discharge efficiency per discharge and increase the number of discharges.

To this end, it is required that the electrode wire has more excellent discharge characteristics and also has sufficient high temperature strength to withstand the high temperature accompanying the increase in the number of discharges.

In order to further improve the discharge characteristics of the electrode wire, it is conceivable to increase the Zn content in the Cu alloy forming the electrode wire, but in order to keep the high temperature strength higher, the electrode It is preferable to keep the content of Zn in the Cu alloy forming the wire smaller.

As described above, in the conventional electrode wire, it is necessary to further improve the discharge characteristics and the high temperature strength, which are contradictory requirements, which is the reason why the electric discharge machining speed cannot be significantly increased. Was there.

The present invention has been made in order to solve the above problems, and has a straightness not inferior to the conventional electrode wire,
A new wire-cut electric discharge machining electrode wire that can realize a faster electric discharge machining speed in wire-cut electric discharge machining by maintaining the characteristics that can be made extremely thin and having excellent high-temperature strength with excellent electric discharge characteristics The purpose is to do.

[0010]

A composite electrode wire for wire-cut electric discharge machining according to the present invention comprises 10 to 20% by weight of Zn and 5% by weight or less of Al, Mg, Sn, Ag, P and Z.
A core material of a copper alloy containing at least one element selected from the group consisting of r, Ti, Be, Fe, and rare earth elements, the remainder being copper and an unavoidable impurity, and provided so as to cover the surface of the core material. , 30-45 wt% Zn and 5 wt%
The following Al, Mg, Sn, Ag, P, Zr, Ti, B
e, Fe, a coating layer of copper alloy containing at least one element selected from the group consisting of rare earth elements, the balance being copper and a copper alloy coating layer consisting of inevitable impurities, and the cross-sectional area of the core material is the cross-sectional area of the coating layer. It is characterized by being 1 time or more and 10 times or less. In the present invention, “rare earth element” means Periodic Table 3A.
Se, Y, La, Ce, Pr, Nd, Pm belonging to the group
Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b and 17 elements of Lu.

In the present invention, the "cross-sectional area" means the cross-sectional area obtained by cutting the electrode wire perpendicularly to the longitudinal direction of the wire.

The composite electrode wire for wire-cut electric discharge machining according to the present invention can be manufactured, for example, as follows.

10 to 20% by weight of Zn and 5% by weight or less of Al, Mg, Sn, Ag, P, Zr, Ti, Be,
At least 1 selected from the group consisting of Fe and rare earth elements
A melt containing at least one kind of element and the balance consisting of copper and inevitable impurities is prepared, and a cast material is manufactured by casting from this melt. A casting material is placed in the center of the mold tube according to the cast-girth method, and 30 to 45% by weight of Zn and 5% by weight are provided around the casting material.
The following Al, Mg, Sn, Ag, P, Zr, Ti, B
A composite copper alloy billet is produced by preparing and pouring a molten metal containing at least one element selected from the group consisting of e, Fe and rare earth elements, with the balance being copper and unavoidable impurities. Alternatively, according to the fitting method, 10-2
0 wt% Zn and 5 wt% or less Al, Mg, S
A cast material obtained from a molten metal containing at least one element selected from the group consisting of n, Ag, P, Zr, Ti, Be, Fe, and rare earth elements, the balance being copper and unavoidable impurities, ~ 45 wt% Zn and 5 wt% or less Al, Mg, Sn, Ag, P, Zr, Ti, Be, F
e, composite copper containing at least one element selected from the group consisting of rare earth elements, the balance being obtained from a molten metal consisting of copper and unavoidable impurities, and fitting into a cast material with the center cut An alloy billet is produced.
The cross-sectional area and the coating of the casting material to be the core material so that the cross-sectional area of the core material of the composite electrode wire, which is finally obtained in advance during the production of the composite copper alloy billet, is 1 to 10 times the cross-sectional area of the coating layer. It is desirable to adjust the ratio to the cross-sectional area of the cast material that forms the layer.

The composite copper alloy billet thus obtained is extruded by a hot extrusion method while heating at 700 to 790 ° C. to produce a composite bus bar. Furthermore, by rolling or drawing this composite bus bar by cold extrusion, the wire diameter of 0.
A composite electrode wire is manufactured by extremely thinning it to 1 to 0.3 mm.

[0015]

The present inventors have conducted extensive studies to realize a composite electrode wire which simultaneously has the excellent characteristics of alloys having different compositions by combining alloys having different compositions to form a composite electrode wire. The invention has been completed.

More specifically, the present inventors construct the core material from an alloy composition that can further increase the high temperature strength against heat generated during electric discharge machining, and further improve the discharge characteristics. By composing a coating layer from an alloy composition that enables the core material to have a cross-sectional area of 1 to 10 times the cross-sectional area of the coating layer,
As shown in the following examples, the contradictory required characteristics that could never be realized by the conventional electrode wire consisting of only brass or a Cu alloy having a composition similar to brass, that is, having higher high temperature strength and being superior This led to the realization of a composite electrode wire having excellent discharge characteristics.

In the present invention, 10 to 20% by weight of Zn
And 5% by weight or less of Al, Mg, Sn, Ag, P, Z
The core material is made of a copper alloy containing at least one element selected from the group consisting of r, Ti, Be, Fe and rare earth elements, and the balance being copper and an unavoidable impurity. This is because it has been found that the alloy composition is the most suitable for achieving an electrode wire having higher strength and excellent straightness, and also 30 to 45 wt% Zn and 5
Weight% or less of Al, Mg, Sn, Ag, P, Zr, T
i), Be, Fe, and at least one element selected from the group consisting of rare earth elements, with the balance being a copper alloy composed of copper and unavoidable impurities. This is because it was found that the alloy composition is the most suitable in order to further improve the discharge characteristics and realize an electrode wire excellent in wire drawing workability.

In the alloy composition constituting the core material of the composite electrode wire for wire-cut electric discharge machining according to the present invention, the Zn content is set to 10 to 20% by weight because the Zn content is 10% by weight. If it is less than the above, the straightness of the electrode wire is significantly lowered, and the content of Zn is 20.
This is because the high temperature strength of the electrode wire will be reduced if the weight percentage is exceeded. In addition, Al, Mg, Sn, Ag, P, Z
The content of at least one element selected from the group consisting of r, Ti, Be, Fe and rare earth elements is set to 5% by weight or less because the high temperature strength and straightness are enhanced if the content is 5% by weight or less. The effect can be expected, but if it exceeds 5% by weight, wire drawing workability may be significantly deteriorated.

In the alloy composition constituting the coating layer of the composite electrode wire for wire-cut electric discharge machining according to the present invention, the content of Zn is set to 30 to 45% by weight because the content of Zn is 30% by weight. If it is less than the above range, the discharge characteristics of the electrode wire will be deteriorated, and if the Zn content exceeds 45% by weight, the wire drawing workability of the electrode wire will be extremely deteriorated. In addition, Al, Mg, Sn, Ag, P,
The content of at least one element selected from the group consisting of Zr, Ti, Be, Fe, and rare earth elements is set to 5% by weight or less because the discharge characteristics are expected to be improved if 5% by weight or less. However, if it exceeds 5% by weight, wire drawability may be significantly deteriorated.

In the present invention, the cross-sectional area of the core material of the electrode wire is set to be 1 to 10 times the cross-sectional area of the coating layer of the electrode wire because the cross-sectional area of the core material is the cross-sectional area of the coating layer. If it is less than 1 time, the high temperature strength becomes too small and the electrical discharge machining speed during electrical discharge machining cannot be increased.
If the cross-sectional area of the core material exceeds 10 times the cross-sectional area of the coating layer, the coating layer may peel off from the surface of the core material in the manufacturing process of the composite electrode wire, especially in hot extrusion or subsequent cold extrusion. Because there is.

As described above, in the composite electrode wire for wire cut electric discharge machining according to the present invention, the high temperature strength is further enhanced in the core material, and the discharge characteristics superior in the coating layer are provided. In the above, the increase in the number of discharges and the improvement in discharge efficiency required for increasing the electric discharge machining speed are achieved.

In addition, if the electrode wire is thinned appropriately, it is possible to obtain a composite electrode wire for wire-cut electric discharge machining which can perform electric discharge machining in a shorter time and with high finished dimension accuracy.

[0023]

EXAMPLES In Table 1, composite electrode wires made of the composition alloy according to the present invention are shown in Invention Examples 1 to 12, and composite electrode wires made of other composition alloys are shown in Comparative Examples 1 to 6.

In the composite electrode wire, the composition alloys of the core material and the coating material, which are shown in weight% in Table 1, are melted and cast, and the core material casting material is fitted into the coating material casting material according to the fitting method. Then, a copper alloy composite billet having a diameter of about 17 cm was produced. This copper alloy composite billet was extruded by a hot extrusion method while being heated to 700 to 790 ° C. to prepare a composite bus bar having a diameter of 25 mm, and further, the composite bus bar was thinned to a diameter of 0.2 mm by cold extrusion to make a prototype. .

For comparison, the electrode wires made of brass or a composition alloy similar to brass are shown in Table 1 in Conventional Examples 1 to 1.
As shown in FIG.

The electrode wire of the conventional example was obtained by melting and casting the composition alloy shown in Table 1 in wt% and casting the obtained ingot at 700 to 7
The wire is extruded by a hot extrusion method while being heated to 90 ° C., and the wire obtained is subjected to cold wire drawing to obtain a diameter of 0.2 m.
It was manufactured by thinning to m.

For all the electrode wires shown in Table 1, the high temperature strength ratio, the electric discharge machining speed ratio, the straightness and the wire drawing workability were evaluated, and the results are also shown in Table 1.

However, the electric discharge machining speed ratio in this embodiment was measured by measuring the speed when an iron plate having a thickness of 50 mm was cut by wire cut electric discharge machining using each electrode wire (35% by weight of the electrode wire of Conventional Example 1). The value when the Zn-containing Cu alloy composition) was used as the standard 100 was evaluated.

The high temperature strength ratio is also a value evaluated with the electrode wire of Conventional Example 1 as a reference 100.

[0030]

[Table 1]

As is clear from the results shown in Table 1, the electrode wires according to Examples 1 to 12 of the present invention have the conventional examples 1 to 3 and the comparative example 1.
It can be seen that both the high temperature strength and the electric discharge characteristics are improved and the electric discharge machining speed ratio is significantly increased, as compared with the electrode wires of Nos. 6 to 6.

The electrode wires according to Examples 1 to 12 of the present invention are
Although the wire drawing workability was slightly inferior to that of the electrode wires of Conventional Examples 1 and 2, it was confirmed that the wire drawing workability required at the minimum for wire drawing is sufficient.

As described above, the electrode wires according to Examples 1 to 12 of the present invention have excellent straightness and excellent discharge characteristics and higher high-temperature strength. By being significantly accelerated, it is possible to provide a fully usable composite electrode wire that replaces the conventional electrode wire made of brass.

[0034]

As described above, in the composite electrode wire for wire-cut electric discharge machining according to the present invention, alloys having different compositions are compounded, the high temperature strength as a whole is further enhanced and the discharge characteristics are improved, It is possible to increase the electric discharge machining speed in wire cut electric discharge machining. If the composite electrode wire for wire cut electric discharge machining according to the present invention is made extremely thin, not only the electric discharge machining speed can be increased, but also the machining accuracy of the workpiece can be further improved.

Therefore, by using the composite electrode wire for wire-cut electric discharge machining according to the present invention, complicated dies, parts, etc. can be machined with higher machining accuracy and in a shorter time.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kenji Miyazaki 1-3-3 Shimaya, Konohana-ku, Osaka City Sumitomo Electric Industries, Ltd. Osaka Works (72) Inventor Tadaharu Ikuki 1-chome, Shimaya, Konohana-ku, Osaka No. 3 Sumitomo Electric Industries, Ltd. Osaka Works

Claims (1)

[Claims] 1. 10-20% by weight Zn and 5% by weight
The following Al, Mg, Sn, Ag, P, Zr, Ti, B
e, Fe, a core material of a copper alloy containing at least one kind of element selected from the group consisting of rare earth elements, the balance being copper and unavoidable impurities, and provided so as to cover the surface of the core material. 45% by weight
Zn and 5% by weight or less of Al, Mg, Sn, Ag,
P, Zr, Ti, Be, Fe, a coating layer of copper alloy containing at least one element selected from the group consisting of rare earth elements, with the balance being copper and a copper alloy coating consisting of unavoidable impurities. A composite electrode wire for wire-cut electric discharge machining, characterized in that the area is 1 to 10 times the cross-sectional area of the coating layer.